Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductan...Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.展开更多
The photosynthetic functions and the sensitivity to photoinhibition were compared between two superhigh_yield hybrid rice (Oryza sativa L.) Liangyoupeijiu and X07S/Zihui 100, the newly developed from two parental line...The photosynthetic functions and the sensitivity to photoinhibition were compared between two superhigh_yield hybrid rice (Oryza sativa L.) Liangyoupeijiu and X07S/Zihui 100, the newly developed from two parental lines and traditional hybrid rice Shanyou 63 developed from three parental lines. The results showed that, as compared to Shanyou 63, the net photosynthetic rate of Liangyoupeijiu and X07S/Zihui 100 was 9.1% and 11.9% higher, the transpiration rate was 37.4% and 31.4% lower, and their water use efficiency was 74.2% and 63.5% higher respectively. After strong light (2 000 μmol photons·m -2 ·s -1 ) treatment for 2 h, the photochemical quantum yield and the photochemical quenching increased by 37.0% and 18.0% respectively in Liangyoupeijiu, 28.3% and 46.2% in X07S/Zihui 100, but decreased a little in Shanyou 63. The non_photochemical quenching decreased in Liangyoupeijiu and X07S/Zihui 100 (about 50%) but increased greatly in Shanyou 63 (about 50%). Better photosynthetic functions, higher water use efficiency and stronger resistance to photoinhibition, may be the physiological basis for the super high_yield of the two hybrid rice under study.展开更多
Four winter wheat (Triticum aestivum L.) varieties ('JD 8', 'Jing 411','Centurk' and 'Tam 202') were used to study the effect of heat stress on photosynthetic characteristics of flag le...Four winter wheat (Triticum aestivum L.) varieties ('JD 8', 'Jing 411','Centurk' and 'Tam 202') were used to study the effect of heat stress on photosynthetic characteristics of flag leaf blade, nag leaf sheath, peduncle, glume, lemma and awn during grain-filling stage. The results showed that heat acclimation during grain-filling stage increased thermotolerance of wheat with significant differences among different green organs. During heat stress, the decreases of the efficiency of primary light energy conversion (F-v/F-m) of PS II and pigment (chlorophyll and carotenoid) content were much slower in peduncle, flag leaf sheath and glume than in nag leaf blade, lemma and ann; and the percentage of decrease in net photosynthetic rate (P-n) of ear was lower than that of the nag leaf blade. The measured photosynthetic parameters (F-v/F-m, P-n and pigment content) of 'JD 8', a relatively heat tolerant variety, declined more slowly than those of the other three varieties during the whole heat stress period.展开更多
[Objective] The aim of this study was to explore the daily change of photosyntheticratefor Prunus domestica ×armeniacain different growing seasons. The study can provide theoretical basis for arid area high yield...[Objective] The aim of this study was to explore the daily change of photosyntheticratefor Prunus domestica ×armeniacain different growing seasons. The study can provide theoretical basis for arid area high yield and quality cultivation.[Method] The photosynthetic physiological properties of leaves of different types of Prunus domestica × armeniaca were measured by the Li-6400 portable photosynthesis system indifferent seasons. By this method could analysis of photosyntheticcharacteristicsfor different types of Prunus domestica×armeniaca in different seasons.[Result] Daily change of photosyntheticrate（Pn） for Prunus domestica×armeniaca in differentseasons showed a ＂double-peak＂ curve. The peak values were at 10：00 and16：00. The Pn of ‘Fengweihuanghou＇, ‘Konglongdan＇, ‘Weihou＇, ‘Weiwang＇ and‘Weidi＇ reached the maximum in July, theywere 13.75, 14.76, 12.96, 13.3, and 11.9μmol/（m^2·s）, respectively. The Pn of Prunus domestica×armeniaca reached minimumin August, they were 9.78, 10.71, 12.02, 10.43 μmol/（m^2·s）. The Pn overall average of ‘Konglongdan＇ was highest,it reached 12.65 μmol/（m^2·s）.The Pn overall average of ‘Weiwang＇ was lowest, it reached 11.31μmol/（m^2·s）. There were extremely significant positive correlation between the Pn and Gs（P0.01）. [Conclusion] Daily change of photosyntheticrate for Prunus domestica ×armeniaca in differentseasons showed a ＂double-peak＂ curve, showing significant phenomenon of ＂midday depression＂.The photosynthesis intensity of Prunus domestica ×armeniaca was strongest in July, and the photosynthesis intensity was weakest in August. ‘Konglongdan＇showed the strongest photosynthesis capacity, ‘Weihou＇ and ‘Weiwang＇, followed.There were highest correlation between the Pn and stoma conductance（Gs）.展开更多
One-year-old seedlings of Amur maple (Acer ginnala Maxim), Ussurian pear (Pyrus ussuriensis Maxim) and David peach (Prunus davidiana Carr) were planted in pots in greenhouse and treated with four different soil moistu...One-year-old seedlings of Amur maple (Acer ginnala Maxim), Ussurian pear (Pyrus ussuriensis Maxim) and David peach (Prunus davidiana Carr) were planted in pots in greenhouse and treated with four different soil moisture contents (75.0%, 61.1%, 46.4% and 35.4%). The results showed that net photosynthesis rate (NPR), transpiration rate (TR) and stomatal conductance (Sc) of seedlings of the three species decreased with the decease of soil moisture content, and Amur maple seedlings had the greatest change in those physiological indices, followed by Ussurian pear, David peach. Amur maple and Ussurian pear seedlings also presented a decrease tendency in water use efficiency (WUE) under lower soil moisture content, whereas this was reversed for David peach. Under water stress the biomass allocation to seedling root had a significant increase for all the experimental species. As to root/shoot ratio, Amur maple seedlings had the biggest increase, while David peach had the smallest increase. The leaf plasticity of Amur maple seedlings was greater, the leaf size and total leaf area decreased significantly as the stress was intensified. No significant change of leaf size and total leaf area was found in seedlings of Ussurian pear and David peach. It was concluded that Amur maple was more tolerant to soil moisture stress in comparison with David peach and Ussurian pear.展开更多
To evaluate the effects of solar greenhouse with different structure and CO2 enrichment on illumination and temperature performance of greenhouse and cucumber growth and development in the central region of Inner Mong...To evaluate the effects of solar greenhouse with different structure and CO2 enrichment on illumination and temperature performance of greenhouse and cucumber growth and development in the central region of Inner Mongolia, the research used traditional solar greenhouse （A） and blanket-inside solar greenhouse（B）, and set 4 treatments： AE （traditional solar greenhouse A with CO2 enrichment）, AN （traditional solar greenhouse A without CO2 enrichment）, BE （blanket-inside solar greenhouse B with CO2 enrichment） and BN （blanket-inside solar greenhouse B without CO2 enrichment）, to explore the influence of cucumber growth, photosynthetic property, quality and yield in different structure solar greenhouses with CO2 enrichment. The results showed that the illumination and temperature in blanket-inside solar greenhouse was superior to traditional solar greenhouse, and the average light intensity in blanket-inside solar greenhouse increased by 21.05%, compared with traditional solar greenhouse. Under the condition of same greenhouse structure, stem height ,average stem diameter, contents of soluble sugar, vitamin C, net photosynthetic rate and yield showed any significant difference between the treatments with CO2 enrichment or not. Under the condition of same CO2 concentration, BE cucumber average stem height, average stem diameter, contents of soluble sugar, net photosynthetic rate and yield in BE was higher than which in AE. Therefore, the optimization in structure of blanket-inside solar greenhouse remarkably improved illumination and temperature property, combining with CO2 enrichment as application technology, there was crucial significance to promote the greenhouse performance and improve the efficiency of greenhouse vegetable production.展开更多
Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former researcher results. Then, considering some environmental factors influencing on leaf ph...Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former researcher results. Then, considering some environmental factors influencing on leaf photosynthesis, three numerical sensitivity experiments were carried out. We simulated the sing le leaf net CO2 assimilation, which acts as a function of different light, carbo n dioxide and temperature conditions. The relationships between leaf net photosy nthetic rate of C3 and C4 plant with CO2 concentration intercellular, leaf tempe rature, and photosynthetic active radiation (PAR) were presented, respectively. The results show the numerical experiment may indicate the main characteristic o f plant photosynthesis in C3 and C4 plant, and further can be used to integrate with the regional climate model and act as land surface process scheme, and bett er understand the interaction between vegetation and atmosphere.展开更多
The N2O emission rates, photosynthesis, respiration and stomatal conductance of the dominant tree species from broadleaf/Korean pine forest in Changbai Mountain were measured by simulated water stress with the closed ...The N2O emission rates, photosynthesis, respiration and stomatal conductance of the dominant tree species from broadleaf/Korean pine forest in Changbai Mountain were measured by simulated water stress with the closed bag-gas chromatography. A total of five species seedlings were involved in this study, i.e.,Pinus koraiensis Sieb. et Zucc,Fraxinus mandshurica Rupr,Juglans mandshurica Maxim,Tilia amurensis Rupr, andQuercus mongolica Fisch. ex Turcz.. The results showed that the stomatal conductance, net photosynthetic rate and N2O emission of leaves were significantly reduced under the water stress. The stoma in the leaves of trees is the main pathway of N2O emission. N2O emission in the trees mainly occurred during daytime. N2O emission rates were different in various tree specie seedlings at the same water status. In the same tree species, N2O emission rates decreased as the reduction of soil water contents. At different soil water contents (MW, LW) the N2O emission rates ofPinus koraiensis decreased by 34.43% and 100.6% of those in normal water condition, respectively. In broadleaf arbor decreased by 31.93% and 86.35%, respectively. Under different water stresses N2O emission rates in five tree species such asPinus koraiensis, Fraxinus mandshurica, Juglans mandshurica, Tilia amurensis, andQuercus mongolica were 38.22, 14.44, 33.02, 16.48 and 32.33 ngN2O·g?1DW·h?1, respectively. Keywords Trees - N2O emission rate - Soil water stress - broadleaf/Korean pine forest - Changbai Mountain CLC number S718.55 Document code A Foundation item: This project was supported by the National Natural Science Foundation of China (No. 30271068), the grant of the Knowledge Innovation Program of Chinese Academy of Sciences (KZ-CX-SW-01-01B-10), and the Special Funds for Major State Basic Research Program of China (No. G1999043407)Biography: Wang Miao (1964-), male, associate professor in Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, P. R. China.Responsible editor: Song Funan展开更多
To compare the transformation effects of two different forms （cDNA in monocotyledonous plant Echinochloa crusgalli, DNA in monocotyledonous plant Zea mays） of phosphoenolpyruvate carboxylase （PEPC） gene （Ppc） on...To compare the transformation effects of two different forms （cDNA in monocotyledonous plant Echinochloa crusgalli, DNA in monocotyledonous plant Zea mays） of phosphoenolpyruvate carboxylase （PEPC） gene （Ppc） on the growth of transgenic dicotyledonous plant, Agrobacterium-mediated transformation of Ppc genes into Nicotiana tabacum were carried out. Transgenic leaf plates and differentiated seedling leaves were verified by GUS histochemistry, PCR, and RT-PCR. Results showed that transgenic N. tabacum with Ppc-cDNA of E. crusgalli had relatively strong differentiation ability. However, N. tabacum after transformation of complete DNA sequence of Ppc genes in Z mays had relatively poor ability of growth. The differentiated green seedlings had the phenomenon of yellowing; and photosynthesis ability of leaves was poor. This might be caused by the misidentification and wrong splicing in transcription. This indicated that the expression rate of monocotyledonous complete DNA might be reduced in the monocotyledonous cells with relatively far genetic distances. Detection results of showed that Pn in most transgenic N. tabacum with Ppc-cDNA of E. crusgalli was was higher than that in control, which preliminarily proved that PEPC of monocotyledonous plant E. crusgalli had certain regulatory effects on photosynthesis of N. tabacum.展开更多
Three winter wheat cultivars ( Triticum aestivum L.), representatives of those widely cultivated in Beijing over the past six decades, were grown in the same environmental condition, and their physiological features w...Three winter wheat cultivars ( Triticum aestivum L.), representatives of those widely cultivated in Beijing over the past six decades, were grown in the same environmental condition, and their physiological features were investigated. Daily changes of net photosynthetic rate (P-n), transpiration (T-r) in different growth stages were measured in order to find the relationship between leaf photosynthesis and yield. Instantaneous water use efficiency (WUE) of leaf was calculated from P-n/T-r. It is suggested that relationship between photosynthetic rate and yield changed with the developing stages of wheat. High yield wheat cultivar Jingdong 8 (released in the 1990s) had a higher photosynthetic rate ( the maximal P-n increased by 77%) and transpiration rate (the maximal T-r increased by 69%), but a lower WUE than the low yield cultivar Yanda 1817 (released in the 1940s) during the day time at stem elongation stage. However; difference of P-n among the three cultivars changed with wheat growth process. Before 10 o'clock P-n in leaves of Jingdong 8 usually was the highest of the three cultivars, but P-n of Yanda 1817 was the highest after 10 o'clock. At dough ripe stage, P-n in leaves of Yanda. 1817 was the highest among the three cultivars during the whole day. The difference of changing trend of transpiration in three wheat cultivars was similar to P,, but WUE of Yanda 1817 was the highest in those three cultivars, indicating that the higher yield of Jingdong 8 was achieved via a greater consumption of water. Contrary to the cultivars released in the later period, midday depression of photosynthesis was small in Yanda 1817, which might suggest that Yanda 1817 was resistant to photoinhibition. It is possible that photosynthetic potential in leaves of wheat increased as wheat cultivars was improved over the past six decades. However, it became less resistant to photoinhibition.展开更多
Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former researcher results. Then, considering some environmental factors influencing on leaf ph...Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former researcher results. Then, considering some environmental factors influencing on leaf photosynthesis, three numerical sensitivity experiments were carried out. We simulated the sing le leaf net CO2 assimilation, which acts as a function of different light, carbo n dioxide and temperature conditions. The relationships between leaf net photosy nthetic rate of C3 and C4 plant with CO2 concentration intercellular, leaf tempe rature, and photosynthetic active radiation (PAR) were presented, respectively. The results show the numerical experiment may indicate the main characteristic o f plant photosynthesis in C3 and C4 plant, and further can be used to integrate with the regional climate model and act as land surface process scheme, and bett er understand the interaction between vegetation and atmosphere.展开更多
Effects of NaCI on seed germination, leaf gas exchange and seedling growth were investigated. The germination of P. tatarinowii seeds was delayed in the presence of NaCl, and was significantly inhibited when NaCl conc...Effects of NaCI on seed germination, leaf gas exchange and seedling growth were investigated. The germination of P. tatarinowii seeds was delayed in the presence of NaCl, and was significantly inhibited when NaCl concentration exceeded 17 mM （1.0 g·L^-1）. NaCl treatments induced reductions of transpiration rate, stomatal conductance and net photosynthetic rate and their reductions were significant with the increasing of NaCl concentration. However, intercellular CO2 concentration in seedling leaves under salt stress was significantly higher than that of controls. There was a significant reduction in survival, basal diameter increment and height increment witl increasing NaCl concentration 50 days after NaCl treatment, and a significant reduction in the dry weight increment of roots, stems, and leaves was also observed in the NaCl treatments. The deleterious effect on the biomass increment was more evident in the case of stems and leaves. Results from this study suggest that P. tatarinowii is sensitive to salinity stress and the salinity threshold for seedling growth might be less 34 mM （2.0 g· L^-1）.展开更多
The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods. Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon （COe and HCO3-） by plant...The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods. Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon （COe and HCO3-） by plants. The net photosynthetic COa assimilation （PN）, the photosynthetic assimilation of CO2 and bicarbonate （PN＇）, the proportion of increased leaf area （lEA） and the stable carbon isotope composition （δ13C） of Orychophragmus violaceus （Ov） and Brassica juncea （B j） under three bicarbonate levels （5, 10 and 15 mm NaHCO3） were examined to determine the relationship among PN, PN＇ and fLA. PN＇, not PN, changed synchronously with fLA. Moreover, the proportions of exogenous bicarbonate and total bicarbonate （including exogenous bicarbonate and dissolved CO2-generated bicarbonate） utilised by Ov were 2.27 % and 5.28 % at 5 mm bicarbonate, 7.06 % and 13.28 % at 10 mm bicarbonate, and 8.55 % and 17.31% at 15 mm bicarbonate, respectively. Meanwhile, the propor- tions of exogenous bicarbonate and total bicarbonate uti- lised by Bj were 1.77 % and 3.28 % at 5 mm bicarbonate, 2.11% and 3.10 % at 10 mm bicarbonate, and 2.36 % and 3.09 % at 15 mm bicarbonate, respectively. Therefore, the dissolved CO2-generated bicarbonate and exogenous bicarbonate are important sources of inorganic carbon for plants.展开更多
The strong adaptability of Broussonetia papyrifera （L.） Vent. to low phosphorus （P） conditions can be attributed to the large amount of root-exuded organic acids and the high efficiency of P extraction. However, m...The strong adaptability of Broussonetia papyrifera （L.） Vent. to low phosphorus （P） conditions can be attributed to the large amount of root-exuded organic acids and the high efficiency of P extraction. However, microelement contents are influenced by low-P stress, and their effects on the photosynthetic capability of B. pa- pyrifera remain unknown. In this study, we investigated the effects of low-P treatment on net photosynthetic rate （PN）; chlorophyll a fluorescence （ChlF） characteristics; and Fe, Mn, Cu, and Zn contents of B. papyrifera and Morus alba L. seedlings. Results show that B. papyrifera exhibited better photosynthetic capability under moderate P defi- ciency （0.125, 0.063, and 0.031 mmol/L P treatments）, whereas the photosynthetic capability of M. alba decreased under moderate and severe P deficiency （0.016 and 0 mmol/L P treatments）. Under moderate P deficiency, the decrease in Cu and Zn contents in B. papyrifera was lower than that in M. alba. Under severe P deficiency, a consid- erable decrease of photosynthetic capability in B. pa- pyrifera and M. alba was associated with low Cu and Zn contents. The PN of the two Moraceae species exhibited a better correlation with Cu and Zn contents than with Fe or Mn content. P deficiency could not only decrease cyclic photophorylation and photosynthetic efficiency, but could also affect the stability of thylakoid membrane structureand electron transport efficiency by influencing the con- tents of Cu or Zn, thereby affecting photosynthesis.展开更多
The parameters of gas exchange and chlorophyl fluorescence in leaves of six rare and endangered species Neolitsea sericea, Cinnamomum japonicum var. cheni , Sinojackia microcarpa, Discocleidion glabrum var. trichocarp...The parameters of gas exchange and chlorophyl fluorescence in leaves of six rare and endangered species Neolitsea sericea, Cinnamomum japonicum var. cheni , Sinojackia microcarpa, Discocleidion glabrum var. trichocarpum, Parrotia sub-aequalis, Cercidiphyl um japonicum were measured in fields. The results showed that there were significant differences in photosynthetic capacity, intrinsic water use effi-ciency （WUEi ）, the efficiency of primary conversion of light energy of PSⅡ and its potential activity, the quantum yield of PSⅡ electron transport, and the potential ca-pacity of heat dissipation among the six species. However, there was no significant difference in WUE. The highest values of net photosynthetic rate （Pn）, transpiration rate （Tr） and stomatal conductance （gs） occurred in D. glabrum var. trichocarpum and the lowest in S. microcarpa. On the contrary, D. glabrum var. trichocarpum had the lowest WUE, intrinsic water use efficiency （WUEi ） and S. microcarpa had the highest. The results indicated that D. glabrum var. trichocarpum had higher photo-synthetic capacity and poorer WUE, while S. microcarpa had lower photosynthetic capacity and greater WUE. Furthermore, the mean values of maximal fluorescence （Fm）, potential efficiency of primary conversion of light energy of PSⅡ （Fv/Fm）,ΦPSⅡ, actual efficiency of primary conversion of light energy of PSⅡ （F′v/F′m） and non-photochemical quenching coefficient （NPQ） were the highest in S. micro-carpa, indicating that its PSⅡ had higher capacity of heat dissipation and could prevent photosynthetic apparatus from damage by excessive light energy. Correlation analysis showed that there were significant correlations among photosynthetic physi-ological parameters. However, the initial fluorescence （Fo） was not significantly cor-related with any other parameters. This study also revealed the extremely significant positive correlations between Pn and Tr, gs, apparent quantum yield （AQY）, be-tween Tr and gs, between light saturation point （LSP） and AQY, between Fv/Fm and Fm, between ΦPSⅡ and photochemical quenching coefficient （qp）, between Tr, gs and LSP, AQY. However, WUEi was significantly negatively correlated with Tr, gs, Pn, LSP and AQY.展开更多
Soil pot experiments were conducted in a greenhouse to examine the effects of different nitrogen （N） supply （low, 0.15 g N/kg; middle, 0.3 g N/kg; and high, 0.6 g N/kg dry soil） on the growth, photosynthetic chara...Soil pot experiments were conducted in a greenhouse to examine the effects of different nitrogen （N） supply （low, 0.15 g N/kg; middle, 0.3 g N/kg; and high, 0.6 g N/kg dry soil） on the growth, photosynthetic characteristics and photosynthetic nitrogen use efficiency （PNUE） of tobacco seedlings （Nicotiana tabacum L. Yunyan 87）. The results showed middle and high N significantly enhanced seedling growth including plant stem and leaf dry weight comparing with low N. High N supply could lead to a dramatic increase in the photosynthetic capacity of tobacco seedlings under low N conditions. There were significant differences in leaf N content between nitrogen treatments. About a 76% increase in leafN content in plants fed by high N resulted in about 43% increase in Rubisco content and 27% in net photosynthetic rate. The non-corresponding increases in photosynthetic rate in tobacco seedlings fed by high N relative to low N resulted from Rubisco activity and/or carboxylation efficiency （CE）. These results indicated that tobacco seedlings under high N application can maintain high net photosynthetic rate （Pn） but lower PNUE, will finally result in a decline in N use efficiency.展开更多
[Objective]The aim was to measure photosynthetic characters of SC 205, a cassava cultivar, and explore the relationships of the net photosynthetic rate （Pn） with physiological and ecological factors. [Method] The di...[Objective]The aim was to measure photosynthetic characters of SC 205, a cassava cultivar, and explore the relationships of the net photosynthetic rate （Pn） with physiological and ecological factors. [Method] The diurnal variations of photosyn-thesis in leaves of SC205 were studied by LICOR-6400 portable photosynthesis system, and the relationships of the net photosynthetic rate （Pn） with physiological and ecological factors were studied by simple correlation analysis and path analysis. [Result] The curve of diurnal variation of Pn showed single peak at 10：00 am at 24.07 μ mol CO2 m2/s, without showing midday depression; the diurnal changes of stomatal conductance （Gs）, transpiration rate （Tr）, leaf temperature （Tl）, air tempera-ture （Ta） and photosynthetic active radiation （PAR） al showed single peak curves, and there were positive relationships of Pn with Gs, Tr, Tl, Ta and PAR. The diur-nal variations of intercellular CO2 concentration （Ci）, atmospheric CO2 concentration （Ca）, relative humidity （RH） showed in a U-shape curve. There were highly signifi-cant positive correlation of Pn with Gs and PAR; the diurnal variation of Pn had highly significant negative correlations with Ci and Ca. The direct impact of physio-logical factors on Pn was as fol ows： Ci＆gt;Gs＆gt;Tl＆gt;Tr, and the direct impact of ecologi-cal factors was RH＆gt;PAR＆gt;Ca＆gt;Ta. [Conclusion] The research showed that Ci, Gs and Tr play very important roles in the changes of Pn among the physiological fac-tors, and PAR and Ca affect the changes of Pn among the ecological factors.展开更多
In this article we consider the kth-order discrete delay survival red blood cells model. The general form of the discrete dynamical system is rewritten as Xn＋l = f（Pn,δn,xn,... ,xn＋1） where Pn,δn converge to the...In this article we consider the kth-order discrete delay survival red blood cells model. The general form of the discrete dynamical system is rewritten as Xn＋l = f（Pn,δn,xn,... ,xn＋1） where Pn,δn converge to the parametric values P and 6. We show that when the parameters are replaced by sequences, the stability results of the original system still hold.展开更多
文摘Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.
基金The State Key Basic Research and Development Plan(G1998010100)The Innovative Foundation of Laboratory of Photosynthesis Basic Research,Insitute of Botany,The Chinese Academy of Sciences
文摘The photosynthetic functions and the sensitivity to photoinhibition were compared between two superhigh_yield hybrid rice (Oryza sativa L.) Liangyoupeijiu and X07S/Zihui 100, the newly developed from two parental lines and traditional hybrid rice Shanyou 63 developed from three parental lines. The results showed that, as compared to Shanyou 63, the net photosynthetic rate of Liangyoupeijiu and X07S/Zihui 100 was 9.1% and 11.9% higher, the transpiration rate was 37.4% and 31.4% lower, and their water use efficiency was 74.2% and 63.5% higher respectively. After strong light (2 000 μmol photons·m -2 ·s -1 ) treatment for 2 h, the photochemical quantum yield and the photochemical quenching increased by 37.0% and 18.0% respectively in Liangyoupeijiu, 28.3% and 46.2% in X07S/Zihui 100, but decreased a little in Shanyou 63. The non_photochemical quenching decreased in Liangyoupeijiu and X07S/Zihui 100 (about 50%) but increased greatly in Shanyou 63 (about 50%). Better photosynthetic functions, higher water use efficiency and stronger resistance to photoinhibition, may be the physiological basis for the super high_yield of the two hybrid rice under study.
文摘Four winter wheat (Triticum aestivum L.) varieties ('JD 8', 'Jing 411','Centurk' and 'Tam 202') were used to study the effect of heat stress on photosynthetic characteristics of flag leaf blade, nag leaf sheath, peduncle, glume, lemma and awn during grain-filling stage. The results showed that heat acclimation during grain-filling stage increased thermotolerance of wheat with significant differences among different green organs. During heat stress, the decreases of the efficiency of primary light energy conversion (F-v/F-m) of PS II and pigment (chlorophyll and carotenoid) content were much slower in peduncle, flag leaf sheath and glume than in nag leaf blade, lemma and ann; and the percentage of decrease in net photosynthetic rate (P-n) of ear was lower than that of the nag leaf blade. The measured photosynthetic parameters (F-v/F-m, P-n and pigment content) of 'JD 8', a relatively heat tolerant variety, declined more slowly than those of the other three varieties during the whole heat stress period.
基金Supported by High-quality and High-efficient Cultivation Technology Demonstration and Promotion of Apricot and Plum(ZYLYKJTG2015020)~~
文摘[Objective] The aim of this study was to explore the daily change of photosyntheticratefor Prunus domestica ×armeniacain different growing seasons. The study can provide theoretical basis for arid area high yield and quality cultivation.[Method] The photosynthetic physiological properties of leaves of different types of Prunus domestica × armeniaca were measured by the Li-6400 portable photosynthesis system indifferent seasons. By this method could analysis of photosyntheticcharacteristicsfor different types of Prunus domestica×armeniaca in different seasons.[Result] Daily change of photosyntheticrate（Pn） for Prunus domestica×armeniaca in differentseasons showed a ＂double-peak＂ curve. The peak values were at 10：00 and16：00. The Pn of ‘Fengweihuanghou＇, ‘Konglongdan＇, ‘Weihou＇, ‘Weiwang＇ and‘Weidi＇ reached the maximum in July, theywere 13.75, 14.76, 12.96, 13.3, and 11.9μmol/（m^2·s）, respectively. The Pn of Prunus domestica×armeniaca reached minimumin August, they were 9.78, 10.71, 12.02, 10.43 μmol/（m^2·s）. The Pn overall average of ‘Konglongdan＇ was highest,it reached 12.65 μmol/（m^2·s）.The Pn overall average of ‘Weiwang＇ was lowest, it reached 11.31μmol/（m^2·s）. There were extremely significant positive correlation between the Pn and Gs（P0.01）. [Conclusion] Daily change of photosyntheticrate for Prunus domestica ×armeniaca in differentseasons showed a ＂double-peak＂ curve, showing significant phenomenon of ＂midday depression＂.The photosynthesis intensity of Prunus domestica ×armeniaca was strongest in July, and the photosynthesis intensity was weakest in August. ‘Konglongdan＇showed the strongest photosynthesis capacity, ‘Weihou＇ and ‘Weiwang＇, followed.There were highest correlation between the Pn and stoma conductance（Gs）.
基金This study was supported by Science and Technology Program of Heilongjiang Province (GC01KB213), and the Quick Response of Basic Research Supporting Program (2001CCB00600)
文摘One-year-old seedlings of Amur maple (Acer ginnala Maxim), Ussurian pear (Pyrus ussuriensis Maxim) and David peach (Prunus davidiana Carr) were planted in pots in greenhouse and treated with four different soil moisture contents (75.0%, 61.1%, 46.4% and 35.4%). The results showed that net photosynthesis rate (NPR), transpiration rate (TR) and stomatal conductance (Sc) of seedlings of the three species decreased with the decease of soil moisture content, and Amur maple seedlings had the greatest change in those physiological indices, followed by Ussurian pear, David peach. Amur maple and Ussurian pear seedlings also presented a decrease tendency in water use efficiency (WUE) under lower soil moisture content, whereas this was reversed for David peach. Under water stress the biomass allocation to seedling root had a significant increase for all the experimental species. As to root/shoot ratio, Amur maple seedlings had the biggest increase, while David peach had the smallest increase. The leaf plasticity of Amur maple seedlings was greater, the leaf size and total leaf area decreased significantly as the stress was intensified. No significant change of leaf size and total leaf area was found in seedlings of Ussurian pear and David peach. It was concluded that Amur maple was more tolerant to soil moisture stress in comparison with David peach and Ussurian pear.
文摘To evaluate the effects of solar greenhouse with different structure and CO2 enrichment on illumination and temperature performance of greenhouse and cucumber growth and development in the central region of Inner Mongolia, the research used traditional solar greenhouse （A） and blanket-inside solar greenhouse（B）, and set 4 treatments： AE （traditional solar greenhouse A with CO2 enrichment）, AN （traditional solar greenhouse A without CO2 enrichment）, BE （blanket-inside solar greenhouse B with CO2 enrichment） and BN （blanket-inside solar greenhouse B without CO2 enrichment）, to explore the influence of cucumber growth, photosynthetic property, quality and yield in different structure solar greenhouses with CO2 enrichment. The results showed that the illumination and temperature in blanket-inside solar greenhouse was superior to traditional solar greenhouse, and the average light intensity in blanket-inside solar greenhouse increased by 21.05%, compared with traditional solar greenhouse. Under the condition of same greenhouse structure, stem height ,average stem diameter, contents of soluble sugar, vitamin C, net photosynthetic rate and yield showed any significant difference between the treatments with CO2 enrichment or not. Under the condition of same CO2 concentration, BE cucumber average stem height, average stem diameter, contents of soluble sugar, net photosynthetic rate and yield in BE was higher than which in AE. Therefore, the optimization in structure of blanket-inside solar greenhouse remarkably improved illumination and temperature property, combining with CO2 enrichment as application technology, there was crucial significance to promote the greenhouse performance and improve the efficiency of greenhouse vegetable production.
基金Natural Science Foundation of China (Grant No. 39900084)
文摘Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former researcher results. Then, considering some environmental factors influencing on leaf photosynthesis, three numerical sensitivity experiments were carried out. We simulated the sing le leaf net CO2 assimilation, which acts as a function of different light, carbo n dioxide and temperature conditions. The relationships between leaf net photosy nthetic rate of C3 and C4 plant with CO2 concentration intercellular, leaf tempe rature, and photosynthetic active radiation (PAR) were presented, respectively. The results show the numerical experiment may indicate the main characteristic o f plant photosynthesis in C3 and C4 plant, and further can be used to integrate with the regional climate model and act as land surface process scheme, and bett er understand the interaction between vegetation and atmosphere.
基金The National Natural Science Foundation of China (No. 30271068) the grant of the Knowledge Inno-vation Program of Chinese Academy of Sciences (KZ-CX-SW-01-01B-10) and the Special Funds for Major State Basic Research Pr
文摘The N2O emission rates, photosynthesis, respiration and stomatal conductance of the dominant tree species from broadleaf/Korean pine forest in Changbai Mountain were measured by simulated water stress with the closed bag-gas chromatography. A total of five species seedlings were involved in this study, i.e.,Pinus koraiensis Sieb. et Zucc,Fraxinus mandshurica Rupr,Juglans mandshurica Maxim,Tilia amurensis Rupr, andQuercus mongolica Fisch. ex Turcz.. The results showed that the stomatal conductance, net photosynthetic rate and N2O emission of leaves were significantly reduced under the water stress. The stoma in the leaves of trees is the main pathway of N2O emission. N2O emission in the trees mainly occurred during daytime. N2O emission rates were different in various tree specie seedlings at the same water status. In the same tree species, N2O emission rates decreased as the reduction of soil water contents. At different soil water contents (MW, LW) the N2O emission rates ofPinus koraiensis decreased by 34.43% and 100.6% of those in normal water condition, respectively. In broadleaf arbor decreased by 31.93% and 86.35%, respectively. Under different water stresses N2O emission rates in five tree species such asPinus koraiensis, Fraxinus mandshurica, Juglans mandshurica, Tilia amurensis, andQuercus mongolica were 38.22, 14.44, 33.02, 16.48 and 32.33 ngN2O·g?1DW·h?1, respectively. Keywords Trees - N2O emission rate - Soil water stress - broadleaf/Korean pine forest - Changbai Mountain CLC number S718.55 Document code A Foundation item: This project was supported by the National Natural Science Foundation of China (No. 30271068), the grant of the Knowledge Innovation Program of Chinese Academy of Sciences (KZ-CX-SW-01-01B-10), and the Special Funds for Major State Basic Research Program of China (No. G1999043407)Biography: Wang Miao (1964-), male, associate professor in Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, P. R. China.Responsible editor: Song Funan
基金Supported by the Innovation Project of Chinese Academy of Agricultural Sciences~~
文摘To compare the transformation effects of two different forms （cDNA in monocotyledonous plant Echinochloa crusgalli, DNA in monocotyledonous plant Zea mays） of phosphoenolpyruvate carboxylase （PEPC） gene （Ppc） on the growth of transgenic dicotyledonous plant, Agrobacterium-mediated transformation of Ppc genes into Nicotiana tabacum were carried out. Transgenic leaf plates and differentiated seedling leaves were verified by GUS histochemistry, PCR, and RT-PCR. Results showed that transgenic N. tabacum with Ppc-cDNA of E. crusgalli had relatively strong differentiation ability. However, N. tabacum after transformation of complete DNA sequence of Ppc genes in Z mays had relatively poor ability of growth. The differentiated green seedlings had the phenomenon of yellowing; and photosynthesis ability of leaves was poor. This might be caused by the misidentification and wrong splicing in transcription. This indicated that the expression rate of monocotyledonous complete DNA might be reduced in the monocotyledonous cells with relatively far genetic distances. Detection results of showed that Pn in most transgenic N. tabacum with Ppc-cDNA of E. crusgalli was was higher than that in control, which preliminarily proved that PEPC of monocotyledonous plant E. crusgalli had certain regulatory effects on photosynthesis of N. tabacum.
文摘Three winter wheat cultivars ( Triticum aestivum L.), representatives of those widely cultivated in Beijing over the past six decades, were grown in the same environmental condition, and their physiological features were investigated. Daily changes of net photosynthetic rate (P-n), transpiration (T-r) in different growth stages were measured in order to find the relationship between leaf photosynthesis and yield. Instantaneous water use efficiency (WUE) of leaf was calculated from P-n/T-r. It is suggested that relationship between photosynthetic rate and yield changed with the developing stages of wheat. High yield wheat cultivar Jingdong 8 (released in the 1990s) had a higher photosynthetic rate ( the maximal P-n increased by 77%) and transpiration rate (the maximal T-r increased by 69%), but a lower WUE than the low yield cultivar Yanda 1817 (released in the 1940s) during the day time at stem elongation stage. However; difference of P-n among the three cultivars changed with wheat growth process. Before 10 o'clock P-n in leaves of Jingdong 8 usually was the highest of the three cultivars, but P-n of Yanda 1817 was the highest after 10 o'clock. At dough ripe stage, P-n in leaves of Yanda. 1817 was the highest among the three cultivars during the whole day. The difference of changing trend of transpiration in three wheat cultivars was similar to P,, but WUE of Yanda 1817 was the highest in those three cultivars, indicating that the higher yield of Jingdong 8 was achieved via a greater consumption of water. Contrary to the cultivars released in the later period, midday depression of photosynthesis was small in Yanda 1817, which might suggest that Yanda 1817 was resistant to photoinhibition. It is possible that photosynthetic potential in leaves of wheat increased as wheat cultivars was improved over the past six decades. However, it became less resistant to photoinhibition.
基金Natural Science Foundation of China (Grant No. 39900084)
文摘Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former researcher results. Then, considering some environmental factors influencing on leaf photosynthesis, three numerical sensitivity experiments were carried out. We simulated the sing le leaf net CO2 assimilation, which acts as a function of different light, carbo n dioxide and temperature conditions. The relationships between leaf net photosy nthetic rate of C3 and C4 plant with CO2 concentration intercellular, leaf tempe rature, and photosynthetic active radiation (PAR) were presented, respectively. The results show the numerical experiment may indicate the main characteristic o f plant photosynthesis in C3 and C4 plant, and further can be used to integrate with the regional climate model and act as land surface process scheme, and bett er understand the interaction between vegetation and atmosphere.
基金Foundation project： This paper is supported by the National Natural Science Foundation of China （the grant number No.39970608）.
文摘Effects of NaCI on seed germination, leaf gas exchange and seedling growth were investigated. The germination of P. tatarinowii seeds was delayed in the presence of NaCl, and was significantly inhibited when NaCl concentration exceeded 17 mM （1.0 g·L^-1）. NaCl treatments induced reductions of transpiration rate, stomatal conductance and net photosynthetic rate and their reductions were significant with the increasing of NaCl concentration. However, intercellular CO2 concentration in seedling leaves under salt stress was significantly higher than that of controls. There was a significant reduction in survival, basal diameter increment and height increment witl increasing NaCl concentration 50 days after NaCl treatment, and a significant reduction in the dry weight increment of roots, stems, and leaves was also observed in the NaCl treatments. The deleterious effect on the biomass increment was more evident in the case of stems and leaves. Results from this study suggest that P. tatarinowii is sensitive to salinity stress and the salinity threshold for seedling growth might be less 34 mM （2.0 g· L^-1）.
基金supported by the National Key Basic Research Program of China(2013CB956701)the National Natural Science Foundation of China (No.31070365)+1 种基金the project on social development of Guizhou Province (SY[2010]3043)the State Key Laboratory of Environmental Geochemistry (SKLEG2014909)
文摘The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods. Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon （COe and HCO3-） by plants. The net photosynthetic COa assimilation （PN）, the photosynthetic assimilation of CO2 and bicarbonate （PN＇）, the proportion of increased leaf area （lEA） and the stable carbon isotope composition （δ13C） of Orychophragmus violaceus （Ov） and Brassica juncea （B j） under three bicarbonate levels （5, 10 and 15 mm NaHCO3） were examined to determine the relationship among PN, PN＇ and fLA. PN＇, not PN, changed synchronously with fLA. Moreover, the proportions of exogenous bicarbonate and total bicarbonate （including exogenous bicarbonate and dissolved CO2-generated bicarbonate） utilised by Ov were 2.27 % and 5.28 % at 5 mm bicarbonate, 7.06 % and 13.28 % at 10 mm bicarbonate, and 8.55 % and 17.31% at 15 mm bicarbonate, respectively. Meanwhile, the propor- tions of exogenous bicarbonate and total bicarbonate uti- lised by Bj were 1.77 % and 3.28 % at 5 mm bicarbonate, 2.11% and 3.10 % at 10 mm bicarbonate, and 2.36 % and 3.09 % at 15 mm bicarbonate, respectively. Therefore, the dissolved CO2-generated bicarbonate and exogenous bicarbonate are important sources of inorganic carbon for plants.
基金supported by the project of the National Natural Science Foundation of China (No. 31301243)a project funded by the Priority Academic Program Development of Jiangsu higher education institutions (PAPD)+1 种基金the research foundation for introduce talents of Jiangsu university (13JDG030)the brainstorm project on social development of Guizhou Province (SY[2010]3043)
文摘The strong adaptability of Broussonetia papyrifera （L.） Vent. to low phosphorus （P） conditions can be attributed to the large amount of root-exuded organic acids and the high efficiency of P extraction. However, microelement contents are influenced by low-P stress, and their effects on the photosynthetic capability of B. pa- pyrifera remain unknown. In this study, we investigated the effects of low-P treatment on net photosynthetic rate （PN）; chlorophyll a fluorescence （ChlF） characteristics; and Fe, Mn, Cu, and Zn contents of B. papyrifera and Morus alba L. seedlings. Results show that B. papyrifera exhibited better photosynthetic capability under moderate P defi- ciency （0.125, 0.063, and 0.031 mmol/L P treatments）, whereas the photosynthetic capability of M. alba decreased under moderate and severe P deficiency （0.016 and 0 mmol/L P treatments）. Under moderate P deficiency, the decrease in Cu and Zn contents in B. papyrifera was lower than that in M. alba. Under severe P deficiency, a consid- erable decrease of photosynthetic capability in B. pa- pyrifera and M. alba was associated with low Cu and Zn contents. The PN of the two Moraceae species exhibited a better correlation with Cu and Zn contents than with Fe or Mn content. P deficiency could not only decrease cyclic photophorylation and photosynthetic efficiency, but could also affect the stability of thylakoid membrane structureand electron transport efficiency by influencing the con- tents of Cu or Zn, thereby affecting photosynthesis.
基金Supported by Natural Science Foundation of Zhejiang Province(LY13C160007)Special Fund for Graduate Innovative Projects in Jiangxi Province(YC2014-B035)Lin’an Scientific and Technological Program of Zhejiang Province(201411)
文摘The parameters of gas exchange and chlorophyl fluorescence in leaves of six rare and endangered species Neolitsea sericea, Cinnamomum japonicum var. cheni , Sinojackia microcarpa, Discocleidion glabrum var. trichocarpum, Parrotia sub-aequalis, Cercidiphyl um japonicum were measured in fields. The results showed that there were significant differences in photosynthetic capacity, intrinsic water use effi-ciency （WUEi ）, the efficiency of primary conversion of light energy of PSⅡ and its potential activity, the quantum yield of PSⅡ electron transport, and the potential ca-pacity of heat dissipation among the six species. However, there was no significant difference in WUE. The highest values of net photosynthetic rate （Pn）, transpiration rate （Tr） and stomatal conductance （gs） occurred in D. glabrum var. trichocarpum and the lowest in S. microcarpa. On the contrary, D. glabrum var. trichocarpum had the lowest WUE, intrinsic water use efficiency （WUEi ） and S. microcarpa had the highest. The results indicated that D. glabrum var. trichocarpum had higher photo-synthetic capacity and poorer WUE, while S. microcarpa had lower photosynthetic capacity and greater WUE. Furthermore, the mean values of maximal fluorescence （Fm）, potential efficiency of primary conversion of light energy of PSⅡ （Fv/Fm）,ΦPSⅡ, actual efficiency of primary conversion of light energy of PSⅡ （F′v/F′m） and non-photochemical quenching coefficient （NPQ） were the highest in S. micro-carpa, indicating that its PSⅡ had higher capacity of heat dissipation and could prevent photosynthetic apparatus from damage by excessive light energy. Correlation analysis showed that there were significant correlations among photosynthetic physi-ological parameters. However, the initial fluorescence （Fo） was not significantly cor-related with any other parameters. This study also revealed the extremely significant positive correlations between Pn and Tr, gs, apparent quantum yield （AQY）, be-tween Tr and gs, between light saturation point （LSP） and AQY, between Fv/Fm and Fm, between ΦPSⅡ and photochemical quenching coefficient （qp）, between Tr, gs and LSP, AQY. However, WUEi was significantly negatively correlated with Tr, gs, Pn, LSP and AQY.
文摘Soil pot experiments were conducted in a greenhouse to examine the effects of different nitrogen （N） supply （low, 0.15 g N/kg; middle, 0.3 g N/kg; and high, 0.6 g N/kg dry soil） on the growth, photosynthetic characteristics and photosynthetic nitrogen use efficiency （PNUE） of tobacco seedlings （Nicotiana tabacum L. Yunyan 87）. The results showed middle and high N significantly enhanced seedling growth including plant stem and leaf dry weight comparing with low N. High N supply could lead to a dramatic increase in the photosynthetic capacity of tobacco seedlings under low N conditions. There were significant differences in leaf N content between nitrogen treatments. About a 76% increase in leafN content in plants fed by high N resulted in about 43% increase in Rubisco content and 27% in net photosynthetic rate. The non-corresponding increases in photosynthetic rate in tobacco seedlings fed by high N relative to low N resulted from Rubisco activity and/or carboxylation efficiency （CE）. These results indicated that tobacco seedlings under high N application can maintain high net photosynthetic rate （Pn） but lower PNUE, will finally result in a decline in N use efficiency.
基金Supported by the Earmarked Fund for China Agriculture Research System(CARS-12)
文摘[Objective]The aim was to measure photosynthetic characters of SC 205, a cassava cultivar, and explore the relationships of the net photosynthetic rate （Pn） with physiological and ecological factors. [Method] The diurnal variations of photosyn-thesis in leaves of SC205 were studied by LICOR-6400 portable photosynthesis system, and the relationships of the net photosynthetic rate （Pn） with physiological and ecological factors were studied by simple correlation analysis and path analysis. [Result] The curve of diurnal variation of Pn showed single peak at 10：00 am at 24.07 μ mol CO2 m2/s, without showing midday depression; the diurnal changes of stomatal conductance （Gs）, transpiration rate （Tr）, leaf temperature （Tl）, air tempera-ture （Ta） and photosynthetic active radiation （PAR） al showed single peak curves, and there were positive relationships of Pn with Gs, Tr, Tl, Ta and PAR. The diur-nal variations of intercellular CO2 concentration （Ci）, atmospheric CO2 concentration （Ca）, relative humidity （RH） showed in a U-shape curve. There were highly signifi-cant positive correlation of Pn with Gs and PAR; the diurnal variation of Pn had highly significant negative correlations with Ci and Ca. The direct impact of physio-logical factors on Pn was as fol ows： Ci＆gt;Gs＆gt;Tl＆gt;Tr, and the direct impact of ecologi-cal factors was RH＆gt;PAR＆gt;Ca＆gt;Ta. [Conclusion] The research showed that Ci, Gs and Tr play very important roles in the changes of Pn among the physiological fac-tors, and PAR and Ca affect the changes of Pn among the ecological factors.
文摘In this article we consider the kth-order discrete delay survival red blood cells model. The general form of the discrete dynamical system is rewritten as Xn＋l = f（Pn,δn,xn,... ,xn＋1） where Pn,δn converge to the parametric values P and 6. We show that when the parameters are replaced by sequences, the stability results of the original system still hold.
