To study growth responses of the roots of Panicum miliaceum L. to heterogeneous supply of nutrients. The authors analyzed the effects of the nutrient levels in both original patches (O) and destination patches (D) on ...To study growth responses of the roots of Panicum miliaceum L. to heterogeneous supply of nutrients. The authors analyzed the effects of the nutrient levels in both original patches (O) and destination patches (D) on the root growth of P. miliaceum when its roots were allowed to extend from original patch into destination patch. When the nutrient levels in the original patches were low, coarse root biomass ratio (coarse root biomass in the D/total coarse root biomass), coarse root length ratio (coarse root length in the D/total coarse root length), coarse root surface area ratio (coarse root surface area in the D/total coarse root surface area) and fine root length ratio (fine root length in the D/total fine root length) were greater in the destination patches with lower nutrient levels than in the destination patches with higher nutrient levels, while fine root length, fine root length density, fine root surface index, and fine root surface area density were smaller in the former than in the latter. When the nutrient levels in the original patches were high, fine root length, fine root length density, fine root surface area index and fine root surface density were greater in the destination patches with lower nutrient levels than in the destination patches with higher nutrient levels, coarse roots did not respond to the nutrient levels in the destination patches significantly. When the roots extended from the original patches with the same nutrient level into the destination patches with contrasting nutrient levels, fine root biomass and its percentage allocation did not respond to the nutrient levels in the destination patches significantly, whereas both root length and root surface area did. This indicates that the fine roots of P. miliaceum responded to difference in nutrient supply by plasticity in their length and surface area, rather than in their root biomass.展开更多
[Objective] This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum. [Method] Pot experiments were conducted to study the effects of atrazine stress （20, 50, 100, 200, 500 mg...[Objective] This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum. [Method] Pot experiments were conducted to study the effects of atrazine stress （20, 50, 100, 200, 500 mg/kg） on plant height, biomass, root-shoot ratio and chlorophyll content of P. hydridum. [Results] Low level of atrazine stress （20 and 50 mg/kg） showed no significant effects on plant height and biomass of P. hydridum. Moderate level of atrazine stress （100 and 200 mg/kg） did not show significant effect on plant height, but did on the biomass of P. hydridum. Biomass of P. hydridum stressed by 100 and 200 mg/kg of atrazine was decreased by 34.1% and 36.4% compared with control, respectively. High level of atrazine stress （500 mg/kg） brought significant decrease in plant height（by 40.6%） and biomass（20.0%） of P. hydridum. All levels of atrazine stress showed no significant effects on root-shoot ratio and chlorophyll content of P. hydridum. [Conclusion] Pennisetum hydridum has strong tolerance to atrazine stress.展开更多
[Objective] The aim of this study was to reveal the distribution of rapeseed clubfoot disease in Hubei Province and to assess the yield loss caused by the pathogen, Plasmodiophora brassicae. [Method] Field surveys wer...[Objective] The aim of this study was to reveal the distribution of rapeseed clubfoot disease in Hubei Province and to assess the yield loss caused by the pathogen, Plasmodiophora brassicae. [Method] Field surveys were conducted in Shayang, Dangyang, Zhijiang, Yidu and Changyang of Hubei Province during 2009- 2011. Clubfoot disease of rapeseed samples from the surveyed locations were con- firmed by PCR detection and plants infection experiment. The factors of yield and plot yields influenced by clubroot disease were determined in plot experiment. [Re- salt] Rapeseed clubroots were confirmed in Zhijiang and Dangyang and not found in Shayang and Yidu. Clubroot was found in cruciferous vegetables but not in rapeseed d in Changyang. Infection of P. brassicae significantly decreased of the first effective branch numbers of rapeseed, effective pod number per plant, seed number per pod and 1 000-grain weight. Yield of infected rapeseed decreased by 56.4% over non-infected control. [Conclusion] Rapeseed clubroot disease mainly distributed in Zhijiang and Dangyang of Hubei Province. The disease had an economic impact on rapeseed production.展开更多
Camptotheca acuminata seeds were sown in sterilized sands in the greenhouse in February of 2005. After 90-day growth, seedlings were inoculated with three species of arbuscular mycorrhizal fungi （AMF）, Acaulospora m...Camptotheca acuminata seeds were sown in sterilized sands in the greenhouse in February of 2005. After 90-day growth, seedlings were inoculated with three species of arbuscular mycorrhizal fungi （AMF）, Acaulospora mellea, Glomus diaphanum and Sclerocystis sinuosa.. The height, biomass, and absorptions of nitrogen and phosphorus of C. acuminata seedlings inoculated with AMF were investigated. The results showed that the formation of AM promoted the height growth and biomass accumulation of seedlings significantly and improved the absorption of phosphorus in seedlings. The height and biomass of mycorrhizal seedlings were 1.2 and 1.6 times higher than those of the non-mycorrhizal seedlings. The absorption of nitrogen was less influenced by the formation of AM. The nitrogen content in mycorrhizal seedling was equal to that of non-mycorrhizal seedlings. Compared with non-mycorrhizal seedlings, the nitrogen content of mycorrhizal seedlings inoculated with A. mellea changed considerably in the root, stem and leaves. The difference in nitrogen content was not significant between mycorrhizal seedlings inoculated with G. diaphanum and S. sinuosa. The AM formation stimulated the absorption of phosphorus, especially in roots, and also changed the allocation of nitrogen and phosphorus in different organs of seedlings. Compared with non-mycorrhizal seedlings, the ratio of nitrogen and phosphorus in mycorrhizal roots increased, but reduced in stem and leaves.展开更多
Nitrogen addition is rather important to the growth of alfalfa. In this study, the effects of different nitrogen application levels on various growth characteristics of alfalfa were investigated. The results showed th...Nitrogen addition is rather important to the growth of alfalfa. In this study, the effects of different nitrogen application levels on various growth characteristics of alfalfa were investigated. The results showed that nitrogen application exhibited no significant effects on plant height and stem diameter but posed significant effects on branch number of alfalfa. Branch number of alfalfa in each cutting raised with the increasing application level of nitrogen, with significant differences among different treatments （P〈0.05）; individual aboveground biomass increased with the increasing application level of nitrogen, but the increasing trend gradually tended to be steady from the first to the fourth cutting. Nitrogen application affected significantly （P〈0.05） individual aboveground biomass of alfalfa in the first, second and fourth cutting, but exhibited no significant effects on individual aboveground biomass of alfalfa in the third cutting. With the increase of nitrogen application level, total surface area, total volume, collar diameter and crossing number of alfalfa roots increased gradually, but total length, average diameter and furcating number of alfalfa roots increased first and then declined. Total length, average diameter and furcating number of alfalfa roots reached the maximum in N60 treatment.展开更多
[Objective] The aim was to study on characteristics of retoon rice yield components, and relationship of the characteristics with born bud rate and root ac- tivity of retoon rice before harvesting. [Method] Eighteen m...[Objective] The aim was to study on characteristics of retoon rice yield components, and relationship of the characteristics with born bud rate and root ac- tivity of retoon rice before harvesting. [Method] Eighteen mid-season hybrid rice va- rieties approved recently were taken as materials in high-yield cultivation conditions. Characteristics of retoon rice yield components were analyzed, and relationship of yield components characteristics with the rate of bud emergence and root activity of retoon rice before harvesting was explored, based on related data. [Result] Highly- yielding retoon rice is characterized by high effective ear number （Xl） and high set- ting percentage （X4）; the number of germinated shoots the 5^＊ d after first-batch rice was cut is a key factor for retoon rice yield and was of positive correlation with re- toon rice seedlings and effective ears, with correlation coefficients at 0.80^＊＊ and 0.76^＊＊. In addition, bleeding sap was of positive correlation with grain number and setting percentage of retoon rice and correlation coefficients were 0.50^＊ and 0.48^＊＊, and of positive correlation with average panicle weight, with correlation coefficient at 0.63. [Conclusion] It is an effective way for the rate of bud emergence and root activity at lar ecological zones. mproving retoon rice yield to increase harvesting in the test sites and simi lar ecological zones.展开更多
文摘To study growth responses of the roots of Panicum miliaceum L. to heterogeneous supply of nutrients. The authors analyzed the effects of the nutrient levels in both original patches (O) and destination patches (D) on the root growth of P. miliaceum when its roots were allowed to extend from original patch into destination patch. When the nutrient levels in the original patches were low, coarse root biomass ratio (coarse root biomass in the D/total coarse root biomass), coarse root length ratio (coarse root length in the D/total coarse root length), coarse root surface area ratio (coarse root surface area in the D/total coarse root surface area) and fine root length ratio (fine root length in the D/total fine root length) were greater in the destination patches with lower nutrient levels than in the destination patches with higher nutrient levels, while fine root length, fine root length density, fine root surface index, and fine root surface area density were smaller in the former than in the latter. When the nutrient levels in the original patches were high, fine root length, fine root length density, fine root surface area index and fine root surface density were greater in the destination patches with lower nutrient levels than in the destination patches with higher nutrient levels, coarse roots did not respond to the nutrient levels in the destination patches significantly. When the roots extended from the original patches with the same nutrient level into the destination patches with contrasting nutrient levels, fine root biomass and its percentage allocation did not respond to the nutrient levels in the destination patches significantly, whereas both root length and root surface area did. This indicates that the fine roots of P. miliaceum responded to difference in nutrient supply by plasticity in their length and surface area, rather than in their root biomass.
基金Supported by Natural Science Foundation of Yunnan Province(2010CD058)~~
文摘[Objective] This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum. [Method] Pot experiments were conducted to study the effects of atrazine stress （20, 50, 100, 200, 500 mg/kg） on plant height, biomass, root-shoot ratio and chlorophyll content of P. hydridum. [Results] Low level of atrazine stress （20 and 50 mg/kg） showed no significant effects on plant height and biomass of P. hydridum. Moderate level of atrazine stress （100 and 200 mg/kg） did not show significant effect on plant height, but did on the biomass of P. hydridum. Biomass of P. hydridum stressed by 100 and 200 mg/kg of atrazine was decreased by 34.1% and 36.4% compared with control, respectively. High level of atrazine stress （500 mg/kg） brought significant decrease in plant height（by 40.6%） and biomass（20.0%） of P. hydridum. All levels of atrazine stress showed no significant effects on root-shoot ratio and chlorophyll content of P. hydridum. [Conclusion] Pennisetum hydridum has strong tolerance to atrazine stress.
基金Supported by the Industry Technology System of Rapeseed in China(nycytx-005)Special Fund for Agro-scientific Research in the Public Interest(201003029)National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2010BAD01B04)~~
文摘[Objective] The aim of this study was to reveal the distribution of rapeseed clubfoot disease in Hubei Province and to assess the yield loss caused by the pathogen, Plasmodiophora brassicae. [Method] Field surveys were conducted in Shayang, Dangyang, Zhijiang, Yidu and Changyang of Hubei Province during 2009- 2011. Clubfoot disease of rapeseed samples from the surveyed locations were con- firmed by PCR detection and plants infection experiment. The factors of yield and plot yields influenced by clubroot disease were determined in plot experiment. [Re- salt] Rapeseed clubroots were confirmed in Zhijiang and Dangyang and not found in Shayang and Yidu. Clubroot was found in cruciferous vegetables but not in rapeseed d in Changyang. Infection of P. brassicae significantly decreased of the first effective branch numbers of rapeseed, effective pod number per plant, seed number per pod and 1 000-grain weight. Yield of infected rapeseed decreased by 56.4% over non-infected control. [Conclusion] Rapeseed clubroot disease mainly distributed in Zhijiang and Dangyang of Hubei Province. The disease had an economic impact on rapeseed production.
基金This paper was supported by the Heilongjiang Province Foundation for Distinguished Youth Scholars (JC-02-11)
文摘Camptotheca acuminata seeds were sown in sterilized sands in the greenhouse in February of 2005. After 90-day growth, seedlings were inoculated with three species of arbuscular mycorrhizal fungi （AMF）, Acaulospora mellea, Glomus diaphanum and Sclerocystis sinuosa.. The height, biomass, and absorptions of nitrogen and phosphorus of C. acuminata seedlings inoculated with AMF were investigated. The results showed that the formation of AM promoted the height growth and biomass accumulation of seedlings significantly and improved the absorption of phosphorus in seedlings. The height and biomass of mycorrhizal seedlings were 1.2 and 1.6 times higher than those of the non-mycorrhizal seedlings. The absorption of nitrogen was less influenced by the formation of AM. The nitrogen content in mycorrhizal seedling was equal to that of non-mycorrhizal seedlings. Compared with non-mycorrhizal seedlings, the nitrogen content of mycorrhizal seedlings inoculated with A. mellea changed considerably in the root, stem and leaves. The difference in nitrogen content was not significant between mycorrhizal seedlings inoculated with G. diaphanum and S. sinuosa. The AM formation stimulated the absorption of phosphorus, especially in roots, and also changed the allocation of nitrogen and phosphorus in different organs of seedlings. Compared with non-mycorrhizal seedlings, the ratio of nitrogen and phosphorus in mycorrhizal roots increased, but reduced in stem and leaves.
基金Supported by National Natural Science Foundation of China(Grant No.31372370)~~
文摘Nitrogen addition is rather important to the growth of alfalfa. In this study, the effects of different nitrogen application levels on various growth characteristics of alfalfa were investigated. The results showed that nitrogen application exhibited no significant effects on plant height and stem diameter but posed significant effects on branch number of alfalfa. Branch number of alfalfa in each cutting raised with the increasing application level of nitrogen, with significant differences among different treatments （P〈0.05）; individual aboveground biomass increased with the increasing application level of nitrogen, but the increasing trend gradually tended to be steady from the first to the fourth cutting. Nitrogen application affected significantly （P〈0.05） individual aboveground biomass of alfalfa in the first, second and fourth cutting, but exhibited no significant effects on individual aboveground biomass of alfalfa in the third cutting. With the increase of nitrogen application level, total surface area, total volume, collar diameter and crossing number of alfalfa roots increased gradually, but total length, average diameter and furcating number of alfalfa roots increased first and then declined. Total length, average diameter and furcating number of alfalfa roots reached the maximum in N60 treatment.
基金Supported by National Rice Industry Technology SystemNational Bumper-Crop Science and Technology Project(2011BAD16B05)~~
文摘[Objective] The aim was to study on characteristics of retoon rice yield components, and relationship of the characteristics with born bud rate and root ac- tivity of retoon rice before harvesting. [Method] Eighteen mid-season hybrid rice va- rieties approved recently were taken as materials in high-yield cultivation conditions. Characteristics of retoon rice yield components were analyzed, and relationship of yield components characteristics with the rate of bud emergence and root activity of retoon rice before harvesting was explored, based on related data. [Result] Highly- yielding retoon rice is characterized by high effective ear number （Xl） and high set- ting percentage （X4）; the number of germinated shoots the 5^＊ d after first-batch rice was cut is a key factor for retoon rice yield and was of positive correlation with re- toon rice seedlings and effective ears, with correlation coefficients at 0.80^＊＊ and 0.76^＊＊. In addition, bleeding sap was of positive correlation with grain number and setting percentage of retoon rice and correlation coefficients were 0.50^＊ and 0.48^＊＊, and of positive correlation with average panicle weight, with correlation coefficient at 0.63. [Conclusion] It is an effective way for the rate of bud emergence and root activity at lar ecological zones. mproving retoon rice yield to increase harvesting in the test sites and simi lar ecological zones.
