Effect of intermittent irrigation on the production of paddy rice was studied in a well-puddled paddy field with four treatments and 2 replicates: continuous flooding irrigation (CFI), and intermittent irrigation Ⅱ-...Effect of intermittent irrigation on the production of paddy rice was studied in a well-puddled paddy field with four treatments and 2 replicates: continuous flooding irrigation (CFI), and intermittent irrigation Ⅱ-O, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Results showed that the reduction in soil water potential to about -10 or -20 kPa did not significantly affect the number of grains and the percentage of ripened grains. While, a lower crop growth rate (CGR) resulted from a decrease in the net assimilation rate (NAR) during intermittent irrigation Ⅱ-1 and Ⅱ-2, and there was also a reduction in the leaf area index (LAI) during intermittent irrigation Ⅱ-2. Senescence of lower leaves on stems was promoted in treatments Ⅱ-1 and Ⅱ-2 at the ripening stage. Early senescence at ripening stage and water stress around midday decreased the rate of photosynthesis in leaves, causing the lower NAR. These physiological responses of the plants were responsible for the reduction in the dry matter production and grain yield in the intermittent irrigation treatments.展开更多
The prevalence of insect pests was studied on rice BRI 1 （mukta） as understory crop grown in association with 11 years old selected tree species viz, Akashmoni. Jhau and Albida in the field laboratory of the Departm...The prevalence of insect pests was studied on rice BRI 1 （mukta） as understory crop grown in association with 11 years old selected tree species viz, Akashmoni. Jhau and Albida in the field laboratory of the Department of Agroforestry, Bangladesh Agricultural University （BAU）. Mymensingh during the period from July to December, 2003. Among the three species Albida and Jhau possessed the largest canopy and there light penetration rate were high. On the other hand. Akashmoni had the lowest canopy but it penetrated low amount of light. Albida-rice association showed the lowest infestation of major rice insects followed by Jhau-rice association, while Akashmoni-rice association showed the highest insect infestation. Light intensity in the control plot （absent of tree species） was maximum and it caused minimum severity of insects infestation as compared to other associations. From the result it appeared that light interception has the relationship with insect population in rice. Therefore, tree species having sparse canopy which allowed easy penetration of sunlight is suitable for tree-flee agroforestry system.展开更多
A field study was conducted at CRIN Uhonmora Substation, Edo State in Derived Guinea Savanna Zone of Nigeria between 2007 and 2008. The experiment determined influence of intercropping cocoa with rice and plantain at ...A field study was conducted at CRIN Uhonmora Substation, Edo State in Derived Guinea Savanna Zone of Nigeria between 2007 and 2008. The experiment determined influence of intercropping cocoa with rice and plantain at early stage of field establishment. Four treatments considered were cocoa （sole）, cocoa/rice, cocoa/plantain and cocoa/rice/plantain. Spacing of 3.1 m apart was used for cocoa and plantain while rice was 30 cm. Plot laid out was randomized complete block design replicated three times. Data on cocoa morphological parameters comprising plant height, girth and leaf area as well as weed biomass were measured monthly. Cocoa survival count was also determined. Data collected were subjected to ANOVA, and LSD was used to separate the means. Survival count showed over 95% survival in all treatments without any significance differences. On plant height and leaf area vegetative growth were significantly higher （P 〈 0.05） in the intercrops than the sole cocoa but not significantly different in all the months. Plant vigour was significantly higher in cocoa/plantain intercrop. Cocoa/rice/plantain produced the least weed biomass while cocoa sole gave the highest. Therefore, cocoa/rice and cocoa/plantain intercrops could be recommended to cocoa farmers in Nigeria instead of sole planting at early age of field establishment.展开更多
Photoperiod and temperature are two pivotal regulatory factors of plant flowering. The floral transition of plants depends on accurate measurement of changes in photoperiod and temperature. The flowering time of rice ...Photoperiod and temperature are two pivotal regulatory factors of plant flowering. The floral transition of plants depends on accurate measurement of changes in photoperiod and temperature. The flowering time of rice （Oryza sativa） as a facultative short-day （SD） plant is delayed under long-day （LD） and/or low temperature conditions. To elucidate the regulatory functions of photoperiod and temperature on flowering time in rice, we systematically analyzed the expression and regulation of several key genes （Hd3a, RFT1, Ehdl, Ghd7, RID1/Ehd2/OsIdl, Se5） involved in the photoperiodic flowering regulatory pathway under different temperature and photoperiod treatments using a photoperiod-insensitive mutant and wild type plants. Our re- sults indicate that the Ehdl-Hd3a/RFT1 pathway is common to and conserved in both the photoperiodic and temperature flow- ering regulatory pathways. Expression of Ehdl, Hd3a and RFT1 is dramatically reduced at low temperature （23~C）, suggesting that suppression of Ehdl, Hd3a and RFT1 transcription is an essential cause of delayed flowering under low temperature con- dition. Under LD condition, Ghd7 mRNA levels are promoted at low temperature （23~C） compared with normal temperature condition （28℃）, suggesting low temperature and LD treatment have a synergistic role in the expression of Ghd7. Therefore, upregulation of Ghd7 might be a crucial cause of delayed flowering under low temperature condition. We also analyzed Hdl regulatory relationships in the photoperiodic flowering pathway, and found that Hdl can negatively regulate Ehdl transcription under LD condition. In addition, Hdl can also positively regulate Ghd7 transcription under LD condition, suggesting that the heading-date of rice under LD condition is also regulated by the Hdl-Ghd7-Ehdl-RFT1 pathway.展开更多
基金Project (No. 49971043) supported partly by the National Natural Science Foundation of China.
文摘Effect of intermittent irrigation on the production of paddy rice was studied in a well-puddled paddy field with four treatments and 2 replicates: continuous flooding irrigation (CFI), and intermittent irrigation Ⅱ-O, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Results showed that the reduction in soil water potential to about -10 or -20 kPa did not significantly affect the number of grains and the percentage of ripened grains. While, a lower crop growth rate (CGR) resulted from a decrease in the net assimilation rate (NAR) during intermittent irrigation Ⅱ-1 and Ⅱ-2, and there was also a reduction in the leaf area index (LAI) during intermittent irrigation Ⅱ-2. Senescence of lower leaves on stems was promoted in treatments Ⅱ-1 and Ⅱ-2 at the ripening stage. Early senescence at ripening stage and water stress around midday decreased the rate of photosynthesis in leaves, causing the lower NAR. These physiological responses of the plants were responsible for the reduction in the dry matter production and grain yield in the intermittent irrigation treatments.
文摘The prevalence of insect pests was studied on rice BRI 1 （mukta） as understory crop grown in association with 11 years old selected tree species viz, Akashmoni. Jhau and Albida in the field laboratory of the Department of Agroforestry, Bangladesh Agricultural University （BAU）. Mymensingh during the period from July to December, 2003. Among the three species Albida and Jhau possessed the largest canopy and there light penetration rate were high. On the other hand. Akashmoni had the lowest canopy but it penetrated low amount of light. Albida-rice association showed the lowest infestation of major rice insects followed by Jhau-rice association, while Akashmoni-rice association showed the highest insect infestation. Light intensity in the control plot （absent of tree species） was maximum and it caused minimum severity of insects infestation as compared to other associations. From the result it appeared that light interception has the relationship with insect population in rice. Therefore, tree species having sparse canopy which allowed easy penetration of sunlight is suitable for tree-flee agroforestry system.
文摘A field study was conducted at CRIN Uhonmora Substation, Edo State in Derived Guinea Savanna Zone of Nigeria between 2007 and 2008. The experiment determined influence of intercropping cocoa with rice and plantain at early stage of field establishment. Four treatments considered were cocoa （sole）, cocoa/rice, cocoa/plantain and cocoa/rice/plantain. Spacing of 3.1 m apart was used for cocoa and plantain while rice was 30 cm. Plot laid out was randomized complete block design replicated three times. Data on cocoa morphological parameters comprising plant height, girth and leaf area as well as weed biomass were measured monthly. Cocoa survival count was also determined. Data collected were subjected to ANOVA, and LSD was used to separate the means. Survival count showed over 95% survival in all treatments without any significance differences. On plant height and leaf area vegetative growth were significantly higher （P 〈 0.05） in the intercrops than the sole cocoa but not significantly different in all the months. Plant vigour was significantly higher in cocoa/plantain intercrop. Cocoa/rice/plantain produced the least weed biomass while cocoa sole gave the highest. Therefore, cocoa/rice and cocoa/plantain intercrops could be recommended to cocoa farmers in Nigeria instead of sole planting at early age of field establishment.
基金supported by the National Natural Science Foundation of China (Grant Nos. 31171515 and 30871328)Tianjin Natural Science Foundation of China (Grant No. 11JCZDJC17900)+1 种基金the Program of Tian-jin Municipal Education Commission (Grant No. 20090609)Knowledge Innovation Program of Tianjin Normal University (Grant No. 52X09039)
文摘Photoperiod and temperature are two pivotal regulatory factors of plant flowering. The floral transition of plants depends on accurate measurement of changes in photoperiod and temperature. The flowering time of rice （Oryza sativa） as a facultative short-day （SD） plant is delayed under long-day （LD） and/or low temperature conditions. To elucidate the regulatory functions of photoperiod and temperature on flowering time in rice, we systematically analyzed the expression and regulation of several key genes （Hd3a, RFT1, Ehdl, Ghd7, RID1/Ehd2/OsIdl, Se5） involved in the photoperiodic flowering regulatory pathway under different temperature and photoperiod treatments using a photoperiod-insensitive mutant and wild type plants. Our re- sults indicate that the Ehdl-Hd3a/RFT1 pathway is common to and conserved in both the photoperiodic and temperature flow- ering regulatory pathways. Expression of Ehdl, Hd3a and RFT1 is dramatically reduced at low temperature （23~C）, suggesting that suppression of Ehdl, Hd3a and RFT1 transcription is an essential cause of delayed flowering under low temperature con- dition. Under LD condition, Ghd7 mRNA levels are promoted at low temperature （23~C） compared with normal temperature condition （28℃）, suggesting low temperature and LD treatment have a synergistic role in the expression of Ghd7. Therefore, upregulation of Ghd7 might be a crucial cause of delayed flowering under low temperature condition. We also analyzed Hdl regulatory relationships in the photoperiodic flowering pathway, and found that Hdl can negatively regulate Ehdl transcription under LD condition. In addition, Hdl can also positively regulate Ghd7 transcription under LD condition, suggesting that the heading-date of rice under LD condition is also regulated by the Hdl-Ghd7-Ehdl-RFT1 pathway.
