Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpirat...Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpiration rate and lowest LWP yielded the lowest, while TMS 91/02324 and TMS 91/02327 with intermediate rate and highest LWP yielded the highest, indicating that high transpiration rate associated with low LWP reduced yield. Transpiration was lower in the fringe with deeper water table than valley bottom at deep water table site, while at shallow water table, it was higher in the fringe than valley bottom, suggesting that drought and excess moisture reduced transpiration. LWP and water table depth correlated negatively indicating that shallow water table reduced transpiration by reducing LWP. Transpiration increased and LWP decreased as radiation, leaf temperature and vapour pressure deficit increased and differences in these microclimatic conditions caused differences in the two processes between sites, years and time of day. Under mild water stress, transpiration and LWP were higher in the afternoon than the morning, but the reverse occurred under severe stress. TMS 91/02324 and TMS 91/02327 had the highest LWP under severe stress, indicating their higher drought tolerance than the other cultivars.展开更多
Canopy temperature (CT), leaf water potential (LWP) and spikelet fertility (SF) of a set of RILs (F9) from the cross between Zhenshan97B and IRAT109 were investi- gated under two soil moisture regimes in a drought scr...Canopy temperature (CT), leaf water potential (LWP) and spikelet fertility (SF) of a set of RILs (F9) from the cross between Zhenshan97B and IRAT109 were investi- gated under two soil moisture regimes in a drought screen facility. In water stress condition, CT was negatively corre- lated with SF (r = ?0.2867) and LWP (r = ?0.2740), and LWP was positively associated with SF (r = 0.1696). These results indicated that the plant with high drought tolerant ability could maintain higher LWP and lower CT, leading to higher SF. A total of 44 main effect QTLs were associated with CT, LWP and SF. The accumulated contributionsof QTLs forCT, LWP and SF were 87.85%, 15.06%, 79.46% under well water condition and 72.61%, 87.68%, 33.29% under stress condi- tion, respectively. Totally 45 pairs of digenic interactions were detected. The accumulated contribution of digenic epistasis on CT, LWP and SF were 55.69%, 47.15%, 48.15% under well water condition and 53.44%, 57.94%, 54.62% under water stress condition. Compared with other drought tolerance QTL mapping researches in rice, 19 main effect QTLs were found to be located at the same or closely con- joint regions.展开更多
Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yieldi...Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yielding rice cultivars to moderately water-stressed upland conditions in order to contribute breeding. A three-year field experiment in the temperate climate of Kyoto, Japan, indicated that the decrease in yield was mainly derived from a decrease in above-ground total dry matter (TDM) rather than a decrease in harvest index (HI). Although the decrease in TDM was mostly caused by a decrease in radiation use efficiency (RUE), we determined that the key to adapting high-yielding cultivars to upland conditions is intercepted radiation per day (IRPD), governed by leaf area index (LAI). Although the effect was not robust, LAI growth under upland conditions was associated with root length density. RUE was dependent on leaf water potential (LWP), indicating that a plant’s ability to maintain LWP under water-stressed conditions is important. The results also suggest the necessity of a canopy analyzer to evaluate LAI, as well as an infrared radiation thermometer to evaluate RUE. Performing such measurements during breeding efforts allows us to select for genotypes that are suitable for less stressed aerobic conditions.展开更多
为了给以作物高效灌溉制度提供理论依据,对不同供水条件下冬小麦冠层温度进行了多年田间观测,模拟了以土壤水分条件为主导的冠气温差、叶水势、水分亏缺指数等的变化规律及其对影响因素的响应。结果表明,冬小麦各生育阶段不同供水处理...为了给以作物高效灌溉制度提供理论依据,对不同供水条件下冬小麦冠层温度进行了多年田间观测,模拟了以土壤水分条件为主导的冠气温差、叶水势、水分亏缺指数等的变化规律及其对影响因素的响应。结果表明,冬小麦各生育阶段不同供水处理冠层温度(T c)受土壤水分影响明显,处理间冠气温差(ΔT)差异极显著。叶水势(LW P)与ΔT、作物水分胁迫指数(CW S I)相关显著。LW P=-1.8M Pa,CW S I=0.40是指示冬小麦发生水分胁迫的关键性指标。综合各指标,为了达到节水目的,使ΔT维持在0^-4℃,可获得冬小麦产量最优值,此时冬小麦灌溉量下限应使土壤相对含水量达到58.7%。展开更多
文摘Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpiration rate and lowest LWP yielded the lowest, while TMS 91/02324 and TMS 91/02327 with intermediate rate and highest LWP yielded the highest, indicating that high transpiration rate associated with low LWP reduced yield. Transpiration was lower in the fringe with deeper water table than valley bottom at deep water table site, while at shallow water table, it was higher in the fringe than valley bottom, suggesting that drought and excess moisture reduced transpiration. LWP and water table depth correlated negatively indicating that shallow water table reduced transpiration by reducing LWP. Transpiration increased and LWP decreased as radiation, leaf temperature and vapour pressure deficit increased and differences in these microclimatic conditions caused differences in the two processes between sites, years and time of day. Under mild water stress, transpiration and LWP were higher in the afternoon than the morning, but the reverse occurred under severe stress. TMS 91/02324 and TMS 91/02327 had the highest LWP under severe stress, indicating their higher drought tolerance than the other cultivars.
基金This study was supported by the Hi-Technology Research and Development Program of China(Grant No.2003AA207010)the National Basic Research Program of China(Grant No.2004CB 117204)..
文摘Canopy temperature (CT), leaf water potential (LWP) and spikelet fertility (SF) of a set of RILs (F9) from the cross between Zhenshan97B and IRAT109 were investi- gated under two soil moisture regimes in a drought screen facility. In water stress condition, CT was negatively corre- lated with SF (r = ?0.2867) and LWP (r = ?0.2740), and LWP was positively associated with SF (r = 0.1696). These results indicated that the plant with high drought tolerant ability could maintain higher LWP and lower CT, leading to higher SF. A total of 44 main effect QTLs were associated with CT, LWP and SF. The accumulated contributionsof QTLs forCT, LWP and SF were 87.85%, 15.06%, 79.46% under well water condition and 72.61%, 87.68%, 33.29% under stress condi- tion, respectively. Totally 45 pairs of digenic interactions were detected. The accumulated contribution of digenic epistasis on CT, LWP and SF were 55.69%, 47.15%, 48.15% under well water condition and 53.44%, 57.94%, 54.62% under water stress condition. Compared with other drought tolerance QTL mapping researches in rice, 19 main effect QTLs were found to be located at the same or closely con- joint regions.
文摘Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yielding rice cultivars to moderately water-stressed upland conditions in order to contribute breeding. A three-year field experiment in the temperate climate of Kyoto, Japan, indicated that the decrease in yield was mainly derived from a decrease in above-ground total dry matter (TDM) rather than a decrease in harvest index (HI). Although the decrease in TDM was mostly caused by a decrease in radiation use efficiency (RUE), we determined that the key to adapting high-yielding cultivars to upland conditions is intercepted radiation per day (IRPD), governed by leaf area index (LAI). Although the effect was not robust, LAI growth under upland conditions was associated with root length density. RUE was dependent on leaf water potential (LWP), indicating that a plant’s ability to maintain LWP under water-stressed conditions is important. The results also suggest the necessity of a canopy analyzer to evaluate LAI, as well as an infrared radiation thermometer to evaluate RUE. Performing such measurements during breeding efforts allows us to select for genotypes that are suitable for less stressed aerobic conditions.
文摘为了给以作物高效灌溉制度提供理论依据,对不同供水条件下冬小麦冠层温度进行了多年田间观测,模拟了以土壤水分条件为主导的冠气温差、叶水势、水分亏缺指数等的变化规律及其对影响因素的响应。结果表明,冬小麦各生育阶段不同供水处理冠层温度(T c)受土壤水分影响明显,处理间冠气温差(ΔT)差异极显著。叶水势(LW P)与ΔT、作物水分胁迫指数(CW S I)相关显著。LW P=-1.8M Pa,CW S I=0.40是指示冬小麦发生水分胁迫的关键性指标。综合各指标,为了达到节水目的,使ΔT维持在0^-4℃,可获得冬小麦产量最优值,此时冬小麦灌溉量下限应使土壤相对含水量达到58.7%。
