Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is availabl...Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is available for the model plant, Arabidopsis, whose adoption has great significance for further probing the molecular aspects of long distance stress signals. Here, we introduced the es- tablishment of techniques for investigations of root to shoot signals in Arabidopsis. Stomata! movements in relation to root signals were probed by using these techniques. The results show that Arabidopsis is a suitable plant species for partial roots drying （PRD） experiments. In the PRD system, while no significant differences were found in leaf water potential between well-watered and stressed plants, water stress led to a decrease in leaf conductance, which suggests a regulation of stomatal movements by root to shoot signals. While water stress caused a significant increase in the concentration of sap abscisic acid （ABA） of xylem, no increase in xylem sap pH was observed. Moreover, the increase in the ABA content of xylem coincided with the decrease in leaf conductance, which suggests a possible role of ABA in the regulation of stomatal movements. Infrared temperature images showed that leaf tem- peratures of PRD plant were higher compared with those of well-watered plants, which further indicates that stomatal movements can be modulated by root signals. The confirmation of root to shoot signaling in Arabidopsis has established a basis for further inves- tigation into the molecular mechanisms of the root to shoot signaling under water stress.展开更多
Increasing leaf photosynthesis per area（A） is of great importance to achieve yield further improvement. The aim of this study was to exploit varietal difference in A and its correlation with specific leaf weight（SL...Increasing leaf photosynthesis per area（A） is of great importance to achieve yield further improvement. The aim of this study was to exploit varietal difference in A and its correlation with specific leaf weight（SLW）. Twelve rice cultivars, including 6 indica and 6 japonica varieties, were pot-grown under two N treatments, low N（LN） and sufficient N（SN）. Leaf photosynthesis and related parameters were measured at tillering stage. Compared with LN treatment, A, stomatal conductance（g_s）, mesophyll conductance（g_m）, leaf N content（N_（area））, and chlorophyll content were significantly improved under SN treatment, while SLW and photosynthetic N use efficiency（PNUE） were generally decreased. Varietal difference in A was positively related to both g_s and g_m, but not related to N_（area）. This resulted in a low PNUE in high N_（area） leaves. Varietal difference in PNUE was generally negatively related to SLW. Response of PNUE to N supply varied among different rice cultivars, and interestingly, the decrease in PNUE under SN was negatively related to the decrease in SLW. With a higher N_（area）, japonica rice cultivars did not show a higher A than indica rice cultivars because of possession of high-SLW leaves. Therefore, varietal difference in A was not related to N_（area）, and SLW can substantially interfere with the correlation between A and N_（area）. These findings may provide useful information for rice breeders to maximize A and PNUE, rather than over reliance on N_（area） as an indicator of photosynthetic performance.展开更多
Effect of different shading levels (no-shading, 80% shading, and 40% shading) on photosynthetic and stomatal responses in cotton leaves were investigated under conditions of different soil water contents in summer mid...Effect of different shading levels (no-shading, 80% shading, and 40% shading) on photosynthetic and stomatal responses in cotton leaves were investigated under conditions of different soil water contents in summer midday. All cotton leaves exhibited similar basic responses to shading, including decreased net photosynthetic rates, a tendency to decrease in transpiration rates, and increased stomatal conductance and intercellular CO2 concentration. The leaf conductance of 80% shaded and 40% shaded plants increased by 28% and 16.7% compared with no-shaded plants at high water, respectively, but the net photosynthetic rates of 80% shaded and 40% shaded plants declined by 50% and 14.73%, respectively. Results showed that combined effect of soil moisture and shading on photosynthetic and stomatal responses in cotton leaves was very remarkable.展开更多
Hydraulic theory predicts a positive coupling between leaf hydraulic conductance(K_(leaf))and stomatal conductance(g_(s));however,this theory has not been fully supported by observations,and underlying mechanisms are ...Hydraulic theory predicts a positive coupling between leaf hydraulic conductance(K_(leaf))and stomatal conductance(g_(s));however,this theory has not been fully supported by observations,and underlying mechanisms are poorly understood.Partitioning K_(leaf)into inside-xylem(K_(x))and outside-xylem(K_(ox))components offers a refined framework for elucidating the regulation of g_(s) by leaf hydraulics.While optimal planting density may enhance water use efficiency(WUE)through modulation of g_(s),corresponding changes in leaf hydraulic properties and their influence on gas exchange remain unclear.We examined relationships among K_(x),K_(ox),g_(s),leaf photosynthetic rate(A_(N)),and WUE,and analyzed the structural determinants of K_(ox)in cotton grown under eight planting densities:12,18,24,36,48,60,72,and 84 plants m^(–2).Results showed that as planting density increased,K_(leaf)and A_(N) remained stable,whereas K_(ox)and g_(s) declined significantly.Leaf thickness and the volume fraction of inter-cellular air space were key structural factors influencing K_(ox).Neither K_(leaf)nor K_(x)correlated with A_(N) or g_(s);however,K_(ox)exhibited a significant positive correlation with g_(s).Furthermore,K_(ox)was negatively correlated with WUE.These findings indicate that K_(ox)modulates g_(s) to minimize water loss without compromising A_(N),thereby enhancing WUE in cotton across varying planting densities.展开更多
The systematic or long-distance signal transmission plays crucial roles inanimal lives.Compared with animals,however,much less is known about the roles of long-distancesignal communication in plant lives.Using the mod...The systematic or long-distance signal transmission plays crucial roles inanimal lives.Compared with animals,however,much less is known about the roles of long-distancesignal communication in plant lives.Using the model plant Commelina communisL,we have probed theroot to shoot communication mediated by heat-shock signals.The results showed that a heat shock of5 min at 40°C in partial roots,i.e.half or even 1/4 root system,could lead to a significantdecrease in stomatal conductance.The regulation capability depends on both heat shock temperatureand the amount of root system,i.e.with higher temperature and more roots stressed,the leafconductance would decrease more significantly.Interestingly,the stomatal regulation by heat shocksignal is in a manner of oscillation:when stomata conductance decreased to the lowest level withinabout 30 min,it would increase rapidly and sometimes even exceed the initial level,and afterseveral cycles the stomata conductance would be finallystabilized at a lower level.Feeding xylemsap collected from heat-shocked plants could lead to a decrease in stomata conductance,suggestingthat the heat shock-initiated signal is basically a positive signal.Further studies showed thatheat shock wasnot able to affect ABA content in xylem sap,and also,not able to lead to a decreasein leaf water status,which suggested that the stomatal regulation was neither mediated by ABA norby a hydraulic signal.Heat shock could lead to an increase in xylemsap H_2O_(2)content,andmoreover,the removal of H_2O_(2)by catalase could partially recover the stomatal inhibition by xylemsap collected from heat-shocked plants,suggesting that H_2O_(2)might be able to act as one of theroot signals to control the stomatal movement.Due to the fact that heat-shock and drought areusually two concomitant stresses,the stomatal regulation by heat-shock signal should be ofsignificance for plant response to stresses.The observation for the stomatal regulation in anoscillation manner by presently identified new signals should contribute to further understanding ofthe mystery for the pant systematic signaling in response to stresses.展开更多
文摘Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is available for the model plant, Arabidopsis, whose adoption has great significance for further probing the molecular aspects of long distance stress signals. Here, we introduced the es- tablishment of techniques for investigations of root to shoot signals in Arabidopsis. Stomata! movements in relation to root signals were probed by using these techniques. The results show that Arabidopsis is a suitable plant species for partial roots drying （PRD） experiments. In the PRD system, while no significant differences were found in leaf water potential between well-watered and stressed plants, water stress led to a decrease in leaf conductance, which suggests a regulation of stomatal movements by root to shoot signals. While water stress caused a significant increase in the concentration of sap abscisic acid （ABA） of xylem, no increase in xylem sap pH was observed. Moreover, the increase in the ABA content of xylem coincided with the decrease in leaf conductance, which suggests a possible role of ABA in the regulation of stomatal movements. Infrared temperature images showed that leaf tem- peratures of PRD plant were higher compared with those of well-watered plants, which further indicates that stomatal movements can be modulated by root signals. The confirmation of root to shoot signaling in Arabidopsis has established a basis for further inves- tigation into the molecular mechanisms of the root to shoot signaling under water stress.
基金supported by the National Natural Science Foundation of China(31301840)the National Excellent Doctoral Dissertation of China(201465)+2 种基金the Program for Changjiang Scholars and Innovative Research Team in University of China(IRT1247)the Natural Science Foundation of Hubei Province,China(2013CFB201)the Fundamental Research Funds for the Central Universities,China(2013PY107)
文摘Increasing leaf photosynthesis per area（A） is of great importance to achieve yield further improvement. The aim of this study was to exploit varietal difference in A and its correlation with specific leaf weight（SLW）. Twelve rice cultivars, including 6 indica and 6 japonica varieties, were pot-grown under two N treatments, low N（LN） and sufficient N（SN）. Leaf photosynthesis and related parameters were measured at tillering stage. Compared with LN treatment, A, stomatal conductance（g_s）, mesophyll conductance（g_m）, leaf N content（N_（area））, and chlorophyll content were significantly improved under SN treatment, while SLW and photosynthetic N use efficiency（PNUE） were generally decreased. Varietal difference in A was positively related to both g_s and g_m, but not related to N_（area）. This resulted in a low PNUE in high N_（area） leaves. Varietal difference in PNUE was generally negatively related to SLW. Response of PNUE to N supply varied among different rice cultivars, and interestingly, the decrease in PNUE under SN was negatively related to the decrease in SLW. With a higher N_（area）, japonica rice cultivars did not show a higher A than indica rice cultivars because of possession of high-SLW leaves. Therefore, varietal difference in A was not related to N_（area）, and SLW can substantially interfere with the correlation between A and N_（area）. These findings may provide useful information for rice breeders to maximize A and PNUE, rather than over reliance on N_（area） as an indicator of photosynthetic performance.
基金Project (No. 49725102) supported by the National Outstanding Youth Science Foundation of China.
文摘Effect of different shading levels (no-shading, 80% shading, and 40% shading) on photosynthetic and stomatal responses in cotton leaves were investigated under conditions of different soil water contents in summer midday. All cotton leaves exhibited similar basic responses to shading, including decreased net photosynthetic rates, a tendency to decrease in transpiration rates, and increased stomatal conductance and intercellular CO2 concentration. The leaf conductance of 80% shaded and 40% shaded plants increased by 28% and 16.7% compared with no-shaded plants at high water, respectively, but the net photosynthetic rates of 80% shaded and 40% shaded plants declined by 50% and 14.73%, respectively. Results showed that combined effect of soil moisture and shading on photosynthetic and stomatal responses in cotton leaves was very remarkable.
基金financially supported by the Tianshan Talent Development Program,China for Yali Zhangthe Natural Science Foundation of Xinjiang Production and Construction Corps,China(2024DA002)the Earmarked Fund for XJARS-Cotton,China(XJARS-03)。
文摘Hydraulic theory predicts a positive coupling between leaf hydraulic conductance(K_(leaf))and stomatal conductance(g_(s));however,this theory has not been fully supported by observations,and underlying mechanisms are poorly understood.Partitioning K_(leaf)into inside-xylem(K_(x))and outside-xylem(K_(ox))components offers a refined framework for elucidating the regulation of g_(s) by leaf hydraulics.While optimal planting density may enhance water use efficiency(WUE)through modulation of g_(s),corresponding changes in leaf hydraulic properties and their influence on gas exchange remain unclear.We examined relationships among K_(x),K_(ox),g_(s),leaf photosynthetic rate(A_(N)),and WUE,and analyzed the structural determinants of K_(ox)in cotton grown under eight planting densities:12,18,24,36,48,60,72,and 84 plants m^(–2).Results showed that as planting density increased,K_(leaf)and A_(N) remained stable,whereas K_(ox)and g_(s) declined significantly.Leaf thickness and the volume fraction of inter-cellular air space were key structural factors influencing K_(ox).Neither K_(leaf)nor K_(x)correlated with A_(N) or g_(s);however,K_(ox)exhibited a significant positive correlation with g_(s).Furthermore,K_(ox)was negatively correlated with WUE.These findings indicate that K_(ox)modulates g_(s) to minimize water loss without compromising A_(N),thereby enhancing WUE in cotton across varying planting densities.
基金supported by the National Basic Research Program of China(Grant No.2003CB114300)National Natural Science Foundation of China(Grant Nos.30270135&30470160).
文摘The systematic or long-distance signal transmission plays crucial roles inanimal lives.Compared with animals,however,much less is known about the roles of long-distancesignal communication in plant lives.Using the model plant Commelina communisL,we have probed theroot to shoot communication mediated by heat-shock signals.The results showed that a heat shock of5 min at 40°C in partial roots,i.e.half or even 1/4 root system,could lead to a significantdecrease in stomatal conductance.The regulation capability depends on both heat shock temperatureand the amount of root system,i.e.with higher temperature and more roots stressed,the leafconductance would decrease more significantly.Interestingly,the stomatal regulation by heat shocksignal is in a manner of oscillation:when stomata conductance decreased to the lowest level withinabout 30 min,it would increase rapidly and sometimes even exceed the initial level,and afterseveral cycles the stomata conductance would be finallystabilized at a lower level.Feeding xylemsap collected from heat-shocked plants could lead to a decrease in stomata conductance,suggestingthat the heat shock-initiated signal is basically a positive signal.Further studies showed thatheat shock wasnot able to affect ABA content in xylem sap,and also,not able to lead to a decreasein leaf water status,which suggested that the stomatal regulation was neither mediated by ABA norby a hydraulic signal.Heat shock could lead to an increase in xylemsap H_2O_(2)content,andmoreover,the removal of H_2O_(2)by catalase could partially recover the stomatal inhibition by xylemsap collected from heat-shocked plants,suggesting that H_2O_(2)might be able to act as one of theroot signals to control the stomatal movement.Due to the fact that heat-shock and drought areusually two concomitant stresses,the stomatal regulation by heat-shock signal should be ofsignificance for plant response to stresses.The observation for the stomatal regulation in anoscillation manner by presently identified new signals should contribute to further understanding ofthe mystery for the pant systematic signaling in response to stresses.
