摘要
四种作物叶片气体交换特性对水分胁迫的反应不同。高叶水势下,气孔阻力低,净光合速率是玉米>旱稻>豇豆>棉花,而蒸腾速率是棉花>豇豆>旱稻>玉米。气孔阻力对轻度水分亏缺无反应。随着水分胁迫加剧,叶水势达到某一阈值,气孔阻力突然增加。气孔开始关闭水势阈值分别为:-0.8(玉米)、-0.4(豇豆)、-1.2MPa(旱稻、棉花)。净光合速率和蒸腾速率急剧降低水势阈值分别为:玉米-0.8(P_N)和-0.7 MPa(TR),豇豆 P_N、TR 均是-0.4MPa,旱稻是-1.4和-1.1MPa,棉花是-2.0和-1.2MPa。气孔开始关闭的水势阈值和蒸腾速率急剧降低的水势阈值接近,而净光合速率急剧降低的水势阈值低于蒸腾速率急剧降低水势阈值,此时WUE 高。叶水势在-1.2MPa 以上,玉米 WUE 高于旱稻、棉花。豇豆在-0.4MPa 左右的高水势下,气孔即关闭,净光合速率和蒸腾速率均急剧降低。这可能是豇豆适应干旱方式之一。
The responses of the gas exchange characteristics of leaves of 4 different crops towater stress are different.Under high water potential and low stomatal resistance,theorder of the P_N of the crops was maize>upland rice>cowpea>cotton,whereas that ofTR was cotton>cowpea>upland rice>maize.There was no stomatal response to lowwater dificits.However,with the increase of water stress,when the ψ_W reached a certain threshold,the r_s increased suddenly.The threshold values of the initial stomatalclosure of the 4 crops were -0.8MPa(maize),-0.4MPa(cowpea),-1.2MPa(upland rice)and -1.2MPa(cotton)respectively.The threshold values ofsudden decrease of ψ_W on P_N and TR were -0.8 MPa(P_N)and -0.7 MPa(TR)for maize,-0.4MPa(P_N)and -0.4MPa(TR)for cowpea,-1.4MPa(P_N)and-1.1MPa(TR)for upland rice and -2.0MPa(P_N) and -1.2MPa(TR)forcotton.The threshold values of the initial stomatal closure were similar to those of thesudden decreases of TR,but the threshold values of the sudden decreases of P_N werelower than those of the sudden decrease of TR.The WUE was rather high at thistime.When the ψ_W values were higher than -1.2 MPa,the WUE of maize washigher than those of upland rice and cotton.The stomata of cowpea closed when theψ_W was about -0.4MPa,and both photosynthetic and transpirational activitiesdecreased suddenly.Perhaps this is one of features of adaptibility of cowpea todrought.
出处
《作物学报》
CAS
CSCD
北大核心
1990年第4期342-348,共7页
Acta Agronomica Sinica
关键词
作物
叶片
气体交换
水分胁迫
Water stress
Transpiration rate
Net photosynthesis rate
Stomatal conductance
Leaf water potential
