土壤水分对甜椒叶片某些生理特性的影响

Effects of soil moisture on physiological characteristics of sweet pepper leaves

以温室盆栽甜椒Capsicum frutescens L.为试验材料,研究了不同土壤水分下叶片的生理特性以及引起光合下降的非气孔限制因子动态特征.结果表明,随着土壤含水量的增加,叶水势(LWP)、叶鲜重含水量(FWC)、气孔导度(Gs)逐渐增加,细胞液浓度(CSC)逐渐减小;在Pn和Tr日变化进程中,最大值均出现在适宜含水量处理(65% ～75%θf)上,且Tr表现为典型双峰曲线,而其它处理的Tr和Pn均为单峰曲线.同一时段内,轻度水分胁迫(55% ～65%θf)导致光合下降主要是气孔限制引起的,重度水分胁迫(45% ～55%θf)的光合下降主要由非气孔限制引起;轻度水分胁迫使光合下降的非气孔限制出现的时间滞后,而重度水分胁迫和高水分处理(75% ～85%θf、85% ～95%θf)则使非气孔限制出现的时间提前.

Sweet pepper Capsicum frutescens L. was potted in greenhouse, and the physiological characteristics and the non-stomatal limitation factor caused photosynthesis decline under different soil moisture treatments were studied. The results showed that with the soil moisture increasing, the leaf water potential (LWP), leaf fresh weight water content (FWC) and the stomatal conductance (Gs) raised, but the cell sap concentration (CSC) decreased gradually. During the diurnal change of Pn and Tr, the maximum values emerged in the treatment of 65%-75%θ_f. The diurnal variation of Tr in the treatment of 65%-75%θ_f was demonstrated in two peaks, but the diurnal variation of Tr in other treatments and the diurnal variation of Pn in all treatments were showed in one peak. At the same time,the light water stress of 55%-65%θ_f caused the photosynthetic rate decline by means of stomatal limitation, but the heavy water stress of 45%-55%θ_f caused the photosynthetic rate to decrease due to non-stomatal limitation. The time of non-stomatal limitation emerged in the light water stress was hysteretic, but the heavy soil water stress and the higher soil water treatments of 75%-85%θ_f and 85%-95%θ_f made the time of non-stomatal limitation appear earlier.