水分胁迫对美国黑莓光合特性的影响

以盆栽3年生美国黑莓(Rubussubgenusrubuswatson)植株为试材,对25%、40%、55%、70%、85%、100%6种水分胁迫条件下的光合特性进行研究。结果表明:土壤相对含水量(SRWC)为100%时,叶片的光合速率日变化呈单峰曲线;随着水分胁迫的加剧,其光合速率日变化呈双峰曲线。美国黑莓的光补偿点为50μmol/(m2.s)左右;当SRWC为25%时,其光饱和点仅为330μmol/(m2.s);当SRWC为70%以上时,光饱和点均为1 280μmol/(m2.s)左右,属喜光树种。叶片的光合速率及蒸腾速率随SRWC的升高而增加,气孔阻力随SRWC的升高而降低。光合速率与蒸腾速率呈正相关、与气孔阻力呈极显著负相关;蒸腾速率与气孔阻力呈负相关;水分利用率随着水分胁迫的增强而提高;美国黑莓的光合作用适宜SRWC为70%以上;灌溉的临界SRWC为40%。

Photosynthesis characteristics of America black raspberry in response to water stress

3-year-old potted grown plants raised by cutting of America black raspberry cutting were used as materials for studying the photosynthesis characteristics of black raspberry under the condition of six(25%、40%、55%、70%、85%、100%)artificial controlled drought gradients.The result showed under the different conditions of soil drought stress,when SRWC was 100%,the curve of diurnal variation of black raspberry leaf photosynthesis showed single peak,with the water stress developing,the curve of diurnal variation of leaf photosynthesis showed two peaks appeared at 9:00 and 15:00.Respectively the light compensation point of photosynthesis of black raspberry leaves were 50 μmol/(m2·s);when SRWC were 25%,the light saturation point were 330 μmol/(m2·s).When the SRWC 70% and over the light saturation point were 1 280 μmol/(m2·s).The leaf net photosynthesis(Pn) increased and transpiration rate increased with the raise of SRWC,the stoma resistance dropped with the raise of SRWC. Positive correlation appeared between the Pn and transpiration rate.There are a significant negative correlation between Pn and the stoma resistance.Negative correlation between the transpiration rate and the stoma resistance also existed.The water use efficiency(WUE) raised with the water stress developing.The optimum SRWC of Pn was 70% and over.The critical level of SRWC,at which the plant needs irrigation,was 40%.