平茬年限对沙冬青光合特性与比叶面积的影响

[目的]为在理论与技术上解决孑遗植物种质资源的保存与修复,探究沙冬青被平茬后更新恢复生长的机理和策略.[方法]利用Li-6400便携式光合仪测定了不同平茬年限沙冬青的光合生理特性,同时分析了不同平茬年限沙冬青比叶面积(SLA)与光合速率(Pn)、水分利用效率(WUE)的关系,从而更好地解释平茬复壮后植物补偿性生长机理与...

Effect of pruning years on photosynthetic characteristic and specific leaf area of Ammopiptanthus mongolicus

【Objective】It is helpful to solve the technical problems of conservation and development of the germplasm resources in theory and technology.The study on the mechanism and strategy of regeneration and restoration of Ammopiptanthus mongolicus after stubble.【Method】The photosynthetic characteristics of A.mongolicus at different pruning years were determined by Li-6400 portable photosynthetic apparatus.At the same time,the relationship between specific leaf area(SLA)of A.mongolicus and the net photosynthetic rate(Pn),water use efficiency(WUE)was analyzed at different pruning years.So it can better explain the compensatory growth mechanism and duration of plants after rejuvenation of stubble.【Result】The diurnal variation of net photosynthetic rate and transpiration rate of A.mongolicus at different pruning years had a bimodal curve excepted one year after rejuvenation pruning of A.mongolicus,which had a single-peak curve.The maximum value appeared around 11:00,and the second peak value appeared around 15:00.The diurnal variation trend of water use efficiency at different pruning years of stubble also showed a single-peak curve or bimodal curve,but the time of peak appeared were differences at different pruning years.With the increase of the pruning years,the recovery growth rate slowed down,and the net photosynthetic rate,transpiration rate and water use efficiency also decreased.The order of the average diurnal variation flowed by one year after rejuvenation pruning>three years after rejuvenation pruning>eight years after rejuvenation pruning>controlled plant.The difference of specific leaf area in different pruning years was significant(P<0.05),and the specific leaf area decreased with the increase of pruning years.There was significant positive correlation between specific leaf area and net photosynthetic rate at different pruning years.However,specific leaf area and water use efficiency(WUE)existed a significant negative correlation relationship.With the increasing pruning years,the slope of regression equation gradually decreased,so net photosynthetic rate and water use efficiency of A.mongolicus gradually reduced.【Conclusion】Therefore,it was necessary to promote stand rejuvenation and growth by reasonably leveling the stubble of aged and dried A.mongolicus,and improving productivity was conducive to promoting effective recovery of desert ecosystem.