极端高温干旱低海拔环境下杏光合及叶绿素荧光特性研究

【目的】探讨杏树对高温、干旱、低海拔生长环境的适应特性,为早熟杏高效栽培奠定基础。【方法】以’苏勒坦杏’和’小白杏’为试材,采用Li-6400光合仪及FMS-2脉冲调制式荧光仪,于2019年6-9月的高温季节对’苏勒坦杏’和’小白杏’叶片的光合及荧光参数的日变化趋势进行了观测,同时对杏园的环境因子进行了监测。【结果】6月份两个品种的净光合速率(Pn)和瞬时水分利用效率(RSWUE)的测定值均高于其他月份的测定值,7月测定的蒸腾速率(Tr)最高。除了’小白杏’的净光合速率(Pn)日变化曲线在9月呈"单峰"曲线外,其他月份两个品种的净光合速率(Pn)日变化曲线均呈"双峰"曲线,且其光合"午休"现象均由非气孔限制因素造成。7月份两个品种的光化学猝灭系数(CqP)、实际光化学效率(ΦPSⅡ)、最大荧光(Fm)、最大能量转换效率(Fv/Fm)、潜在光化学活性(Fv/Fo)等指标的测定值均最低,而其非光化学猝灭系数(CNPQ)和初始荧光(Fo)的测定值均最高,且与其他月份的测定值之间均有显著差异,说明7月份两个杏品种的PSII光系统的受害程度均最高。两个品种的净光合速率(Pn)与气孔导度(Gs)、蒸腾速率(Tr)、瞬时水分利用效率(RSWUE)、光合有效辐射(PAR)均呈正相关,而与胞间CO2浓度(Ci)、气孔限制值(Ls)均呈负相关关系,其与胞间CO2浓度(Ci)、气孔导度(Gs)的相关系数最高。【结论】杏树以热耗散的形式释放出过剩的能量来适应强光环境,提高蒸腾速率,从而降低叶片温度来适应高温环境;与’小白杏’相比,’苏勒坦杏’的抗光抑制能力更强,更能适应高温、强光环境。

Photosynthetic and chlorophyll fluorescence characteristics in Armeniaca vulgaris under extreme temperature,drought and low altitude conditions

【Objective】In order to lay a foundation for high efficient cultivation of early maturing Armeniaca vulgaris,adaptability of A.vulgaris trees to growing conditions of high temperature,drought and low altitude were studied.【Method】‘Suletan’and‘Xiaobaixing’were used as test materials.Daily changes of photosynthetic and fluorescence parameters of leaves were determined in high-temperature season from June to September of 2019,by using Li-6400 photosynthetic instrument and FMS-2 pulse modulation fluorescence instrument.At the same time,some environmental factors in orchard were monitored.【Result】In June,determined values of net photosynthetic rate(Pn)and instantaneous water use efficiency(RSWUE)of two varieties are higher than those in other months,and transpiration rate(Tr)is the highest in July.Except that daily change of Pn in A.vulgaris cv.‘Xiaobaixing’shows a single-peak curve in September,those of two varieties presented double-peak curves in other months,and photosynthetic“noon break”is caused by non-stomatal limiting factors.In July,determined values of photochemical quenching coefficient(CqP),actual photochemical efficiency(ΦPSⅡ),maximum fluorescence(Fm),maximum energy exchange efficiency(Fv/Fm)and potential photochemical activity(Fv/Fo)of two varieties are the lowest,and non-photochemical quenching coefficient(CNPQ)and original fluorescence(Fo)are the highest and significantly different from those in other months.It indicated that damaged degrees of PSⅡlight system of two varieties are the highest in July.net photosynthetic rate(Pn)of two varieties is positively correlated with stomatal conductance(Gs),transpiration rate(Tr),instantaneous water use efficiency(RSWUE)and photosynthetic effective radiation(PAR),and negatively correlated with intercellular CO2 concentration(Ci),stomatal limit value(Ls),and correlation coefficients of net photosynthetic rate(Pn)with intercellular CO2 concentration(Ci)and stomatal conductance(Gs)are the highest.【Conclusion】A.vulgaris trees release excess energy in the form of heat dissipation,in order to adapt to strong light environment.Transpiration rate is improved,so as to reduce leaf temperature for adapting to the high temperature environment.Resistance ability to light inhibition in A.vulgaris cv.‘Suletan’is better than that in A.vulgaris cv.‘Xiaobaixing’,so it is more suitable to grow under high temperature and strong light environment.