不同品种美国山核桃叶绿素荧光参数日变化的研究

以湖南省永州市冷水滩采穗圃中的美国山核桃为试材,研究了叶绿素荧光参数的日变化规律。结果表明:初始荧光(Fo)、最大荧光(Fm)、PSII原初光能转化效率(Fv/Fm)、光合量子产额(Yield)、光化学猝灭系数(qP)、非光化学猝灭系数(qN)和表观电子传递速率(ETR)均存在着明显的日变化。其中Fv/Fm、Fm、Yield、qP均呈先下降后上升的趋势,在中午强光下降低到最低值;qN则呈先上升后下降的趋势,在中午时分达到峰值;Fo呈下降趋势,部分品种傍晚稍有回升,但仍比早晨低;ETR日变化呈双峰曲线。不同品种间Fv/Fm、Yield、ETR、qP、qN对光强和温度的响应也存在着明显差异,可作为鉴定品种耐光抑制能力大小的指标。

Studies on the Diurnal Variation of Chlorophyll fluorescence Parameters of Different Pecan Varieties

For the field condition,we took the different pecan varieties as the samples which growing in cutting orchard in Lengshuitan,Yongzhou,Hunan.The diurnal variation of fluorescence parameters were studied.The results showed that minimal fluorescence(Fo),maximal fluorescence(Fm),optimal photochemical efficiency of photosystem II(Fv/ Fm),effective quantum yield of photosystem II(Yield),photochemical quenching coefficient(qP),non-photochemical quenching coefficient(qN)and apparent photosynthetic electron transport rate(ETR) all exhibited obvious diurnal variation.The declines in Fm,Fv/ Fm,Yield and qP were observed at midday strong sunlight.On the other hand,qN amounted to maximum value at midday.Fo decreased and some varieties went up again in the evening,but the value of evening was lower than morning.ETR varied as a two-peaked curve.Fv/ Fm,Yield,ETR,qP,qN all showed difference responded to light intensity and temperature among different pecan varieties.It can be used as the trait tolerant to photoinhibition.