低温胁迫对凹叶厚朴光合特性和相关生理指标的影响

Effect of Low Temperature Stress on Photosynthesis Physiology of Magnolia officinalis subsp.biloba

以2年生凹叶厚朴幼苗为试材,研究了在不同低温胁迫(-5、0、5、10、15℃,以25℃为对照)下凹叶厚朴生理指标和光合特性的变化。结果表明:随着胁迫温度降低,凹叶厚朴幼苗叶绿素含量下降,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)逐步降低,光合PSⅡ最大光化学效率(Fv/Fm)、潜在光化学效率(Fv/Fo)、表观电子传递速率(ETR)、光合量子产额(Yield)、光化学淬灭系数(qP)总体呈现递减趋势,而胞间CO2浓度(Ci)、丙二醛(MDA)含量、细胞质膜透性、非光化学淬灭系数(NPQ)呈上升趋势,质膜在-5℃时受损最严重,大量离子外渗。低温使叶绿素显著降低,PSⅡ反应中心受损,对凹叶厚朴幼苗产生显著光抑制,导致光合作用能力降低。

The 2-year-old Magnolia officinalis was used as test material,the photosynthetic characteristics of-5,0,5,10,15,25 ℃（CK）were studied by artificial low temperature stress.The results showed that the net photosynthetic rate（Pn）,stomatal conductance（Gs）and transpiration rate（Tr）decreased gradually with the decrease of stress temperature,the decrease of chlorophyll content.The highest photo-chemical efficiency（Fv/Fm）,potential photo-chemical efficiency（Fv/Fo）,apparent electron transport rate（ETR）,photosynthetic quantum yield（Yield）and photo-chemical quenching coefficient（qP）of photosynthetic PSII showed a decreasing trend.Ci,malondialdehyde（MDA）content,cytoplasmic membrane permeability and non-photo-chemical quenching coefficient（NPQ）increased,then plasma membrane was the most serious damage at-5 ℃,a large number of ion percolated.Low temperature of chlorophyll significantly reduced,PSII reaction center damage,the leaves of Magnolia officinalis seedlings significantly inhibited light,resulting in reduced photosynthetic capacity.