摘要
以3年生山杏苗木为材料,用CIRAS-2型光合仪测定70%和40%遮光处理下其叶片光合生理参数的光响应和日变化特征,以探讨山杏光合特性对光照条件的适应机制。结果表明:(1)随着遮光处理的加重,山杏叶片净光合速率(Pn)、光补偿点、光饱和点、暗呼吸速率及生物量等均呈下降趋势,70%和40%遮光处理下山杏叶片最大Pn分别比全光照显著下降58%和38%,而其表观量子效率分别显著提高31%和22%。(2)遮光处理下,山杏叶片Pn日变化呈"单峰"曲线,70%和40%遮光处理山杏叶片Pn日均值分别比全光照显著下降68%和49%;随着环境光照的增强,山杏叶片Pn下降的原因逐渐由气孔限制转变为非气孔限制为主。(3)随光照强度的增加,山杏叶片蒸腾速率表现为增大趋势,70%和40%遮光处理的均值分别比全光照下降55%和16%;弱光环境下山杏具有降低蒸腾作用来提高水分利用效率的生理特性,水分利用效率均值和最大值均表现为70%遮光>全光照>40%遮光。研究发现,山杏较喜光,但对弱光也有一定适应能力,光照生态幅较宽,在干旱缺水的黄土丘陵区适当遮荫可提高其对有限水分的利用效率。
In order to obtain the photosynthetic characteristics adaptability of Prunus sibirica L.to different light conditions,we measured photosynthetic parameters of three-year-old P.sibirica L.leaves under different shading conditions with CIRAS-2 portable photosynthesis system.The results showed that：（1） With the aggravation of shading,the net photosynthetic rate（Pn）,light compensation point,light saturation point,dark respiratory rate and growth parameters were declined,and there were significant differences in these photosynthetic parameters.Compared with full day light intensity,the maximum of Pn decreased by 58% and 38% under 70% shading and 40% of shading treatments,while the apparent quantum yield increased by 31% and 22%,respectively.（2）With shading treatment,the diurnal variation of Pn presented a single peak.Under 70% shading and 40% shading treatments,the mean Pn of diurnal variation decreased by 68% and 49%,respectively.With the aggravation of light intensity,the predominant cause of Pn midday depression had turn into non-stomatal limitation.（3）The transpiration rate increased as the aggravation of light intensity.Under 70% shading and 40% shading treatments,the mean transpiration rate of P.sibirica L.decreased by 55% and 16%,respectively.The sequence of mean and maximum water use efficiency of P.sibirica L.was in order of 70% shadingfull day light intensity40% shading,with physiological characteristics of lower transpiration rate and higher water use efficiency in low light.This study suggested that P.sibirica L.had the property of light demander,while it had the ability of shade tolerance in a certain degree,which indicated that P.sibirica L.has wider light ecological amplitude,and it is feasible for shading plantation in semi-arid loess hilly area in order to enhance water use efficiency.
出处
《西北植物学报》
CAS
CSCD
北大核心
2010年第11期2279-2285,共7页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金(30872003)
山东省自然科学基金(Y2008D52)
山东省高校科研发展计划(J09LC64)
滨州学院博士科研基金(2006Y06)
关键词
山杏
遮光
光合特性
净光合速率
水分利用效率
Prunus sibirica L.
shading
photosynthetic characteristics
net photosynthetic rate
water use efficiency
