冰雪灾害后木荷倒木萌枝光合特性研究

Photosynthetic characteristics of resprouts on uprooted Schima superba after great ice storm

关键词:  萌枝  日变化  光合效率  环境因子  冰雪灾害

Key words:  resprouts  diurnal variation  photosynthetic rate  enviromental factors  ice storm

摘要:

采用Li 6400型便携式光合测定仪，对冰雪灾害后夏季木荷倒木萌枝和未受损木荷枝条的叶片进行光合特性研究。结果表明：倒木萌枝和未受损木荷枝条的Pn、Tr和Gs日变化均呈双峰曲线，具有典型的光合“午休”现象，中午Pn降低均为气孔限制；未受损木荷Pn中午午休时间(10：00～15：00)长于倒木的午休时间(11：00～15：00)，其自我保护能力强于倒木，且对光适应的生态辐较宽；环境因子对Pn的直接作用由大到小为倒木：PAR＞Ca＞Ta＞RH，未受损木荷：Ta＞PAR＞Ca＞RH。倒木和未受损木荷的RH与Pn分别呈极显著(P＜001)和显著(P＜0.05)负相关，高温高湿、高湿分别是制约倒木、未受损木荷Pn进一步升高的主要环境因子。

Abstract:

The photosynthetic characteristics of uprooted and undamaged trees on Schima superba were measured in summer by Li 6400 portable photosynthesis system，and the data were analyzed to explore the diurnal variation of photosynthesis and its relationship with environmental factors. The results indicated that the diurnal variation of Pn，Tr and Gs showed a typical double peak curve with a midday depression of photosythesis，and the Pn reduction at noon originated from the co effects of stomata factor. The time of valley for undamaged trees(10：00-15：00)was longer than that of uprooted trees(11：00-15：00). The capacity ability of self protection and the ecological amplitude to light adaptation for uadamaged trees were higher and broader than those of uprooted trees. The direct impact of enviromental factors to Pn was the order of PAR＞Ca＞Ta＞RH for uprooted trees，Ta＞PAR＞Ca＞RH for undamaged trees. There was a significant negative relationship between RH and Pn on uprooted trees(P＜0.01)and undamaged trees(P＜0.05). High temperature and humidity were the most sensitive environmental factor effecting on the Pn of the uprooted trees. High humidity was the most important environmental factor influencing the Pn of the undamaged trees.