摘要
以青藏高原东北部亚高山生态系统中的两种不同生境优势树种祁连圆柏和青海云杉3a生实生苗为研究对象,研究了它们的幼苗在适宜水分(田间持水量的80%)、轻度干旱(60%)、中度干旱(40%)、重度干旱(20%)生理生态特征差异.结果表明:随着干旱胁迫的加剧,青海云杉和祁连圆柏的叶片相对含水量(RWC)、光合速率(Pn)、气孔导度(Gs)、蒸腾速率(E)逐渐下降,叶片碳稳定同位素含量(δ13 C)、氮素利用效率(NUE)、瞬时水分利用效率(WUEi)、丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性逐渐增加,但根冠比(R∶S)响应不一致,青海云杉响应逐渐降低,而祁连圆柏响应逐渐升高.二者对干旱胁迫的响应有显著差异,青海云杉在所测定的生理生态指标中受干旱胁迫影响更大,说明青海云杉对干旱胁迫更为敏感,而祁连圆柏具有更强的耐旱性.
The differences of ecophysiological features in four levels of field capacity： 80%,60%,40% and 20%,respectively,regarded as well watered,mild,moderate and severe drought stress,were studied using Sabina przewalskii and Picea crassifolia,two dominant species in the subalpine coniferous forest zone in the northeastern Tibetan Plateau,as objects.It is revealed that drought stress significantly decreases the folia relative water content（RWC）,photosynthetic rate（Pn）,stomatal conductance（Gs） and transpiration rate（E）,and increases the foliar carbon stable isotope composition（δ13C）,nitrogen use efficiency（NUE）,instantaneous water use efficiency（WUEi）,content of malonaldehyde（MDA） and activity of superoxide dismutase（SOD） of S.przewalskii and P.crassifolia.Their distribution in biomass（i.e.,root shoot ratio,R∶S） are different,i.e.,the R∶S of P.crassifolia decreases gradually,inversely,the one of S.przewalskii increases gradually.However,there is significant divergence to drought stress response in the two species.The effect of P.crassifolia is larger than that of S.przewalskii,illustrating that P.crassifolia is sensitive to water stress.All results indicate that S.przewalskii possesses more drought tolerance than P.crassifolia.
出处
《冰川冻土》
CSCD
北大核心
2012年第1期147-154,共8页
Journal of Glaciology and Geocryology
基金
冰冻圈科学国家重点实验室开放基金项目(SKLCS 09-01)
中国博士后科学基金(20080430795)
王宽诚教育基金会和教育部新世纪优秀人才支持计划(NCET-08-0257)资助
关键词
祁连圆柏
青海云杉
干旱胁迫
生理生态特征
根冠比
Sabina przewalskii
Picea crassifolia
drought stress
ecophysiological features
root shoot ratio
