塔克拉玛干沙漠南缘3种荒漠植物光合特性的比较  

Comparison of photosynthetic characteristics of three species growing at the southern fringe of the Taklimakan Desert

作　　者：朱军涛[1,2,3] 李向义[1,3] 张希明[1,3] 林丽莎[1,3] 杨尚功[1,3] 

机构地区：[1]中国科学院新疆生态与地理研究所,荒漠与绿洲生态国家重点实验室,新疆乌鲁木齐830011 [2]中国科学院地理科学与资源研究所,陆地水循环及地表过程重点实验室,北京100101 [3]中国科学院策勒荒漠草地生态系统国家野外科学观测研究站,新疆策勒848300

出　　处：《干旱区地理》2012年第1期171-176,共6页Arid Land Geography

基　　金：国家科技支撑项目(2009BAC54B03);新疆科技计划项目(200933125);国家重点基础研究发展计划资助(2009CB421303);国家自然科学基金青年基金(41101056);中国博士后科学基金(20110490571)

摘　　要：在2008年6、7和8月中旬,以塔克拉玛干沙漠南缘固氮植物骆驼刺(Alhagi sparsifoliaShap.)和非固氮植物柽柳(Tamarix ramosissima Ledeb.)、花花柴(Karelinia caspica Less.)为研究对象,研究了两种类型植物的净光合速率、光响应、CO2响应模型参数、叶绿素和叶氮含量等。结果表明:固氮与非固氮植物净光合速率日变化趋势,6月和7月均为双峰曲线,8月为单峰曲线;3个月光合速率平均值花花柴>柽柳>骆驼刺,即非固氮植物具有更高的净光合速率。最大净光合速率(Pmax)、表观量子效率(AQY)、CO2饱和点(CSP)和暗呼吸速率(Rday),非固氮植物>固氮植物,且差异达到显著(P<0.05);羧化效率(Vcmax)和电子传递速率(Jmax),柽柳和骆驼刺差异不显著(P>0.05);光饱和点(LSP)和补偿点(LCP)、CO2补偿点(CCP),固氮植物>非固氮植物,且差异达到显著(P<0.05);叶绿素和叶氮含量,固氮植物>非固氮植物,且差异均达显著水平(P<0.05)。通过双因素相关性分析,骆驼刺的Pmax与Chl、叶氮含量之间无显著的相关性,柽柳和花花柴的Pmax与Chl之间也无显著的相关性,柽柳的Pmax与叶氮含量呈一定的负相关,而花花柴的Pmax与叶氮含量呈一定的正相关。尽管固氮植物叶氮含量较高,但光合速率表现为非固氮植物高于固氮植物,这说明叶片中高的叶氮含量并不一定引起高的光合速率。Indigenous vegetation in the foreland of fiver oases at the extremely arid southern margin of the Taklima- kan Desert in Xinjiang, NW China, is dominated by a few perennial phreatophytes, primarily Alhagi sparsifolia Shap. , Tamarix ramosissima Ledeb. and Karelinia caspica Less. Water is well known as a limiting factor for plant growth in deserts, availability of nutrients has also been determined as a critical factor limiting plant growth in arid regions. Water source for plants is groundwater at the southern fringe of the Taklimakan Desert. So nutrients are the most important resource for plant growth in the same groundwater depth. When the soil N content or the nitrogen validity are low, plants with the ability to fix N2 might have an advantage and be capable of taking in more N than plants without this ability. Leaf N content correlates strongly with photosynthesis as most of the leaf N is allocated to photosynthesis. So some people considered that the nitrogen fixing plants might have higher Pmax than the nitrogen non-fixing ones living in the same habitat. However, in our previous research, we found that nitrogen non-fixing spe- cies had higher photosynthetica capacity. In order to answer this question, nitrogen fixing species A. sparsifolia and nitrogen non-fixing species K. caspica and T. ramosissima were compared in their typical habitat at the southern fringe of the Taklimakan Desert. The diurnal variations of net photosynthetic rate, indexs of light and CO2 to net photosynthetic rate （Pn）, Chl content, leaf nitrogen content of nitrogen fixing and non-fixing species were investiga- ted in June,July and August 2008. The results showed that from 08：00 to 20：00 the diurnal variations of Pn showed double peak curve both nitrogen fixing and non-fixing species in June and July. In August, the curve changed into a single peak. The order of average photosynthetic rate of three months： K. caspica 〉 T. ramosissima 〉 A. sparsifo- lia. It also showed that nitrogen non-fixing species had higher Pn than

关 键 词：光合特性 叶绿素含量 叶氮含量 固氮与非固氮植物 塔克拉玛干沙漠 

分 类 号：Q945.11[生物学—植物学]