摘要
在苗木生长的不同时期对13个毛白杨(Populus tomentosa)杂种无性系叶片碳同位素δ13C和气体交换参数(净光合速率Pn、蒸腾速率Tr、瞬时水分利用效率WUEi、气孔导度Gs和胞间CO2浓度Ci)的差异进行研究,分析不同无性系间δ13C与气体交换参数的相互关系,目的在于探求δ13C在筛选高光合及高水分利用效率毛白杨杂种无性系中的应用价值。结果表明:不同生长时期和不同无性系间δ13C、Tr、WUEi、Gs和Ci的差异均显著,δ13C和WUEi表现为9月>7月,Tr、Gs和Ci表现为7月>9月,Pn在不同生长时期差异不显著。季节变化是引起毛白杨杂种无性系叶片δ13C差异的主要原因。同一时期,无性系间δ13C和WUEi表现出较好的一致性,即WUEi较高的无性系30、42、46、83、BL2和BL5,其δ13C值也较高,WUEi较低的无性系B331和TG34,其δ13C值也较低,且不同时期(7月和9月)δ13C和WUEi呈较强的正相关,相关系数r分别为0.7390和0.5458,高δ13C可以作为筛选高WUEi毛白杨的有效指标,且在苗木生长旺盛时期选育能得到更为可靠的结果。对毛白杨而言,高WUEi的无性系,一般具有适中或较低的Gs和Ci,但不一定具有很高的Pn,气孔调节使得毛白杨在不影响光合作用的同时保持较高的WUE。
Aims Fast, efficient breeding of fast-growth and high water use efficiency (WUE) in Populus tomentosa clones is a pressing need for afforestation in arid and semi-arid regions. There is much research on the correlation between stable carbon isotope and WUE in crops and a few trees, but little in different clones of P. tomentosa. Our objective was to explore the application of δ^13C on selection of clones with high photosynthesis and WUE. Methods We examined 13 clones of Populus-grafted seedlings in Beijing Forestry University (39°46' N, 116°19' E) Nursery in Beijing, China. We studied leaf δ^13C of the seedlings by MAT-251-MS in two different growth periods (mid-July and September) and gas exchange parameters (net photosynthetic rate (Pn), transpiration rate (Tr), instantaneous water use efficiency (WUEi), stomatal conductance (Gs) and intercellular CO2 concentration (Ci)) by LI-6400 portable photosynthesis system between 9:30 and 11:30 a.m. in the same periods. Important findings Leaf δ^13C, Tr, WUEi, Gs and Ci significantly differed between the periods and among clones. Leaf δ^13C and WUEi were higher in July than September; however, Tr, Gs and Ci were lower in July than September and P, showed no significant difference between periods. The main reason for the difference of leaf δ^13C was seasonal variation. Leaf δ^13C and WUEi of the clones were consistent during the same period, i.e, the higher WUEi appeared in clones of 30, 42, 46, 83, BL2 and BL5 with higher δ^13C and the lower WUEi occurred in clones of B331 and TG34 with lower δ^13C. There was strong positive correlation between δ^13C and WUEi (r = 0.739 0 and 0.545 8 in July and September, respectively); therefore, high δ^13C can be used as an effective indicator of high WUEi in Populus. Clones with higher WUEi may have moderate or low G, and C, but not necessarily high Pn.
出处
《植物生态学报》
CAS
CSCD
北大核心
2010年第2期144-150,共7页
Chinese Journal of Plant Ecology
基金
"十一五"国家科技支撑计划课题(2006BAD24B04)
国家自然科学基金(30671675)资助项目