干旱胁迫环境中黄栌幼苗叶功能性状变异与产地地理−气候因子的关系

李金航; 朱济友; Catherine MhaeB. Jandug; 赵凯; 徐程扬

doi:10.12171/j.1000-1522.20190079

干旱胁迫环境中黄栌幼苗叶功能性状变异与产地地理−气候因子的关系

Relationship between leaf functional trait variation of Cotinus coggygria seedling and location geographical-climatic factors under drought stress

摘要

摘要:
目的分析持续干旱胁迫环境中不同产地黄栌幼苗叶功能性状的变异规律及差异，并探究产地地理−气候因子对叶功能性状变异的影响。
方法采用田间模拟试验方法，选取来自5个产地的黄栌1年生幼苗作为供试材料，设置对照（CK，土壤田间持水量的75% ~ 80%）、中度胁迫（MS，土壤田间持水量的55% ~ 65%）和重度胁迫（SS，土壤田间持水量的35% ~ 45%）3个土壤水分含量梯度，分析干旱胁迫、产地及其二者的交互作用对叶功能性状的影响，并结合主成分分析（PCA）和冗余分析（RDA）分别研究产地分布与地理−气候因子的关系以及产地地理−气候因子对叶功能性状变异程度（TVD）的影响。
结果（1）干旱胁迫对幼苗叶功能性状均具有显著影响。其中，SS环境中，叶绿素含量（LChl）、叶相对含水量（RWC）、比叶面积（SLA）和叶片面积比例（LAR）分别比对照低17.61%（P < 0.001）、3.71%（P < 0.001）、10.89%（P = 0.002）和17.22%（P = 0.001），叶干物质含量（LDMC）、叶组织密度（LD）分别比对照高9.04%（P < 0.001）和14.52%（P = 0.009）。（2）黄栌叶功能性状之间的相关性在干旱胁迫环境中具有增强的趋势。其中，SLA与LDMC和LD均呈极显著（P < 0.01）的负相关关系，LDMC和LD之间具有极显著（P < 0.01）的正相关关系，RWC与LChl（P < 0.01）、SLA（P < 0.01）和LAR（P < 0.05）呈极显著或显著的正相关关系。（3）干旱胁迫环境中不同产地叶功能性状具有显著差异。MS处理时，SLA（P = 0.002）、LChl（P = 0.025）和LD（P = 0.026）在产地间具有显著差异；SS处理时，LChl（P < 0.001）、LAR（P < 0.001）和RWC（P = 0.005）存在显著的产地差异。（4）来自北京延庆区幼苗的叶功能性状平均变异程度（所有性状变异程度的平均值）最大，为17.57%，而来自山西运城绛县幼苗的最小，为6.97%。（5）经RDA筛选，最干燥月份降水量（DMP，P = 0.002）、生长季月降水量平均差（GSPD，P = 0.008）、最热月份的最高气温（WMT，P = 0.016）和年平均降水量（ANP，P = 0.036）对幼苗TVD影响显著。其中，DMP与所有性状的变异程度之间均具有不同程度的负相关关系，但与LDMC和LD变异程度之间的负相关性更为显著，GSPD和ANP与SLA和LAR变异程度的负相关性较为显著，WMT与LChl变异程度的正相关性极为密切。
结论黄栌叶功能性状在不同干旱胁迫环境中、不同产地间均具有显著差异。产地气候（尤其是DMP、GSPD、WMT和ANP）是导致干旱逆境中不同产地黄栌叶功能性状发生遗传变异的重要原因。5产地中，山西运城绛县的DMP最高，GSPD和ANP较为适宜，WMT较低，且来自该产地的黄栌叶功能性状在干旱胁迫中的平均变异程度最小，因此较适合引种至华北地区的干旱区域。

Abstract:
ObjectiveThis study aims to identify leaf functional trait variation patterns and differences of Cotinus coggygria seedlings from different locations and to analyse the influences of different geographic-climatic factors on leaf functional trait variations under continuous drought environment.
MethodA standard continuous drought stress experiment was carried out using one-year-old C. coggygria seedlings from five different locations within China. Three levels of water regimes were set: control (CK, 75% ~ 80% of soil field capacity), moderate stress (MS, 55% ~ 65% of soil field capacity) and severe stress (SS, 35% ~ 45% of soil field capacity). ANOVA was used to identify the effects of drought, location and their interaction on leaf functional traits. On the other hand, the principal component analysis (PCA) and the redundancy analysis (RDA) were used to measure the relationship between location distribution of the species and the geographical-climatic factors and the influences of geographical-climatic conditions on leaf functional trait variation degree (TVD), respectively.
Result(1) Drought stress had significant effects on all the leaf functional traits. Seedlings under SS had lower leaf function traits in terms of leaf chlorophyll content (LChl, 17.61%, P < 0.001), relative water content (RWC, 3.71%, P < 0.001), specific leaf area (SLA, 10.89%, P = 0.002), and leaf area ratio (LAR, 17.22%, P = 0.001) compared to the seedlings under CK. However, seedlings under SS had higher leaf dry matter content (LDMC) and leaf density (LD) than control by 9.04% (P < 0.001) and 14.52% (P = 0.009), respectively. (2) Correlations among leaf functional traits became stronger in drought environment, which showed that SLA had significantly (P < 0.01) negative links with LDMC and LD, LDMC and LD had a significant (P < 0.01) and positive relation, and RWC had significantly positive correlations with LChl (P < 0.01), SLA (P < 0.01) and LAR (P < 0.05). (3) The leaf functional traits showed significant differences among C. coggygria locations under drought treatments. SLA (P = 0.002), LChl (P = 0.025) and LD (P = 0.026) were significantly different under MS treatment, and LChl (P < 0.001), LAR (P < 0.001) and RWC (P = 0.005) were significantly different under SS treatment. (4) Among the five different locations, C. coggygria seedlings from Yanqing County in Beijing had the highest average trait variation degree (the mean values of all trait variation degrees) of 17.57%, while the lowest was from Jiang County of Yuncheng City in Shanxi Province of 6.97%. (5) After the screening of RDA, precipitation of the driest month (DMP, P = 0.002), growing season mean monthly precipitation difference (GSPD, P = 0.008), Max. temperature of the warmest month (WMT, P = 0.016) and average annual precipitation (ANP, P = 0.036) had significant effects on leaf functional trait variation degree. Particularly, DMP had negative relationships with all trait variation degree, but had more significantly negative correlations with the variation degree of LDMC and LD. GSPD and ANP had significantly negative correlationss with the variation degree of SLA and LAR. WMT was closer to the variation degree of LChl.
ConclusionSignificant differences were found for leaf functional traits of C. coggygria among different drought treatments and different locations. The local climate (especially DMP, GSPD, WMT and ANP) was the main cause of leaf functional trait variation of C. coggygria from different locations under drought stress. Among seedlings from the five locations explored in our study, seedlings from Jiang County of Yuncheng City in Shanxi Province were more suitable to be introduced to the arid areas in northern China, as a result of a relatively high DMP, a proper GSPD and ANP, a relatively low WMT, and a low average leaf functional trait variation degree under drought stress.

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