不同模拟增雨下白刺比叶面积和叶干物质含量的比较

以荒漠生态系统典型植物白刺(Nitraria tangutorum)为研究对象,根据内蒙古磴口多年平均降水量和植物生长规律,设计两个增雨时段(生长季前期与生长季后期),每个增雨时段设置两个增雨梯度(72.5mm/a(50%)、145mm/a(100%)),对天然白刺灌丛进行增雨实验,研究了不同模拟增雨处理下2012年与2013年生长季白刺叶片的比叶面积(SLA)与叶干物质含量(LDMC)的变化。结果表明,增雨处理可以增加白刺叶片的SLA及LDMC,同时期增雨100%处理对SLA及LDMC的影响大于50%处理,但同时期增雨的两个处理之间无显著差异;白刺叶片SLA在生长季前期对水分响应明显,LDMC则在生长季后期对水分反应敏感;相同增雨处理,2012年白刺叶片SLA及LDMC的净增加值高于2013年;SLA与LDMC在2012年呈显著负相关,在2013年虽呈负相关,但相关性不显著。在未来降雨增加的背景下,荒漠植物白刺叶片SLA与LDMC对增雨具有较强的协调适应能力,在不同生长季节可以通过改变不同的叶片性状来适应环境变化。

Specific leaf area and leaf dry matter content of Nitraria tangutorum in the artificially simulated precipitation

Specific leaf area(SLA, leaf area per unit dry mass)and Leaf dry matter content(LDMC, the ratio of leaf dry mass to fresh mass)as important variables in plant ecology, scientists research leaves traits mainly by the SLA and LDMC because they are associated with many critical aspects of plant growth and surviva1in different environment and they are can be simple measured. In this paper, the typical plants Nitraria tangutorum leaves was chosen as research materials, and according to years average precipitation of Dengkou and plant growth regulation, designed the two precipitation enhancement period (May to July, August to September), each precipitation enhancement period set two rain enhancement gradients (72.5mm/ year(50%),145mm/years (100%)), conducted the artificial simulation of precipitation enhancement to natural Nitraria tangutorum shrubs. We examined changes of SLA and LDMC of Nitraria tangutorum leaves during growing season in 2012 and 2013. The results showed that the artificially simulated precipitation (B/C/D/E treatment)added SLA and LDMC of Nitraria tangutorum leaves, at the same simulated precipitation period, effect of SLA and LDMC in 100% treatment was greater than 50% treatment, however, there was no significant difference between tow treatments in the same simulated precipitation period; SLA response to simulated precipitation in the early stage of the growing season was obviously, on the contrary, LDMC was sensitive to simulated precipitation in the late stage of the growing season. The same treatment of two years, the net added(precipitation treatments minus contrast) of SLA and LDMC of leaves in 2012 was greater than 2013;the relationship between SLA and LDMC in 2012 was significantly negatively correlated, but in 2013 it was not significantly correlated although the relationship was negatively correlated. In the context of future in rainfall creased, SLA and LDMC of Nitraria tangutorum leaves had strong ability of adapt and coordination to rainfall increased and it cloud adapted to the environment by changing leaf traits in the different growing seasons.