摘要
吹风会影响到植物的水力学结构、光合作用、生物量分配以及植物的力学性状,研究风对植物的综合影响有助于深入了解植物应对风胁迫的响应机制。以黄花蒿为研究对象,每天吹风4h,风速为5m/s,吹风处理60d,测定了风吹条件下黄花蒿的水力学特征、光合作用、生物量分配和茎干力学特性。结果表明:在风吹条件下,黄花蒿正午水势显著低于对照,茎干导水损失率(PLC)增加了16%,最大光合速率仅为对照的62%,气孔导度为对照的55%。在试验结束时风吹植株株高仅为对照的68%,但基茎显著高于对照,同时风吹显著降低了黄花蒿的总生物量,但根冠比显著高于对照,风吹显著减小了茎导管直径和导管密度,风吹植物导管直径和导管密度分别为对照的77%和55%,同时,风吹植物茎干导水率显著低于对照,但茎干的抗弯刚度显著高于对照。以上结果表明风吹抑制了植物的水分输导能力,导致叶片水分匮缺,限制了植物的光合作用。风吹增加了茎干的力学稳定性,但同时降低了茎干的水分输导能力,这是植物茎在力学性状和水分输导之间的权衡。这种改变有利于在有风条件下维持植物的力学稳定性,但同时降低了水分输导能力。
Wind is one of the most ubiquitous ecological factors affecting hydraulic properties, photosynthesis, mechanical properties and biomass distribution. In spite of more than two centuries of research, the response mechanism of plants to wind remains poorly understood. A major difficulty with understanding the effects of wind is that it affects both water balance by blowing the air and mechanical properties by wind drag. Yet it is uncertain that what patterns wind blowing influences stem hydraulic structure of plants. The relation between stem hydraulic structure and mechanical properties imposed by wind is rarely studied. Thus, study on comprehensive effects of wind on plants can contribute to understanding plant response mechanism under wind stress. In this study, Artemisia annua was used as material to evaluate the impacts of wind on plants. The wind-treated plants were blowed four hours everyday with wind speed of 5m/s for 60 days. We comparatively measured hydraulic properties, photosynthesis, mechanical properties of stem and biomass distribution of A. annua between wind blowing treatment and no wind control. The results showed that wind blowing significantly reduced midday twig water potential, and wind blowing significantly increased stem percent loss in conductivity （PLC）, with PLC being 60.6% and 44.3% for wind blowing treatment and control respectively. The maximum net photosynthetic rate and stomatal conductance of plants subjected to the wind were also reduced, which was only 62% and 55% of the control respectively. The height of A. annua subjected to wind blowing was only 68% of the control at the end of the experiment, while the stem taper of wind blowing treatment was markedly higher than that of control. Total biomass was significantly decreased by the wind, with total biomass being （44.0±6.03） g and （32.8±7.01） g for control and wind blowing treatment respectively, while root/shoot ratio was significantly increased. However, flexural stiffness （EI） of treated plants was considerably higher compared to the control. Meanwhile, wind blowing reduced both stem vessel diameter and vessel density, with stem vessel diameter and vessel density being 77% and 55% as much as that of control respectively. Those results indicated that wind blowing limited the ability of plant hydraulic conductivity, leading to leaf water deficits through increasing cavitation embolism and decreasing the abality of hydraulic conductivity of stem, which limited plant photosynthesis, resulting in the reduction of total biomass. Wind blowing increased the mechanical stability of the stem through increasing thickness of stem and supporting tissue proportion, but decreased the hydraulic conductivity, which was a trade-off between mechanical properties and water transport in stem. These changes were beneficial to maintaining mechanical stability for plants subjected to the wind, but the ability of water transport was lowed at the same time.
出处
《生态学报》
CAS
CSCD
北大核心
2015年第13期4454-4461,共8页
Acta Ecologica Sinica
基金
中央级公益科研院所基本业务专项资金(CAFINT2010K09)
山西农业大学博士启动基金(2013YJ19)
关键词
黄花蒿
生长
水力学结构
力学特性
风
Artemisia annua Linn
growth
hydraulic structure
mechanical properties
wind
作者简介
通讯作者Corresponding author．E—mail：wxc@cal．ac．cn
