3种卫矛属植物的光合及耗水特性对干旱胁迫的响应

Response of photosynthetic and water consumption characteristics of three Euonymus species to drought stress

近年来干旱频发,严重限制了城市绿化的推进。为了探究卫矛属植物中观赏价值较高的栓翅卫矛和华北卫矛的光合及耗水特性对干旱胁迫的响应,以便为城市绿化植物的选择提供依据,以1年生实生苗的青海种源栓翅卫矛(Q)、河南种源栓翅卫矛(N)和华北卫矛(H)为试验材料,通过人工模拟水分胁迫环境,测定不同卫矛的光合及耗水特性,并通过隶属函数分析法对干旱胁迫进行评价。结果表明:在整个干旱胁迫过程中,Q、N和H的气孔导度(G_(s))、净光合速率(P_(n))、蒸腾速率(T_(r))和胞间CO_(2)浓度(C_(i))均呈降低的趋势,分别降低了80.8%、89.7%、78.9%、27.8%,97.0%、96.2%、95.5%、11.3%和97.9%、92.9%、96.9%、18.9%;在不同梯度的干旱胁迫下,苗木的耗水速率日变化都只呈现一个明显的峰值,但其峰值点却发生了偏移。隶属函数结果表明,在正常水分条件下抗旱能力为H>Q>N,在轻度干旱下为N>Q>H,在重度干旱下为Q>N>H。综合来看,栓翅卫矛是相对高光合低耗水的树种。其中,Q在相同程度干旱胁迫下,其还能保持相对较好的气体交换和吸水能力来维持正常的生理活动。

In recent years,frequent droughts have severely limited the advancement of urban greening.In order to provide a basis for the selection of urban greening plants,the responses of photosynthetic and water consumption char-acteristics of Euonymus phellomanus and Euonymus maackii to drought stress were studied,taken one-year-old seed-lings Qinghai provenance of E.phellomanus(Q),Henan provenance of E.phellomanus(N)and E.maackii(H)as the experimental materials.The photosynthetic and water consumption characteristics of different Euonymus alatus were determined by artificial simulation of water stress environment,and the drought stress was evaluated by membership function analysis.The results showed that the stomatal conductance(G_(s)),net photosynthetic rate(P_(n)),transpiration rate(T_(r))and intercellular CO_(2) concentration(C_(i))of Q,N and H seedlings were decreased by 80.8%,89.7%,78.9%and 27.8%,97.0%,96.2%,95.5%and 11.3%,97.9%,92.9%,96.9%and 18.9%,respectively.Under different gradients of drought stress,the diurnal variation of water consumption rate of seedlings showed only an obvious peak,but the peak point shifted.The results of subordinate function showed that the drought resistance was H>Q>N under normal water condition,N>Q>H under mild drought,and Q>N>H under severe drought.Taken together,E.japonicus is a tree species of relatively high photosynthetic low and water consumption.Under the same degree of drought stress,Q can maintain relatively good gas exchange and water absorption capacity to maintain normal physiological activities.