紫斑牡丹(Paeonia rockii)的光合特性及对土壤干旱胁迫的响应

为研究持续干旱处理对紫斑牡丹(Paeonia rockii)光合生理特性的影响,本研究。以实生苗为材料进行盆栽控水试验,设置对照(compared,CK)、轻度胁迫(light stress,LD)、中度胁迫(moderate stress,MD)、重度胁迫(Severe stress,SD)4个水分处理,研究随着干旱胁迫的加剧,叶片水分生理以及光合生理参数的变化。结果表明:在CK、LD、MD水分梯度下,紫斑牡丹生长正常,但在SD胁迫下受影响明显,植株叶片变黄且萎蔫;各胁迫阶段叶厚、叶水势下降明显,相对含水量(relative water content,RWC)降低幅度小,差异不明显,饱和水分亏(water saturation deficit,WSD)有在MD胁迫下有所升高;干旱胁迫抑制了光合色素合成,叶绿素a(Chlorophyll a,Chla)、叶绿素b(Chlorophyll b,Chlb)、叶绿素总含量(total chlorophyll content,Chla+b)、类胡萝卜素(Carotenoids,Car)显著依次下降,叶绿素比值(Chlorophyll ratio,Chla/b)则相反;干旱胁迫导致叶片净光合速率(net photosynthetic rate,Pn)、气孔导度(Stomatal conductance,Gs)以及蒸腾速率(transpiration rate,Tr)呈现下降趋势,但胞间二氧化碳浓度(intercellular carbon dioxide concentration,Ci)则表现为上升后下降,其中水分利用效率(water use efficiency,WUE)在逐渐上升。在轻度和中度干旱的紫斑牡丹表现出一定的适应性和耐旱能力,而长期重度干旱则对紫斑牡丹影响较为严重,在重度干旱地区栽植需考虑水分供给。本研究为干旱地区和城市的园林绿化植物的选择提供理论支持。

Photosynthetic Characteristics of Paeonia rockii and Its Response to Soil Drought Stress

To study the effects of persistent drought on photosynthetic physiological characteristics of P.rockii,pot experiments were conducted with seedlings as materials in this study.Four water treatments,CK,LD,MD and SD,were set up to study the changes of leaf water physiology and photosynthetic physiological parameters with the increase of drought stress.Results is under CK,LD and MD water gradients,the growth of P.rockii was normal,but under SD stress,it was obviously affected,and th e leaves of P.rockii became turn yellow and wilt.Leaf thickness,leaf thickness and leaf water potential decreased significantly,relative water content(RWC)decreased slightly,but the difference was not obvious.Saturated water deficit(WSD)increased under MD stress.Drought stress inhibited the synthesis of photosynthetic pigments,chlorophyll a,chlorophyll b,chlorophyll a+b,carotenoids(Car)decreased significantly in turn,chlorophyll a/b was the opposite.Stomatal closure caused by drought stress affected plant photosynthesis.The net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of leaves decreased under drought stress,but intercellular carbon dioxide concentration(Ci)showed an upward and downward trend,with water use efficiency(WUE)rising gradually.Conclusion is P.rockii spot showed certain adaptability and drought tolerance in mild and moderate drought,while long-term severe drought had a more serious impact on P.rockii spot.Water supply should be considered in planting in severe drought areas.This study provides theoretical support for the selection of landscaping plants in arid areas and cities.