水分胁迫下大丽花光合及叶绿素荧光的日变化特性  

Daily Variation Characteristics of Photosynthesis and Chlorophyll Fluorescence in Dahlia Leaves under Water Stress

作　　者：范苏鲁[1,2] 苑兆和[1] 冯立娟[1] 王晓慧[1,2] 丁雪梅[1,2] 甄红丽[1,2] 

机构地区：[1]山东省果树研究所,山东泰安271000 [2]山东农业大学林学院,山东泰安271018

出　　处：《西北植物学报》2011年第6期1223-1228,共6页Acta Botanica Boreali-Occidentalia Sinica

基　　金：山东省农业良种产业化开发项目(2010-6)

摘　　要：以大丽花品种‘粉西施’为试验材料,采用盆栽方法,研究了不同土壤含水量处理对‘粉西施’叶片光合及荧光特性日变化的影响。结果表明:随着水分胁迫程度的加深,大丽花叶片的Pn、Tr和Gs日平均值均降低,Ci日平均值在轻度和中度胁迫下降低,在重度胁迫下升高;在轻度和中度水分胁迫下大丽花Pn降低的主要原因是气孔限制,而重度水分胁迫下是非气孔因素;Pn在水分胁迫下的日变化曲线由单峰型变成双峰型,出现"午休"现象,且Tr和Gs在水分胁迫下的日变化曲线和Pn一致,但Ci日变化较平稳,与Pn相反。随着水分胁迫程度的加深,大丽花叶片的初始荧光(F0)日平均值升高,日变化曲线呈倒"V"型,PSⅡ反应中心可能破坏或可逆失活;Fm、Fv/Fm和ΦPSⅡ日平均值均降低,日变化曲线呈"V"型。水分胁迫使大丽花光抑制程度加深,抑制了PSⅡ的光化学活性,致使用于光化学反应的光能及实际光化学效率降低。研究结果发现,大丽花品种‘粉西施’在不同水分胁迫下都产生了光合作用的光抑制而使净光合速率降低;光合机构可适应轻度和中度水分胁迫而发生可逆失活,没有受到不可恢复的伤害,而重度水分胁迫降低了叶片的光合机构活性,加剧了光抑制程度,严重限制了光合作用;适宜大丽花生长的土壤含水量应为田间最大持水量的30%以上。The effects of different levels of water stress on daily variation of photosynthesis and chlorophyll fluorescence characteristics of ＇Fenxishi＇ plant were studied by pot experiments.With the increasing extent of drought stress,the daily means of Pn,Tr and Gs of Dahlia decreased;the daily means of Ci increased under light and moderate stress while decreased under severe stress.The main reason of the reduction of Pn in Dahlia leaves was stomatal limitation under light and moderate stress while the main reason was nonstomatal factors under severe stress.The daily curve of the net photosynthesis rate changed from single zenith to double zenith with the influence of water stress,appeared ＂nap＂ phenomenon.Daily variation curve of Tr and Gs under water stress were the consistent with Pn.Contrary to Pn,daily variation of Ci was smooth.With the increasing extent of drought stress,the daily means of F0 in Dahlia increased and its daily changed curve appeared ＂V＂ type.Response center in PSⅡcould be damaged or had reversible inactivation;the daily means of Fm,Fv/Fm and ΦPSⅡ decreased and the daily changed curves appeared ＂V＂ type.Water stress deepened the degree of photoinhibition,curbed the photochemical activity in PSⅡ and reduced the light part used in photochemical reactions and actual photochemical efficiency.The results of study showed that photosynthesis occured photoinhibition in Dahlia＇Fenxishi＇under different levels of water stress,making the net photosynthetic rate reduced.Photosynthetic institutions in Dahlia might have reversible deactivation to adapt to light and moderate stress,not suffered irreversible damage.The activity of photosynthetic institutions decreased by the severe water stress which also increased the severity of photoinhibition and limited the normal process of photosynthesis.So the appropriate relative water content in soil for Dahlia was more than 30% of maximal water content in field.

关 键 词：大丽花 水分胁迫 光合作用 叶绿素荧光 

分 类 号：Q945.78[生物学—植物学]