木麻黄的两种化感物质对其水培幼苗叶绿素荧光参数的影响

Effect of Two Allelochemicals of Casuarina equisetifolia L. on Chlorophyll Fluorescence Parameters in Hydroponically Cultured Seedling

为探明木麻黄对自毒胁迫的抗性机理,进而为解决木麻黄连栽障碍提供实验依据,以同一基因型的‘惠安1号’木麻黄(Casuarina equisetifolia L.)水培幼苗为材料,研究了木麻黄两种化感物质槲皮黄素-3-α-阿拉伯糖苷(化感物质A)和槲皮黄素-3-β-葡萄糖苷(化感物质B)0(CK)、12.5、25、50、100、200、400 mg L-1浓度模拟胁迫对木麻黄幼苗小枝叶绿素荧光特性的影响,并用模糊数学的隶属函数法对幼苗的抗化感胁迫性进行综合评价.结果显示:在轻度(12.5、25、50 mg L-1)胁迫下木麻黄F0、Fm、Fv/F0和Fv/Fm变化不大,Fv/Fm仍保持0.78左右,光合生理正常进行.随着化感物质胁迫浓度的升高(100、200、400 mg L-1),木麻黄幼苗小枝的F0、qN、Drate、LPAR显著升高(P<0.05),Fm、Fv/Fm、Fv/F0、Prate、ΦPSⅡ、qP显著下降(P<0.05),表明化感物质胁迫对木麻黄幼苗小枝PSⅡ反应中心造成了破坏,光电子传递速率降低,热耗散途径受阻,影响了激发能在PSⅠ和PSⅡ的平衡分配,光合机构受损.而不同化感物质胁迫下木麻黄幼苗小枝叶绿素荧光参数随胁迫程度的变幅不同,木麻黄对化感物质A的抗性强于对化感物质B.

In order to investigate the resistance of Casuarina equisetifolia L. to autotoxicity and to provide scientific basis for continuous planting of C. equisetifolia, clones of 慔uian No.1？C. equise？？tifolia were water cultivated to study the effects of chlorophyll fluorescence in branchlet under allelochemical stress （of seven concentrations： 0, 12.5, 25, 50, 100, 200 and 400 mg L-1） induced by quercetin-3-α-araboside （allelochemical A） and quercetin-3-β-glucoside （allelochemical B）, and the membership function of fuzzy mathematics was used to analyze the tolerance abilities of C. equisetifolia seedling under different allelochemicals stress. The results showed slight variations in F0, Fm, Fv/F0 and Fv/Fm of the branchlet under slight allelochemicals stress （12.5, 25, 50 mg L-1）. The Fv/Fm was observed to maintain 78% of normal photosynthesis reaction. The F0, qN, Drate, LPAR of the branchlet significantly （P 〈 0.05） increased with the concentration of allelochemicals（100, 200, 400 mg L-1）, while the values of Fm, Fv/Fm, Fv/F0, Prate, ΦPSⅡ, qP decreased significantly （P 〈 0.05）. Allelochemicals stress damaged the function of PSⅡ reaction center and decreased the photochemical electron transfer rate which led to the structural damage of photosynthetic organs and functional degradation in photosynthetic ability. The range of chlorophyll fluorescence parameters in branchlet of C. equisetifolia varied with different allelochemicals,the seedlings had better stress tolerance against allelochemical A than allelochemical B. Fig 3, Tab 1, Ref 28