不同遮光处理对川西柳叶菜部分形态、生长和生理指标的影响

以自然光照为对照,对轻度、中度和重度遮光条件下(遮光率分别为24%、48%和72%)川西柳叶菜( Epilobium fangii C. J. Chen et al.)的部分形态、生长和生理指标进行比较分析。分析结果显示：遮光处理对川西柳叶菜的MDA含量无显著影响,对叶长、花冠宽、叶干质量分配比例以及叶绿素a( Chla)、叶绿素b( Chlb)和类胡萝卜素(Car)含量及Chla/Chlb值有显著影响(P<0.05),对其余指标有极显著影响(P<0.01)。与对照相比,3个遮光处理组的单株根数、株高、主茎长和基径总体上显著下降,根长在轻度和中度遮光条件下略升高、在重度遮光条件下显著升高；3个遮光处理组的单株叶片数和叶长总体上显著下降,叶宽在轻度和中度遮光条件下略下降、在重度遮光条件下显著升高,叶厚在轻度遮光条件下显著升高、在中度遮光条件下略下降、在重度遮光条件下显著下降；3个遮光处理组的花柄长、花管长和花冠高显著升高,单株开花数在轻度遮光条件下略下降、在中度遮光条件下显著升高、在重度遮光条件下显著下降,花冠宽在轻度和中度遮光条件下略升高、在重度遮光条件下显著升高。与对照相比,3个遮光处理组的全株干质量和茎干质量分配比例均显著下降；根干质量分配比例和根冠比在轻度遮光条件下显著升高、在中度和重度遮光条件下略下降；地上部干质量分配比例在轻度遮光条件下显著下降、在中度和重度遮光条件下略升高；叶干质量分配比例在轻度和中度遮光条件下略下降、在重度遮光条件下略升高。在轻度和中度遮光条件下,叶片的Chla、Chlb和Car含量基本上显著高于对照,Chla/Chlb值分别略低于或显著低于对照；而在重度遮光条件下这4个指标均略高于对照。与对照相比,轻度和中度遮光条件下叶片的H2 O2含量和SOD活性略升高,MDA含量和总抗氧化能力略下降；总酚含量在轻度遮光条件下略下降、在中度遮光条件下略升高；重度遮光条件下这5个指标均显著升高。随着遮光程度的增强,川西柳叶菜的单株根数、株高、主茎长、基径和叶厚逐渐下降,而叶宽、全株干质量、叶干质量分配比例、H2 O2含量、SOD活性和总酚含量逐渐升高；其中,在中度遮光条件下,其单株开花数、花柄长、花管长、花冠高、花冠宽和花干质量分配比例最高。结果表明：在遮光条件下,川西柳叶菜可在形态、生长和生理上调整生长策略,完成发育过程；并且,中度遮光有利于其生殖分配,提高其观赏价值。

Effects of different shading treatments on some morphological,growth and physiological indexes of Epilobium fangii

Taking natural light as the control, some morphological, growth and physiological indexes of Epilobium fangii C. J. Chen et al. were compared and analyzed under mild, moderate and severe shading conditions with shading rate of 24%, 48% and 72%, respectively. Analysis results show that shading treatments have no significant effect on MDA content of E. fangii, have significant effect ( P<0. 05) on leaf length, corolla width, allocation proportion of leaf dry weight, contents of chlorophyll a( Chla) , chlorophyll b ( Chlb ) and carotenoid ( Car ) , and Chla/Chlb value, and have extremely significantly effect (P<0. 01) on other indexes. Compared with the control, root number per plant, plant height, main stem length and basal diameter in three shading treatment groups decrease significantly in general, root length increases slightly under mild and moderate shading conditions and increases significantly under severe shading condition; leaf number per plant and leaf length in three shading treatment groups decrease significantly in general, leaf width decreases slightly under mild and moderate shading conditions and increases significantly under severe shading condition, leaf thickness increases significantly under mild shading condition, decreases slightly under moderate shading condition and decreases significantly under severe shading condition;flower stalk length, flower tube length and corolla height in three shading treatment groups increase significantly, flower number per plant decreases slightly under mild shading condition, increases significantly under moderate shading condition and decreases significantly under severe shading condition, corolla width increases slightly under mild and moderate shading conditions and increases significantly under severe shading condition. Compared with the control, dry weight of whole plant and allocation proportion of stem dry weight in three shading treatment groups decrease significantly;allocation proportion of root dry weight and root/shoot ratio increase significantly under mild shading condition and decrease slightly under moderate and severe shading conditions;allocation proportion of above-ground part dry weight decreases significantly under mild shading condition and increases slightly under moderate and severe shading conditions; allocation proportion of leaf dry weight decreases slightly under mild and moderate shading conditions and increases slightly under severe shading condition. Contents of Chla, Chlb and Car in leaf under mild and moderate shading conditions are significantly higher than those of the control in general, Chla/Chlb value is slightly or significantly lower than that of the control, respectively, but these four indexes under severe shading condition are slightly higher than those of the control. Compared with the control, under mild and moderate shading conditions, H2 O2 content and SOD activity in leaf increase slightly, MDA content and total antioxidant capacity decrease slightly; total phenolic content under mild shading condition decreases slightly and increases slightly under moderate shading condition;these five indexes increase significantly under severe shading condition. With enhancing of shading degree, root number per plant, plant height, main stem length, basal diameter and leaf thickness of E. fangii decrease gradually, while leaf width, dry weight of whole plant, allocation proportion of leaf dry weight, H2 O2 content, SOD activity and total phenolic content increase gradually. In which, under moderate shading condition, flower number per plant, flower stalk length, flower tube length, corolla height, corolla width and allocation proportion of flower dry weight of E. fangii are the highest. It is suggested that under shading condition, E. fangii can adjust growth strategy on morphology, growth and physiology, and finish development process; in addition, moderate shading is beneficial to its reproductive allocation and enhance its ornamental value.