遮光对牡丹光合及其他生理生化特性的影响

在大田条件下研究不同程度遮光对牡丹光合、荧光日变化及其他生理生化特性的影响。结果表明:在自然光照条件下,10:00—14:00,牡丹Pn出现光合午休现象,Fv/Fm、ΦPSⅡ中午时也会降到日变化的最低值,MDA和O2—.含量和POD活性较高,SOD、叶绿素总量、叶绿素b的相对含量、总酚、类黄酮、谷胱甘肽的含量都较遮光30%条件下低。遮光30%和50%条件下,Pn没有出现光合午休现象,Fv/Fm、ΦPSⅡ在中午时下降都较小,叶绿素总量和叶绿素b的相对含量较高。尤其是遮光30%条件下,平均Pn在一天中保持较高,总酚、类黄酮、谷胱甘肽的含量显著高于其他处理。遮光80%条件下,Pn在一天中始终处于最低水平,SOD,POD的活性和总酚、类黄酮、谷胱甘肽的含量最低,MDA含量最高,综合比较各参数发现,遮光30%最适合牡丹的生长。

Effects of Shading on Photosynthesis,and Other Physiological and Biochemical Characteristics in Tree Peony

This study investigated effects of shading on the photosynthesis,and other physiological and biochemical characteristics of tree peony (luoyanghong).The result showed:Under the natural full sunshine the net photosynthesis (P_n) of tree peony had a midday depression during 10:00-14:00.F_v/F_m and Φ_(PSⅡ) were both decreased to the lowest point at noon.The contents of MDA and O-2 were higher,while the activity of SOD and POD,the content of total chlorophyll,relative content of chlorophyll b,total hydroxybenzene,flavonoid and glutathione were all lower than that under the condition of 30% shading.Under the condition of 30% and 50% shading the phenomenon of "midday depression" did not occur,and the F_v/F_m and Φ_(PSⅡ) both had a smaller decline at noon,the content of total chlorophyll and the relative content of chlorophyll b was both the higher in comparison with the full sunshine condition.P_n maintained a higher level all day under the condition of 30% shading,and the content of total hydroxybenzene,flavonoid and glutathione was all the highest among the four treatments.Under the condition of 80% shading P_n had the lowest level all day,the activity of SOD and POD was both the lowest,the content of total hydroxybenzene,flavonoid and glutathione were also the lowest,and the content of MDA was the highest.It is concluded that tree peony would grow best under the condition of 30% shading in terms of the above comparisons.