作 者 ：曹昀,王国祥
期 刊 ：生态学报 2007年 27卷 5期 页码：1748~1755
Keywords:soil water content, Sweet Flag, germination, seedlings growth, chlorophyll fluorescence,
摘 要 ：应用盆栽试验方法,采用完全随机试验设计,研究了菖蒲在不同土壤水分含量下的萌发和幼苗生长。试验共设6个处理,处理时间为60d。结果表明: （1）水分亏缺对菖蒲萌发和幼苗有不同程度的影响，在持续干旱60d条件下，菖蒲幼苗的萌发率仅为32.5％，为正常水分条件下的1/3，幼苗的平均高度为19.0cm，是正常水分条件下的1/3左右；（2）菖蒲幼苗叶片长度、宽度和基茎随土壤水分含量降低而减小，叶片数量与叶片面积也随土壤水分含量降低而减小，叶片含水率各试验组无明显差异；（3）在试验的20、40、60d，各试验组的根、茎、叶及总生物量都比对照组（CK）有不同程度的降低，并随试验时间的延长，各水分含量条件下的生物量差别增大，在不同土壤水分条件下,根、茎和叶生物量增量均表现为茎的最多, 叶的次之, 根的最少，叶、茎、根生物量比例平均为1∶1.59∶0.82；（4）菖蒲幼苗叶片的叶绿素a、b随土壤水分含量减少而下降，叶绿素a/b随土壤水分含量减少而下降而升高，类胡萝卜素（Car）含量随土壤水分含量减少而下降；（5）Fv/Fm、qP随土壤水分含量降低而下降，重度干旱对菖蒲幼苗光合系统PSⅡ的最大量子产量影响显著，菖蒲幼苗在重度干旱条件下30、45、60d的Fv/Fm分别为0.800、0.796、0.787，分别比对照降低5.0％、4.7％和6.2％；菖蒲幼苗在重度干旱条件下30、45、60d的qN分别为0.270、0.259和0.200，分别是对照的6.75、3.92、2.78倍，可见干旱条件会导致菖蒲幼苗以热的形式耗散掉的光能部分增加，有效保护了菖蒲叶片PSⅡ系统,但持续干旱（60d）导致qN降低，菖蒲叶片PSⅡ系统受到不同程度的破坏；干旱胁迫还对菖蒲植株的光响应曲线具有较大的影响，使最大ETR降低。
Abstract:Soil water content is a crucial factor for the growth of wetland plants. Its influence on germination and seedling growth of sweet flag (Acorus calamus) were studied by pot culture experiment and complete random design. The rhizomes with buds were cultured in small plastic basins. The soil thickness was 25 cm in each small plastic basin. Six soil samples with water content of 10%, 20%, 30%, 35%, 40% and 55%, respectively, were established and their water contents were maintained during the whole 60 days′ experimental period. Germination ratio, growth parameters of leaves and stems, pigment of leaves, photosynthetic fluorescence parameters of sweet flag were measured. The experimental results indicated: (1) Water content had significant effects on germination and seedlings growth of Sweet Flag. Germination ratio and average seedlings height under continuous drought condition were just one thirds of that under normal growth condition; (2) seedling height, leaf width, rhizome diameter, leaf number and leaf area reduced with the decreasing soil water content, but no obvious difference of leaf water content was observed; (3) In comparison with CK, the biomass of root, rhizome and leaf and total biomass of every treatment reduced to different extent on the 20th, 40th and 60th day. With the increase of time, the biomass differences among the soils with different water contents were increased. Ratio of biomass among leaf, rhizome and root was 1: 1.59: 0.82 on average, indicating that biomass increase of rhizome is the largest, while that of root is the least.; (4) Chl a, chl b and carotenoid of seedlings leaf reduced, but chlorophyll a/chlorophyll b ratio increased with decrease of soil water content; (5) Fv/Fm and qP decreased with the increase of soil water content. Severe drought had obvious effects not only on Fm, but also on qN which decreased to different extent on day 45 and 60, indicating that the photosystem apparatus——PSⅡ was destroyed to different degree. Dramatic effects of drought stress on light curve of Sweet Flag were also observed, thus leading to the decrease of maximum ETR.