三江平原小叶章钾、钙、镁含量与累积的季节变化

2004年5—10月，对三江平原典型小叶章草甸和小叶章-苔草沼泽化草甸群落优势植物小叶章的K、Ca、Mg含量与累积的季节变化进行了研究.结果表明：典型草甸和沼泽化草甸小叶章不同器官K、Ca、Mg含量差异较大，其中，其地上器官的K含量整体均呈下降趋势，符合线性模型(y=A+Bt);茎中Ca含量变幅不大，符合抛物线模型(y=A＋B₁t＋B₂t₂)，叶和叶鞘中整体呈递增变化，符合指数增长模型(y=Aexp(t/B₁)+B₂);茎中Mg含量变幅最大，而叶和叶鞘相对平缓.不同时期小叶章各器官K、Ca、Mg含量差异较大，典型草甸小叶章地上器官的K含量大多高于沼泽化草甸小叶章，而沼泽化草甸小叶章根、叶鞘的Ca、Mg含量则高于典型草甸小叶章;典型草甸和沼泽化草甸小叶章不同器官K、Ca、Mg储量及累积速率差异明显，其中根的储量最大，分别占总储量的（63.82±23.19）％、（78.68±15.44）％、（76.48±19.06）％和（85.23±9.20）％、（93.51±3.46）％、（92.39±3.22）％.典型草甸小叶章地上器官K、Ca、Mg储量均明显高于沼泽化草甸小叶章，根则相反.这种差异主要与小叶章生态学特性及所处生境有关。

Seasonal changes of potassium, calcium and magnesium contents and accumulation in Calamagrostis angustifolia in Sanjiang Plain.

From May to October 2004, the seasonal changes of K, Ca, and Mg contents and accumulation in Calamagrostis angustifolia, the dominant species in the typical meadow and marsh meadow communities of Sanjiang Plain, were studied. There was a greater difference in the seasonal changes of K, Ca, and Mg contents in different parts of typical meadow C. angustifolia (TMC) and marsh meadow C. angustifolia (MMC). The K content in aboveground parts of the two communities had an overall decreasing trend, according with linear model K=A+Bt, the Ca content had a smaller change in stem but an overall increasing trend in leaf and vagina, being accorded with parabola model Ca=A＋B1t＋B2t2 and exponential growth model Ca=Aexp(t/B1)+B2, respectively, while the Mg content had the greatest change in stem but changed relatively smoothly in leaf and vagina. The differences of K, Ca, and Mg contents in different parts of TMC and MMC were obvious. The K content in aboveground parts of TMC was generally higher than that of MMC, while the Ca and Mg contents in the root and vagina of MMC were higher than those of TMC. The K, Ca, and Mg storage and accumulation in different parts of TMC and MMC also differed. Root had the greatest K, Ca, and Mg storage, occupying 6382±2319%, 7868±15.44%, and 7648±1906% of the total storage in TMC and 8523±920%, 9351±346%, and 9239±322% in MMC, respectively. The aboveground parts of TMC had a higher storage of K, Ca and Mg than those of MMC, while the root was in adverse. Such a difference was mainly due to ecological characteristics of C. angustifolia and its habitat conditions.