短命植物叶片生源要素的化学计量特征及异速关系

摘要

The ephemeral plants formed their own unique ecological stoichiometry characteristics under the extreme habitat conditions.Taking the ephemeral plants in the southern Gurbantunggut Desert as the re-search object,this thesis aims at analyzing the stoichiometric characteristics of leaf biogenic elements of 66 plots,109 plant samples and 42 species in the study area to clarify the stoichiometric characteristics and al-lometric relationships of the main ephemeral plants in the individual scale,population scale and the commu-nity scale,and reveals the main limiting elements which restrict the growth of ephemeral plants in southern Gurbantunggut Desert.The results were as follows:(1 )on the 3 scales,the K content of the ephemeral plant leaves was higher than that of the national average,while the content of P and N was lower than that of the national average level and N∶P mean values were less than 14.The Ca contents of individual scale and population scale is lower than that of the national average,while the Ca content is higher than that of the national average level under community scale.(2)The correlation among the elements of the individual scale is Ca-Mg highest,K-Mg second,and Ca-S minimum,and the growth rate of each element is signifi-cantly deviated from 1,which showed the allometric growth of the various elements and the growth rate of Mg > Ca > K > P > Fe > N > S.(3)The rate of Ca-Mg in the population scale was 0.82 (close to 1), which showed that the two elements are roughly constant growth.The growth rate of each element is Ca>K>P>S>N>Fe.In addition,the Ca was the largest,which indicated that plants could get more Ca to prepare for flowering and reproduction during the period of plant biomass large accumulation.(4)The goodness of fit of each element on the community scale is higher than that of the individual scale and each elements have significant allometric growth realationship.The growth rate is K>Ca>Mg>S>P>N>Fe,which showed that the utilization rate of distinct elements is not same.The result found that the south-ern Gurbantunggut Desert ephemeral plants were restricted by N and P but more susceptible to N limita-tion.It also verified that the species with high consistent biological characteristics and the same ecological adaptability will have higher goodness of fit in the community scale.%短命植物经长期进化形成了独特的生态化学计量特征,该研究以古尔班通古特沙漠南缘主要短命植物为研究对象,通过对研究区的66个样方、109个植物样品、42个物种的叶片生源要素的化学计量特征进行分析,以明确研究区的主要短命植物在个体尺度、种群尺度、群落尺度上的化学计量特征及异速关系,揭示制约古尔班通古特沙漠南缘短命植物生长的主要限制元素。结果显示：(1)在3个尺度上,短命植物叶片 K 含量均高于全国平均水平,而 N、P 含量均低于全国平均水平,且 N∶P 均值都小于14；Ca 含量在个体尺度和种群尺度上低于全国平均水平,而群落尺度上高于全国平均水平。(2)个体尺度上,各生源要素间的相关性以 Ca-Mg 最高、K-Mg 其次、Ca-S 最低；各元素增长斜率显著偏离1,各元素间呈异速增长关系,增长速率为 Mg>Ca>K>P>Fe>N>S。(3)种群尺度上,Ca-Mg 的增长指数为0.82(接近1),说明两元素间大致呈等速增长,各元素间的增长速率为 Ca>K>P>S>N>Fe,其中 Ca 的增长速率最大,它在植物生物量大量积累时期,植物会获得更多的 Ca 为开花繁殖做准备。(4)群落尺度上,各元素间相关性的拟合优度都高于个体尺度,各生源要素间具有显著的异速增长关系,增长速率为 K>Ca>Mg>S>P>N>Fe,表明短命植物对不同元素的利用速率不同。研究发现,古尔班通古特沙漠南缘短命植物在受 N、P 限制的同时更易受 N 限制,群落尺度上具有较高一致性生物学特征和相同生态适应性的物种具有更高的拟合优度。