内蒙古羊草草原植物种能量含量及其在群落中的作用

根据11a的野外实验对内蒙古羊草草原群落42种植物的能量含量（含灰分）及其在群落中的相对生物量进行了研究。不同植物种地上部分的能量含量在（13156±1141）J／g和（18141±527）J／g之间变动，所有物种的平均能量含量为（16899±840）J／g，种间变异系数4．9％。小叶锦鸡儿具有最高的能量含量。禾草的平均能量含量高于杂草。根据生活型和生长型，草本物种被进一步分组，能量含量从高到低的排列顺序为：高禾草（17717±92）J／g〉豆科植物（17228±433）J／g〉矮禾草（17250±218）J／g〉其余杂草（16784±529）J／g〉半灌木（16719±69）J／g〉1、2年生植物（15911±1759）J／g。42种植物的能量含量和它们在群落中的相对生物量存在显著正相关关系。根据它们在群落中的构成比例进行分组，以物种在群落中的相对生物量为权重，各组能量含量依次为：优势种（17740J／g）〉伴生种（17244J／g。）〉偶见种（16653J／g）。高能量含量的植物更具竞争力，在群落中通常占据优势地位，而低能量含量的植物竞争力通常较弱，构成草原群落的伴生种或偶见种。

The caloric content of plant species and its role in a Leymus chinensis steppe community of Inner Mongolia, China

The caloric contents of 42 species and their composition in a Leymus chinensis steppe community of Inner Mongolia in China were determined and analyzed for 11 years. The caloric content (x±1SD) of aboveground parts for plant species varied from (13156±1141) J/g ash-contained to (18141±527) J/g. The average caloric content of all species was (16899±840) J/g and their inter-specific CV was 4.9%. Of all the species, Caragana microphylla had the highest caloric content (18142 J/g). Grasses had a higher (P < 0.05) average caloric content (17425±291)J/g than forbs (16734±844) J/g. When the herbaceous species were classified into subgroups according to life form and growth form, the order of average caloric contents, from high to low, were: tall grasses (17717±92) J/g>Legume (17228±433) J/g>short grasses (17250±218) J/g>remaining forbs (16784±529) J/g>subshrubs (16719±69) J/g>annuals and biennials (15911±1759) J/g. There was a positive correlation (P < 0.05) between the caloric contents of 42 species and their relative biomass in the community. When all species were classified into three groups according to their composition in the community, the averaged caloric contents, weighted by the species relative biomass, followed the order: Dominant (17740 J/g)>companion (17244 J/g)>incidental (16653 J/g). The plants with high caloric contents were more competitive, which allows them to gain a dominant status, while the competitive abilities of plants with low caloric contents were generally weak. The latter made up the companion or incidental species in a steppe community.