中温型和暖温型草原共有植物种群繁殖分配的比较研究

A COMPARATIVE STUDY ON REPRODUCTIVE ALLOCATION OF MUTUAL SPECIES IN MODERATE-TEMPERATE AND WARM-TEMPERATE STEPPE

1999～ 2 0 0 0年在内蒙古草原区的中温型草原和暖温型草原两个研究站点 ,分别对大针茅 (Stipagrandis)、羊草 (Leymuschinensis)、糙隐子草 (Cleistogenessquarrosa)、达乌里胡枝子 (Lespedezadahurica)和阿尔泰狗哇花 (Het eropappusaltaicus) 5个共有种地上生物量、营养元素 (全C、全N、全P)和能量 (热值 )的繁殖分配进行了初步研究。结果表明 :两站点共有种各自的地上生物量、全C和能量之间的繁殖分配较为接近 ,但全P、全N的繁殖分配明显偏高 ,反映出繁殖器官中N ,P元素富集的特征。同时 ,除羊草外 ,暖温型草原各共有种地上生物量、营养元素和能量(热值 )的繁殖分配比例均显著高于中温型草原。研究结果从一个侧面反映出暖温型草原各共有种以较高的繁殖分配比例来适应降水量的年度剧烈波动和极不平衡的季节分布 ;而中温型草原各共有种则通过较高的同化器官比例来适应生长季短促所带来的不利影响。

A comparative study of the reproductive allocation of above ground biomass, nutrient elements (total C, total N, total P) and energy (calorific value) in mutual species such as Stipa grandis, Leymus chinensis, Cleistogenes squarrosa, Lespedeza dahurica and Heteropappus altaicus was carried out in the last stage growth seasons during 1999-2000, using two stations of Warm_temperate Steppe and Moderate_temperate Steppe in the Inner Mongolia Steppe Region. Results demonstrate that the reproductive allocation of biomass, nutrient elements (total C) and energy (caloric value) of these species in the two stations is close, but the reproductive allocation of total N and total P is remarkably higher, reflecting the characteristic concentration of the elements N and P in the reproductive organs. Meanwhile, the reproductive allocation proportion of the biomass, the elements and energy of these species are larger in Warm_temperate Steppe than in Moderate_temperate Steppe, except in Leymus chinensis. The findings show one aspect of adaptation to circumstances of extreme fluctuation among different years and extremely uneven well_distribution of precipitation during the growth seasons by the higher reproductive allocation of these species in Warm_temperate Steppe; and reflect that these species adapt themselves to a shorter growth season and unfavourable effects by increasing the allocation proportion of assimilation organs in Moderate_temperate Steppe.