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锥连栎林是金沙江干热河谷仅有的几种重要天然植被之一,由于恶劣的气候环境以及长期严重的人为干扰作用,林地生境破碎化程度较高,幼苗天然更新极为困难.分析了锥连栎林更新幼苗主要生长的落叶堆积洼地、落叶堆积平地、菁沟冲积台地和缓坡草丛等4种微生境特点,并比较研究了不同微生境下天然更新幼苗生长的形态特征、生物量分配以及幼苗生存状况.结果表明:1)锥连栎天然更新幼苗生长的4种微生境,在土层厚度、枯落物厚度以及不同季节尤其是旱季时表层土壤水分含量上均存在明显差异,在定居幼苗数目上,落叶堆积洼地>菁沟冲积台地>落叶堆积平地>缓坡草丛.2)不同微生境下天然更新幼苗形态特征的差异主要表现在苗高、主根长度以及比叶面积,地径和叶片数目等差异不显著,其中,生长在落叶堆积洼地上的锥连栎幼苗的苗高、地径、主根长以及叶片数均为4种微生境中最高,而生长在缓坡草丛中的幼苗均为最小.落叶堆积洼地上幼苗的比叶面积最大,缓坡草丛的最小.3)不同微生境下幼苗地上部分、地下部分、根茎比以及植株生物量干重均存在极显著差异,其中,根茎干重比为缓坡草丛>菁沟冲积台地>落叶堆积平地>落叶堆积洼地,而全株干重为落叶堆积洼地>落叶堆积平地>菁沟冲积台地>缓坡草丛.4)不同微生境下幼苗经过旱季以后的生存状况表现出了明显的差异,有69.2%~95.2%的幼苗出现不同程度的死亡、茎干或叶片枯萎现象,其中,菁沟冲积台地上幼苗死亡比例最高,达到了64.3%,缓坡草丛中幼苗死亡比例最低,为23.1%.以上结果表明,落叶堆积洼地和落叶堆积平地是锥连栎林下幼苗定居相对较为理想的微生境;缓坡草丛上虽然幼苗定居较为困难,但一旦定居成功,其成活机率较大;菁沟冲积台地上能够聚积较多种子,从而形成较多幼苗,但由于土层薄,保水性能差,旱季时幼苗容易大量死亡.图2表7参22
Cone-oak forest is one of the few important natural vegetation in Jinshajiang dry-hot valley. Due to the harsh climate and long-term serious human disturbance, the habitat fragmentation is very high, and natural renewal of seedlings is extremely difficult. The results showed that 4 species of micro-habitat, such as deciduous land, deciduous land, deciduous alluvial platform and gentle slope grassland, were the main growth habitats for Q. mongolica, and the morphological characteristics, biomass allocation, and biomass allocation of natural regeneration seedlings under different micro-habitats The results showed that: 1) Four kinds of micro-habitats of natural regeneration seedlings of Quercus acutissima showed obvious differences in soil thickness, litter thickness and surface soil moisture in different seasons, especially in dry season. The number of seedlings, the deciduous depressions depression> Jing ditch alluvial platform> the deciduous land> the gentle slope grass.2) The differences of morphological characteristics of natural regeneration seedlings under different micro-habitats were mainly observed in seedling height, length of main root and specific leaf area, The number of such differences was not significant, which grow in deciduous depressions depression Coniferous oak seedling height, diameter, the main root length and leaf The number of seedlings was the lowest in four kinds of micro-habitats, and the seedlings grew in gentle slope grass was the smallest.The specific leaf area of the seedlings in the depression depression was the largest, , Rhizome ratio and dry weight of plant biomass all had extremely significant differences. Among them, the ratio of dry weight to dry weight was rhizomatous slope> alluvial platform> deciduous land> deciduous depressions, dry weight of whole plant was deciduous depressions> deciduous accumulation The results showed that there were obvious differences in the survival of seedlings under different micro-habitats after the dry season, with 69.2% -95.2% of the seedlings experiencing different degrees of death, withered stems or leaves withered , In which the proportion of seedling death on the alluvial platform was the highest (64.3%) and the lowest on the gentle slope grassland (23.1%). The above results showed that the deciduous land and the deciduous land were planted under the coniferous-oak forest Although the seedlings settle on the gentle slope grassland is more difficult, once the settlement is successful, the probability of survival is larger. The more seed can be accumulated on the alluvial platform of Jinggou, More into seedlings, but thin soil, water retention performance difference when dry mass mortality of the seedlings easily. FIG. 2 reference 22 Table 7