The present study was conducted in the alpine pastures of Tungnath （30° 14＇ N and 79° 13＇ E） to observe life-form and growth-form patterns of alpine plant species under grazed and ungrazed conditions and...The present study was conducted in the alpine pastures of Tungnath （30° 14＇ N and 79° 13＇ E） to observe life-form and growth-form patterns of alpine plant species under grazed and ungrazed conditions and to work out the plant life form spectrum. Species were categorized as plant habit, height and length of growth-cycle and life-form classes according to Raunkiaer＇s system. The results show that in total of 68 species at grazed site, hemicryptophytes （He） accounted for 50.00% species, followed by cryptophytes （26.47%）, chamaephytes （16.18%）, phanemphytes （4.41%） and therophytes （2.94%）. At the ungrazed site in 65 plant species, hemicryptophytes （He） accounted fo＇r 49.23% species, cryptophytes （26.15%）, chamaephytes （15.38%）, phanerophytes （6.15%） and ther6phytes （3.08 % species）. In general, hemicrptophyte are dominant^in both sites i.e. graged and ungrazed. Growth form categories were classified as forbs, shrubs, grasses and sedges＇and undershrubs, according to plant habit and height. On the basis of length of the growth cycle, species were categorized as plant species of short growth cycle, intermediate growth cycle and long growth cycle. The short forbs of plant habit and height, had the highest emergence, and grasses and sedges had the lowest emergence in representative species. Percentage of species with long growth cycle was highest in both sites.展开更多
Seed sizes of 74 woody species, including 40 trees and 34 shrubs, of middle subtropical evergreen broad-leaved forest in Mt. Jinyun were investigated and the likely mechanism of seed size variation was analysized. The...Seed sizes of 74 woody species, including 40 trees and 34 shrubs, of middle subtropical evergreen broad-leaved forest in Mt. Jinyun were investigated and the likely mechanism of seed size variation was analysized. The results showed that: 1) There was considerable variance in the seed length and great variance in the seed weight among the 74 species. The maximum seed length was 100 times greater than the minimum. The lengths of most seeds were in a range of 0.1～1 cm, accounted for 71.62% of the total species. The maximum seed weight was 10 000 times greater than the minimum. A 39.41% of species had their 1 000 seed weights in a range of 10～100 g. 2) The results of statistic analysis indicated the seed sizes were influenced by their habitats. The longest seeds were born in canopy layer, the middle in forest edge & understorey and the shortest in dankness habitat. Additionally, the seed sizes were also influenced by growth forms of species. The seed sizes gradually decreased with the growth forms sequence of large tree, middle tree, small tree, large shrub and small shrub. Moreover, the phylogenetic backgrounds of species had little influences on the seed sizes. Little correlations were found between seed sizes and their orders, families, taxonimical groups with the different weight ratio of endosperm and different fruit types.展开更多
文摘The present study was conducted in the alpine pastures of Tungnath （30° 14＇ N and 79° 13＇ E） to observe life-form and growth-form patterns of alpine plant species under grazed and ungrazed conditions and to work out the plant life form spectrum. Species were categorized as plant habit, height and length of growth-cycle and life-form classes according to Raunkiaer＇s system. The results show that in total of 68 species at grazed site, hemicryptophytes （He） accounted for 50.00% species, followed by cryptophytes （26.47%）, chamaephytes （16.18%）, phanemphytes （4.41%） and therophytes （2.94%）. At the ungrazed site in 65 plant species, hemicryptophytes （He） accounted fo＇r 49.23% species, cryptophytes （26.15%）, chamaephytes （15.38%）, phanerophytes （6.15%） and ther6phytes （3.08 % species）. In general, hemicrptophyte are dominant^in both sites i.e. graged and ungrazed. Growth form categories were classified as forbs, shrubs, grasses and sedges＇and undershrubs, according to plant habit and height. On the basis of length of the growth cycle, species were categorized as plant species of short growth cycle, intermediate growth cycle and long growth cycle. The short forbs of plant habit and height, had the highest emergence, and grasses and sedges had the lowest emergence in representative species. Percentage of species with long growth cycle was highest in both sites.
文摘Seed sizes of 74 woody species, including 40 trees and 34 shrubs, of middle subtropical evergreen broad-leaved forest in Mt. Jinyun were investigated and the likely mechanism of seed size variation was analysized. The results showed that: 1) There was considerable variance in the seed length and great variance in the seed weight among the 74 species. The maximum seed length was 100 times greater than the minimum. The lengths of most seeds were in a range of 0.1～1 cm, accounted for 71.62% of the total species. The maximum seed weight was 10 000 times greater than the minimum. A 39.41% of species had their 1 000 seed weights in a range of 10～100 g. 2) The results of statistic analysis indicated the seed sizes were influenced by their habitats. The longest seeds were born in canopy layer, the middle in forest edge & understorey and the shortest in dankness habitat. Additionally, the seed sizes were also influenced by growth forms of species. The seed sizes gradually decreased with the growth forms sequence of large tree, middle tree, small tree, large shrub and small shrub. Moreover, the phylogenetic backgrounds of species had little influences on the seed sizes. Little correlations were found between seed sizes and their orders, families, taxonimical groups with the different weight ratio of endosperm and different fruit types.
