Subjects: Biology >> Botany submitted time 2022-12-29 Cooperative journals: 《广西植物》
Abstract：
To explore the population quantitative characteristics and regional distribution of wild Viburnum plants in southwest Hubei, and reveal the survival status and development trend of the following five Viburnum species: V. erosum, V. betulifolium, V. sympodiale, V. setigerum and V. dilatatum. A total of 27 hm2 permanent monitoring stands were set up in Jinzishan National Forest Farm, Mulinzi National Nature Reserve and Qizimei Mountain National Nature Reserve in southwest Hubei. The age structure, dynamic quantitative analysis and static life table of five Viburnum species were used to explore the population structure, dynamic characteristics and future development potential of Viburnum plants. The results were as follows: (1) The distribution area and population size of Viburnum plants in southwest Hubei are significantly different. (2) The age structure of the five Viburnum species displays as the pyramidal type summarized from population structure and dynamic analysis.. The number of individuals of each population is large at the young stage (89.48% of V. erosum in Jinzi Mountains, 76.38% of V. betulifolium, 67.24% of V. erosum in Mulinz, 62.11% of V. dilatatum, 56.53% of V. sympodiale, 58.44% of V. setigerum), and only a small proportion of individuals (0.18% of V. erosum in Jinzi Mountains, 0.85% of V. betulifolium, 3.29% of V. erosum in Mulinz, 3.97% of V. dilatatum, 8.37% of V. sympodiale, 2.79% of V. setigerum) in the older stage. The young stage plants of five Viburnum species all have strong growth potential but are sensitive to external disturbances. (3) The survival quantity of the five Viburnum species is decreasing monotonically with increasing age class presented by static life tables. Except for V. setigerum, the life expectancy reaches peak at the younger age, all other Viburnum species populations reach the peak at the middle age. The change trend of mortality rate and disappearance rate are similar, but the fluctuation of disappearance rate and mortality curve are different among different species. The survival curves are tended to be Deevey-Ⅱ type. (4) The four survival function curves show that all five Viburnum species populations exhibited a substantial decrease in the early stage, stabilization in the middle stage, and decline in the late stage. To sum up, Viburnum species are abundant plant resources in southwest Hubei. Therefore, it is scientific and feasible to exploit Viburnum plants rationally. In the young stage, artificial thinning can be carried out appropriately to improve the preserving rate. During the stable middle stage, the dominant and species which have good ornamental characters can be selected for appropriate development and utilization. However, some species need to be protected to maintain biodiversity in this area.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-11-04 Cooperative journals: 《广西植物》
Abstract： To explore whether the allelopathy of Metasequoia glyptostroboides litter is an obstacle to its natural regeneration, eight concentrations (200, 100, 50, 20, 10, 5, 2, 1 g·L-1 and CK) of aqueous extracts from fresh andnatural litter of M. glyptostroboides were set to analyze the allelopathic effects of aqueous extracts from different types and concentrations on seed germination and growth of M. glyptostroboides. The results were as follows: (1) The aqueous extract of the fresh M. glyptostroboides litter had no significant effect on seed germination rate and germination potential (P>0.05), but had significant effect on germination index (P<0.05), and seed germination was significantly inhibited by 1, 100, 200 g·L-1 treatments. The effects of aqueous extract of the natural M.glyptostroboides litter on three indexes of seed germination were not significant (P>0.05), but the inhibitory effect was reflected in 5, 10, 50, 200 g·L-1. (2) The shoot length, hypocotyl and primiary root length of M.glyptostroboides seeds were significantly different between different concentrations of fresh and natural litter aqueous extracts (P<0.05), and decreased gradually with the increase of aqueous extract concentration (≥10 g·L-1), especially in the range of 50~200 g·L-1. (3) Compared with seed germination, the aqueous extracts of fresh and natural M. glyptostroboides litter had stronger inhibitory effect on the growth of seeds after germination, and the allelopathic effect of fresh litter was stronger than that of natural litter. (4) The primary root length was the most sensitive to allelochemicals among seed germination and growth indexes. (5) The dynamic change of shoot length growth of M. glyptostroboides seeds accords with the “S” growth curve (R2≥0.988). The litter of M. glyptostroboides had a certain allelopathic inhibitory effect on its own seed germination and growth, which affected the natural regeneration of its population. It was suggested that the litter under the forest should be properly cleaned to promote the natural renewal of the M. glyptostroboides population in the management of M. glyptostroboides populations.
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