Abstract:

Taking 65 plant species in the elm forests of sand dunes in Xianghai Natural Reserve of western Jilin Province as the research object, the weights of plant propagules (19 kinds of seeds, 46 kinds of fruits) were compared, and the functional differences of reproductive strategies of different plant types in semi-arid habitat and their roles in the evolution of vegetation regeneration were analyzed. The results indicated that the individual weight of plants whose propagules were seeds was divided into 4 groups (<0.1, 0.1-1, 1-10, and 10-100 mg), the individual weight of plants whose propagules were fruits was divided into 5 groups (<0.1, 0.1-1, 1-10, 10-100, and 100-200 mg). The weight per seed or fruit of the plant propagules varied greatly, from 0.0096 mg for the lightest seed of Orobanche coerulescens to 131.50 mg for the heaviest fruit of Tribulus terrestris. The plant species, such as Chenopodium aristatum, Agrostis clavata, Typha minima, Artemisia lavandulaefolia, Chenopodium acuminatum, Setaria viridis, Taraxacum mongolicum, Calamagrostis epigejos, Saussurea amara and Ixeris chinensis, could distribute widely in the Xianghai Natural Reserve on account of the lighter weight of propagules with the help of wind dispersal. Moreover, the plant species, such as Chenopodium aristatum, Orobanche coerulescens, Puccinellia tenuiflora, Potentilla discolor, Chenopodium acuminatum, Silene jenisseensis, Plantago depressa, Lythrum virgatum, Setaria viridis, Thymus serpylium, Polygonum thunbergii, Thalictrum simplex, Galium verum and Sium suave, could be of persistent soil seed banks on account of the lighter weight (<1 mg) and approximate spherosome shape of propagules. In semi-arid sandy areas, plants form special reproductive strategies with the help of propagule morphology, which reduces the risk of population survival to a certain extent and has an important ecological significance for sustainable population reproduction.

Key words: propagule, individual grain weight, soil seed bank, reproductive strategy, desertification, vegetation restoration