PJB-2020-212
SEED DORMANCY AND GERMINATION OF MANGLIETIA CRASSIPES Y. W. LAW (MAGNOLIACEAE)
AI-HUA WANG
Abstract
Manglietia crassipes, a “critically endangered” species narrowly distributed in the Dayao Mountain of Guangxi, China, is also a species of ornamental interest, whose variability has not been explored. Key factors leading to its endangerment has not been studied. Here, two experiments were conducted to test the effects of different hormones and different storage conditions of seeds on germination characteristics of M. crassipes seeds. First, we measured the fruit morphology and tested the germination characteristics of the fresh mature seeds, in order to know its natural seed vigour. Meanwhile, effects of hormones treatment (soaking the seeds in distilled water as the control, GA3/ 6-BA/ IAA solutions of different concentrations for 48 h) on natural seed germination were tested. Second, effects of different storage conditions of seeds (constant temperature at 4°C, −7°C, −20°C, 25°C for 100 days, wet stratification at 4°C for 100 days) on seed germination were investigated. Results showed that the abortive rate of the mature fruits was high (28.9%) and fresh natural seeds had a low germination rate (G) and germination index (GI). Different hormones had different effects on seed germination characteristics. Seed germination was inhibited with 6-BA at all concentrations but with IAA only at less than 100 mg/L, otherwise IAA slightly promoted seed germination. GA3 broke seed dormancy and significantly accelerated seed germination by improving G, GI, and IGT, especially over 2500 mg/L. The viability of seeds declined no matter how they were stored. However, 4°C wet stratification storage was preferable for seed vigour and germination energy. Our findings suggest that the high abortive rate of fruits, low germination of the natural seed, seed dormancy and its intolerance to storage, contributed to the endangerment of M. crassipes. And GA3 can break its seed dormancy, which can benefit for its future ornamental breeding and further protection or conservation.
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