关键词: 油茶, 种子性状, 浸种, 内源激素

Abstract:

【Objective】This study investigated the seed characters of Camellia oleifera and analyzed the changes in water absorption and the absorption rate to explore changes in endogenous hormones during seed soaking and to provide a technical support for standardized rootstock cultivation. 【Method】Seeds of C. oleifera cultivars: ‘Changlin 3’, ‘Changlin 4’, ‘Changlin 18’, ‘Changlin 40’ and ‘Changlin 53’ were used in experiments to determine seed shape parameters and volume. In an artificial climate chamber with the fixed temperature and humidity, the water absorption and absorption rate at different times during seed soaking were determined for all the cultivars. In a separate experiment, Changlin 18 was subjected to seed soaking at different times and temperatures and the concentrations of gibberellin (GA₃), abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA) were determined using LC-MS and compared by one-way ANOVA. 【Result】The seed volume was in the order as follows: Changlin 53, 40, 18, 3 and 4. Changlin 53 showed a significant variance in relation to the other cultivars. The three-dimensional coefficients of the seeds indicated that they were mostly flat for Changlin 3, 4 and 40 and nearly spherical for Changlin 18 and 53, which were significantly correlated with the transverse diameter length of the seeds. The seed volume of Changlin 3 and 4 was significantly or very significantly positively correlated with longitudinal and transverse diameters and there was a significant negative correlation with the cross diameter and seed volume between Changlin 40 and 53. There was significantly correlated with the seed volume between Changlin 40 and 53. The water absorption and absorption rate of each cultivar gradually stabilized after 48 h of seed soaking. Water absorption by Changlin 53 seeds was the highest than by Changlin 40 seeds, the lowest during 0-21 h of seed soaking. From 21-48 h of seed soaking, water absorption was in the order: Changlin 4, 3, 53, 40 and 18. The water absorption rate of Changlin 40, 4, 3, 53 and 18 was highest values within 10 h. There was no significant difference between cultivars in the germination rate (P < 0.01 and P< 0.05) after seed soaking, and the order was: Changlin 4, 40, 53, 3 and 18. The concentration of GA₃ increased gradually after seed soaking in Changlin 18 and reached its highest value (0.39 mg/kg) in 2 d. The highest values for SA and JA were 0.058 and 1.77 mg/kg, respectively, reached in 4 d. There were the highest values with 0.050 mg/kg in 2 and 5 d, while there were the lowest values with 0.014 mg/kg in 4 d. During seed soaking, a continuously high m(GA₃)/m(ABA) level was noted in 1 d and 4 d. The highest value for m(GA₃)/m(JA) were reached in 1 d and the lowest values in 4 d. The value for m(GA₃ + SA)/m(ABA + JA) decreased with an increase in seed soaking time. The soaking temperature for Changlin 18 was optimal from 25-30 ℃, and had a significant effect on improving the concentration of endogenous hormones. 【Conclusion】The shape of seeds of C. oleifera cultivars was significantly affected by the transverse diameter. There was high uniformity in seeds of Changlin 18 which were stable in the water absorption and absorption rate. The water absorption and absorption rate reached stability after 48 h during seed soaking, which promoted high hormone concentrations for the germination of seeds. The seed soaking temperature was optimal for seed germination under 30 ℃. The results provide a theoretical basis for the standardized cultivation of C. oleifera rootstock.

Key words: Camellia oleifera, seed character, seed soaking, endogenous hormones