紫楠种子休眠原因和快速解除方法研究

Studies on the Causes of Seed Dormancy of Phoebe sheareri and Rapid Removal Methods

摘要:

通过了解紫楠(Phoebe sheareri)种子休眠原因，采取机械、酸碱腐蚀、层积处理(5 ℃~25 ℃)等措施研究解除种子休眠的最佳方法。结果表明，种皮透水性差是抑制紫楠种子萌发的主要原因，种子休眠类型为物理休眠。酸碱腐蚀处理未能有效促进种子的萌发，浓硫酸和氢氧化钠处理种子不同时间(1~25 min)后，种子发芽率提高了33%~55%，但种子出现严重的伤害现象，其腐烂率高达30%~97%。机械处理和层积处理均能有效打破种子的休眠，其中机械处理以去种皮处理效果最好，种子发芽率和发芽势分别提高了99.33%和76.00%，但操作耗时、费力。层积处理以25 ℃暖温层积45 d、25 ℃/15 ℃和5 ℃/ 25 ℃/5 ℃变温层积60 d效果较好，其发芽率达89%~93%，发芽势达79%~83%，且各层积处理间发芽率、发芽势没有差异；但与暖温层积相比，变温层积所需层积时间更长，种子腐烂率更高。25 ℃暖温层积45 d是破除紫楠种子休眠的最佳方法。

Abstract:

By understanding the causes of seed dormancy of Phoebe sheareri, mechanical, acid-alkali corrosion and lamination treatment (5 ℃-25 ℃) were used to study the best methods to relieve seed dormancy. The results showed that the low permeability of seed coat was the main reason for inhibiting seed germination, and the seed dormancy type was physical dormancy. Acid and alkali corrosion treatments could not effectively break seed dormancy. After the seeds were treated with concentrated sulfuric acid and sodium hydroxide for different time (1-25 min), the germination rate was increased by 33%-55%, but the seeds were seriously damaged, and the decay rate was as high as 30%-97%. Both mechanical treatment and stratification treatments could effectively break seed dormancy, and removing whole seed coat by mechanical treatment had the best effect, and seed germination rate and germination potential increased by 99.33% and 76.00%, respectively. But this method was time-consuming and laborious. The seeds under 25 ℃ warm stratification for 45 d, 25 ℃/15 ℃ and 5 ℃/25 ℃/5 ℃ variable temperature stratification for 60 d could effectively promote germination, with the germination rate and germination potential increased by 89%-93% and 79%-83%, respectively, and there were no obvious differences in germination rate and germination potential among these types of stratification. However, compared with warm stratification, variable temperature stratification requires longer stratification time and higher seed decay rate. Therefore, 25 ℃ warm stratification for 45 d was the optimal way for breaking seed dormancy of P. sheareri.