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珍稀濒危植物金丝李种子的休眠机理

张俊杰1,2,韦霄2,柴胜丰2,吴少华1*,邹蓉2,覃信梅2,3,付嵘2,4   

  1. 1福建农林大学园艺学院, 福州 350002;2广西壮族自治区中国科学院广西植物研究所, 广西桂林 541006;3广西师范大学生命科学学院, 广西桂林 541004;4广西大学农学院, 南宁 530004)
  • 出版日期:2018-05-10 发布日期:2018-05-10

Dormancy mechanism of the seeds of a rare and endangered plant, Garcinia paucinervis.

ZHANG Jun-jie1,2, WEI Xiao2, CHAI Sheng-feng2, WU Shao-hua1*, ZOU Rong2, QIN Xin-mei2,3, FU Rong2,4   

  1. (1College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; 2Guangxi Institute of Botany, Guangxi Zhuangzu Autonomous Region and Chinese Academy of Sciences, Guilin 541006, Guangxi, China; 3College of Life Science, Guangxi Normal University, Guilin 541004, Guangxi, China; 4College of Agriculture, Guangxi University, Nanning 530004, China).
  • Online:2018-05-10 Published:2018-05-10

摘要: 珍稀濒危植物金丝李(Garcinia paucinervis)种子的萌发十分缓慢,探讨其休眠机理,可为该物种的种质资源保育与可持续利用提供理论依据。本文对金丝李种子种皮结构及其透水性,剔除部分种皮和胚乳后种子的萌发情况,胚乳和胚等粗提物的活性,储藏、层积和不同温度下种子萌发情况,萌发过程中内源激素含量等进行了研究。结果表明:金丝李种皮无栅栏细胞层,下表面的角质层较薄;种皮对种子的吸胀阻碍小;随着种孔端剔除种皮和胚乳程度的加深,金丝李种子的萌发进程逐渐延长,甚至降低其萌发率,种脐端削除处理对种子萌发影响不大;内果皮、种皮、胚乳和胚中可能存在抑制金丝李种子萌发和生长的内源抑制物;新鲜种子胚率达86.12%,低温层积后胚率无显著变化;低温层积处理延缓其萌发进程,对萌发率无显著影响,4 ℃低温层积是储藏金丝李种子的较好方法;种子萌发对温度敏感,在32 ℃培养下可打破种子休眠,萌发速度显著加快。种子萌发过程中ABA含量降低,GA与ABA、IAA与ABA的比值随种子萌发显著升高,萌发促进与抑制物比例逐渐趋于提高。因此,金丝李种子存在内源抑制物,同时缺乏萌发促进物质,导致生理休眠。该种子休眠特性使其幼苗生长能应对生境的季节变化,种群在风险环境中得以延续,避免大量幼苗竞争。植被破坏导致种子萌发阶段受阻是造成金丝李濒危的原因之一。

关键词: 小兴安岭, 森林沼泽, 非生长季, 采伐干扰, 温室气体

Abstract: The process of seed germination ofGarcinia paucinervis, a rare and endangered plant, is extremely long. Clarifying its dormancy mechanism would provide a theoretical basis for germplasm conservation and sustainable utilization of this species. In this study, we examined the seed coat structure and water absorption characters, the germination of seeds removed part of seed coats and endosperm, the activities of crude extract of endosperm and embryos, seed germination after storage or stratification and under different temperature treatments as well as contents ofendogenous phytohormone during germination. The results showed that the seed coat ofG. paucinervis was mainly composed of parenchymatous layer without palisade layer. The cuticle of abaxial surface was thin. The seed coat had little inhibition to water absorption. With the extent of the elimination of seed coats and endosperm at the side of micropyle, seed germination gradually extended and its germination percentage was even reduced. The treatment of cutting off at the side of hilum had limited effects on seed germination. Endogenous inhibitors for seed germination would exist in endocarp, seed coats, endosperms, and embryos. The embryo rate of fresh seeds reached 86.12%, and showed no significant change after cold stratification. Cold stratificationdelayed seed germination but had no significant effect on germination percentage. Stratification at 4 ℃ was a better method for seed storage of G. paucinervis. Seed germination was sensitive to the changes of temperature. Seed dormancy was broken at 32 ℃, and then the germination was significantly accelerated. During the seed germination, ABA (abscisic acid) content decreased, whereas the ratios of GA (gibberellin) to IAA (indole-3-acetic acid) and GA to ABA significantly increased. The ratios of endogenous accelerants to inhibitors were gradually partial to acceleration. Our results indicated thatG. paucinervis seeds belong to physiological dormancy caused by existence of endogenous inhibitors and lack of germination accelerants. The dormancy characteristics of G. paucinervis seeds would facilitate the responses of seedlings to the seasonal changes of habitats, favor population survive under stress environment, and avoid seedling competition. The barrier of seed germination stage caused by vegetation destruction was one of the reasons for theendangerment ofG. paucinervis.

Key words: greenhouse gas, forested swamp, non-growing season, harvesting., Xiaoxing’an Mountains