文献类型：期刊文献

中文题名：云南红豆杉新采收种子的形态与离体胚的萌发特性

英文题名：Morphology of fresh seeds and germination of in vitro embryos for Taxus yunnanensis

作者：卞方圆[1] 苏建荣[1] 刘万德[1] 李帅锋[1] 郎学东[1]

机构：[1]中国林业科学研究院资源昆虫研究所

年份：2015

卷号：35

期号：24

起止页码：8211-8220

中文期刊名：生态学报

外文期刊名：Acta Ecologica Sinica

收录：CSTPCD;;Scopus;北大核心:【北大核心2014】；CSCD:【CSCD2015_2016】；

基金：林业局948项目(2011-4-03);云南省科技计划项目(2011CI072)

语种：中文

中文关键词：云南红豆杉;形态学;离体胚培养;种子萌发;休眠类型

外文关键词：Taxus yunnanensis; morphology; in vitro embryo culture; seed germination; dormant type

分类号：S791.49

摘要：通过云南红豆杉新采收种子形态观察、透水性测定、种子大小以及所带胚乳多少对离体胚萌发率的影响等试验,探讨云南红豆杉种子的休眠与萌发机理。结果表明,云南红豆杉种子呈倒卵形和三棱形;胚酒瓶形,白色;胚乳淡黄色,油质。种子千粒重为72.934g;种皮、种仁和种胚分别占种子鲜重的50.56%、40.45%和8.99%;胚与种子的体积比(E∶S)为0.074。胚的体积为0.156—1.012mm^3,种子为51.658—109.649mm^3,两者呈显著正相关(P<0.05,r=0.810)。完整种子的吸水率明显低于破裂种皮、酸蚀40min和酸蚀20min的种子,但差异随着浸泡时间延长而缩小;种子含水量饱和时,完整种子、破皮种子与酸蚀种子的吸水率无显著差异(前者为23.7%,后两者约28.0%)。不同大小种子离体胚的萌发率差异显著(P<0.05),特大、大、中、小和特小种子的离体胚的萌发率为80%、77.8%、67.5%、62.0%和44.0%。胚乳抑制离体胚的萌发,不带胚乳离体胚的萌发率为41.3%,显著高于带胚乳的萌发率(P<0.05),带部分胚乳的胚为9.7%—13.3%,带全胚乳的胚为0。同时离体胚培养过程中所用种胚的新鲜程度也严重影响胚的萌发率。云南红豆杉种子休眠属于中度生理休眠类型,种子中的抑制物质含量随时间的动态变化和胚乳中抑制物质含量的多少对胚萌发率的影响是以后云南红豆杉休眠研究的重点。
Taxus yunnanensis （Taxus wallichiana var. wallichiana） is an endangered species on China＇s national protection list. This plant is located mainly in Yunnan, Sichuan, Chongqing, and Tibet. In nature, the seeds of T. yunnanensis need about 2 years to eliminate dormant factors for germination. To shorten the time of seed germination and improve the germination rate, many studies of seeds on biology, physiological ecology, and cultivation have been conducted. However, there are no consistent views and conclusions about how to improve germination rates. Thus, clarification of the embryonal germination characteristics and the water permeability of seed coats form the basis for understanding causes of seed dormancy. In order to explore the mechanisms of T. yunnanensis seed dormancy and germination, fresh seeds were used for morphological observation, water permeability tests, and tests on the effects of different seed sizes and endosperm quantities on the germination rate for in vitro embryos. Our results showed that T. yunnanensis seeds were obovate three-sided prisms, embryos were white and bottle shaped, and the endosperm was pale yellow and oily. One thousand seeds weighed 72.934 g. The relative weights of seed coat, kernel, and embryo accounted for 50.56%, 40.45%, and 8.99% of total seed weight, respectively. The volume ratio of an embryo versus a seed （E ：S） was 7.4%. The volume range for embryos and seeds was 0.156-1.012 and 51.658-109.649 mm3, respectively. Mantel tests showed that there was a significant positive correlation between the volume of embryos and that of seeds （P〈0.05, r= 0.810）. The water absorption rate of intact seeds was lower than that of cut seeds. However, the differences of water absorption rates for seeds corroded by acids for 40 and 20 min were reduced with the extension of soaking time. When the moisture content of a seed was saturated, there was no significant difference of water absorption rate among intact （ 23.7%）, cut （ 28.7% ）, and acid-corroded （28.0%） seeds. The germination rate of in vitro embryos was markedly different for different seed sizes （P〈0.05）. Specifically, the germination rate of in vitro embryos for superlarge seeds （98.051-109.649mm3） , large seeds （86.453-98.050mm3） , medium seeds （74.855-86.452 mm3）, small seeds （63.257-74.854nma3） , and supersmall seeds （51.658-63.256mm3） was 80%, 77.8%, 67.5%, 62.0%, and 44.0%, respeetively. Moreover, the endosperm inhibits the germination of embryos, and the germination rate of embryos without endosperm （41.3%） was significantly higher than that for embryos with endosperm （P〈 0.05）. The respective germination rates for seeds with a portion of the endosperm and full endosperm was 9.7%-13.3%, and 0%. Finally, the freshness of in vitro embryos also affected their germination rates. In conclusion, the present study showed that sampling materials and their cultivation conditions should be consistent between studies. In addition, the seed dormancy of T. yunnanensis was moderate and caused by physiological dormancy. Many factors can contribute to physiological dormancy; this study confirmed that inhibitors within seeds are the most important causes of T. yunnanensis seed dormancy. Additional studies should focus on the changes in quantity of inhibitors over time and their effects on the germination rates for in vitro embryos.