SEED DORMANCY IN TRILLIUM CAMSCHATCENSE (MELANTHIACEAE) AND THE POSSIBLE ROLES OF LIGHT AND TEMPERATURE REQUIREMENTS FOR SEED GERMINATION IN FORESTS
SEED DORMANCY IN TRILLIUM CAMSCHATCENSE (MELANTHIACEAE) AND THE POSSIBLE ROLES OF LIGHT AND TEMPERATURE REQUIREMENTS FOR SEED GERMINATION IN FORESTS
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DOI：
10.3732/ajb.1000151
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发表时间：
2011-02-01
影响因子：
3
通讯作者：
Hidayati, Siti N.
中科院分区：
文献类型：
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作者：
Kondo, Tetsuya;Mikubo, Makoto;Hidayati, Siti N.
研究前提：一些温带植物的种子需要多次处理才能打破复杂的休眠形式，如深单双形态生理休眠（MPD），但对这一水平的MPD的胚胎生长和胚根和子叶的萌发尚未进行深入的研究。在这里，我们研究了camschatcense，一种据称具有这种MPD的物种，它对栖息地破碎化和森林边缘的补充减少很敏感。方法：5年来在日本北海道采集苦参种子并进行实验。在实验室条件下，跟踪了胚胎的生长、胚根和子叶的出现与田间温度的关系，以确定这些阶段的特定温度和光照需求。主要结果：低温（冬季）克服了未发育胚的休眠，胚生长和胚根萌发发生在种子传播后约1年的7 - 9月。根茎在狭窄的温度范围（20 -25摄氏度）、黑暗和恒定的温度下生长得最好。根在第二个秋天长出来了。子叶需要第二次低温（第二个冬天）才能从有根的种子中萌发出来，这一过程发生在4月份，在扩散后1.5年多一点。结论：苦参种子具有深层的简单双MPD，其萌发条件为黑暗和恒温。在生态学上，森林的边缘可能对该物种的发芽有害，因为与森林内部相比，森林的边缘光照增加，温度波动更大。因此，这些特殊的要求可能对降低这种植物在森林边缘的种子萌发起重要作用。
Premise of the study : Seeds of some temperate plants require multiple treatments to break complex forms of dormancy, such as deep simple double morphophysiological dormancy (MPD), but embryo growth and radicle and cotyledon emergence have not been studied in depth for this level of MPD. Here we studied Trillium camschatcense, a species that is purported to have this MPD and that is sensitive to habitat fragmentation with decreased recruitment at forest edges.Methods : Trillium camschatcense seeds were collected and experiments conducted in Hokkaido, Japan over 5 years. Growth of embryos and emergence of radicles and cotyledons were tracked in relation to field temperature to determine specific temperature and light requirements for these stages under laboratory conditions.Key results: Low (winter) temperatures overcame dormancy in the underdeveloped embryos, and embryo growth and radicle emergence occurred between July and September, ca. 1 year after seed dispersal. Radicles emerged optimally over a narrow temperature range (20 -25 degrees C), in darkness, and at constant temperatures. Roots developed during the second autumn. Cotyledons needed a second low temperature (second winter) to emerge from seeds with roots, doing so in April, slightly over 1.5 years after dispersal.Conclusions: Seeds of T. camschatcense have deep simple double MPD and requirements for radicle emergence: darkness and constant temperatures. Ecologically, edges of forests may be deleterious for germination of the species due to increased light and to higher temperature fluctuations as compared to the interiors of forests. Thus, these specific requirements may play an important role in reducing seed germination of this plant at forest edges.