中国特有植物凹叶木兰种子的休眠与贮藏行为

唐安军*
重庆师范大学生命科学学院, 重庆401331

通信作者:唐安军;E-mail: tanganjun@mail.kib.ac.cn;Tel: 023-65910315

摘 要:

凹叶木兰(Magnolia sargentiana)是中国特有的观赏树木, 种群的自然更新很差, 须阐明其原因。研究发现, 凹叶木兰种子的胚很小, 无论是否被植物生长调节剂预处理, 在冷层积(4 ℃)和暖层积(15 ℃)过程中, 胚在种子内逐渐生长发育成熟, 并能在多个温度下萌发, 以变温30 ℃/20 ℃为最适宜。由此可见, 凹叶木兰种子不能萌发的直接原因是形态休眠。此外, 凹叶木兰种子较耐脱水, 但干燥脱水至含水量为7.1%和5.3%时, 种子的存活率分别是78.3%和40%。保存6个月后, 含水量为9.4%或7.1%的种子在–20 ℃下全部失活, 而在0和4 ℃下的种子, 存活率无显著变化, 充分证实凹叶木兰种子是中间性的。

关键词:形态休眠; 层积处理; 种子萌发; 中间性种子; 凹叶木兰

收稿:2013-09-22   修定:2013-11-11

资助:重庆市科委科技项目(cstc2013jcyjA00002)、国家自然科学基金(31171588)和重庆师范大学校级科技项目(2011SLX34)

Seed Dormancy and Storage Behavior of Magnolia sargentiana Endemic to China

TANG An-Jun*
College of Life Sciences, Chongqing Normal University, Chongqing 401331, China

Corresponding author: TANG An-Jun; E-mail: tanganjun@mail.kib.ac.cn; Tel: 023-65910315

Abstract:

It has been found that the natural regeneration of Magnolia sargentiana, an ornamental endemic to China, is highly poor, which is worth investigating cause. Embryos in mature M. sargentiana seeds are extremely small. The embryos markedly grew in the process of both cold (4 ℃) and warm stratification (15 ℃) regardless of plant growth regulator pretreatment of GA3 and 6-BA solutions, and germinated at a range of temperatures, 30 ℃/20 ℃ of which was optimal. These data illustrated that morphological dormancy is caused by an underdeveloped embryo that must mature prior to germination. In addition, M. sargentiana seeds could tolerate desiccation to a limited extent. The seed survival rates were 78.3% and 40% at 7.1% and 5.3% of water contents, respectively. When the seeds with 9.4% or 7.1% of water content were conserved at –20 ℃ for 6 months, they completely lost viability. However, if the same seeds were hermetically stored at 0 ℃ and 4 ℃ for 6 months, their viability was almost unchanged. These results fully confirm that M. sargentiana seeds are intermediate.

Key words: morphological dormancy; stratification treatment; seed germination; intermediate seeds; Magnolia sargentiana

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