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Earlier modeling has suggested that long distance gene flow is of importance in increasing the adaptability of tree populations in a changing climate. In times of warming temperatures, early flowering phenotypes may be favored, because early flowering may be connected to early onset of growth. Long term direct measurements of flowering, pollen cloud and intrapopulation fecundity variations are needed to test this hypothesis. Having one of the furthest transported types of pollen grains, birch may have good potential for long distance gene flow. Our daily observations over eight years, of 30 silver birches (Betula pendula Roth), showed that the onset and duration of flowering phenology was determined by the accumulation of spring temperature sums, but the window for potential long distance gene flow was narrow. The interannual phenology variations were large, the order of timing of female and male catkins in various trees of this monoecious species tended to differ, and the timing of generative and vegetative spring phenologies were not correlated at tree level. Early flowering trees tended to have a higher variation in germinability than later flowering trees. No other connection between timing of phenology of flowering and seed quantity or quality was found. Although stochastic climatic conditions produce interannually variable phenological windows, probability for long distance gene flow from areas differing in timing of spring temperature accumulations may be low in silver birch. Intertree variations in fecundity were high, and the majority of seeds and pollen were produced by only a few trees. Moreover, the amount of seeds produced was positively related to seed germinability, thus large phenotypic fecundity variations may decrease interannual genetic variations in seed sets. 相似文献
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杜鹃花种子休眠打破技术的研究 总被引：1，自引：0，他引：1
以杜鹃花的两个种映山红（R.simsiiPlanch.）和蓝荆子（R.mucronulatumTurcz.）的种子为实验材料,用不同浓度的硫酸、有机溶剂和氧化剂处理种皮并分别处理不同时间,在培养皿中进行萌发对比实验;用赤霉素、层积及变温处理种子在培养皿中进行萌发的对比实验。结果表明,40%硫酸处理种皮20min、100%乙醚处理种皮20min、5%次氯酸钠处理种皮30min、层积处理及10%赤霉素处理24h均能有效提高映山红种子萌发的发芽率、发芽势和发芽指数;20%硫酸处理种皮10min、层积处理和赤霉素处理能显著提高蓝荆子种子发芽率、发芽势和发芽指数,100%乙醚处理10min能明显著提高蓝荆子种子的发芽率。 相似文献
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Kazunari Nomura Ichitaro Endo Akira Tateishi Hiroaki Inoue Kazuo Yoneda 《Scientia Horticulturae》2001,90(3-4):209-218
The rat’s tail radish (Raphanus sativus cv. “Pakki-hood”), cultivated in the northern part of Thailand, does not require low temperature for flower-bud initiation and shows high germinability even at low temperature. To analyze its characteristic temperature response, seedlings were subjected to a 3 day-chilling treatment at 0°C after a series of incubations for germination at 26°C which ranged from 3 h to 4 days. The chilling treatment after an initial stage (3 h to less than 2 days) of incubation at 26°C did not significantly affect the hypocotyl regrowth, but the same treatment after a more than 2-day incubation at 26°C reduced subsequent hypocotyl growth of plants. 1-aminocyclopropane-1-carboxylic acid (ACC)-dependent ethylene-forming activity was also reduced by the chilling treatment after 2–4-day incubation at 26°C. Electrolyte leakage from tissues of seedlings in the chilling treatment was increased in proportion to the length of the incubation at 26°C, indicating severe damage of chilling to plasma membranes after a longer incubation. We found a transition of chilling-sensitivity at 2 days in the incubation period for germinating seeds of Pakki-hood. Seedlings of Pakki-hood chilled earlier than the transition are relatively unaffected in their subsequent growth, but the seedlings become sensitive to chilling after the transition. 相似文献
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用IDS法处理樟子松（PinusSylvestrisvar,mongolica）种子，发现死种子较活种子拥有较高的含水率．干燥过程中，死种子水分散失速度比活种子快，在干燥到8～10h进行分离可清除27％左右的种粒，使下沉种子的发芽率和活力指数分别从75％和4．39提高到91％和5．85，并且拥有较高的抗低温损伤和高温老化能力。 相似文献
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在不同开花温度（FT）和发芽温度（GT）组合处理下,测定了西葫芦14个自交系的花粉发芽率.结果表明：①随FT和GT的降低,西葫芦花粉发芽力下降.正常GT24 ℃下平均花粉发芽率在48%以上,GT15 ℃下为30%左右,GT9 ℃下发芽率极低,接近零,FT和GT的影响都达到极显著,但GT影响较大,FT和GT交互作用不显著.②不同的FT和GT组合下,自交系间花粉的发芽率除FT15 ℃/GT24 ℃下差异不显著,其他FT（15 ℃、12 ℃、9 ℃）和GT（24 ℃、18 ℃、15 ℃、12 ℃、9 ℃）的各组合温度下,都达到了极显著差异.③在FT9 ℃/GT12 ℃培养时,自交系间方差分析的F值最大,且变异系数最大,花粉发芽力的差异达到最大,说明该温度组合可作为鉴定西葫芦不同品系（种）耐冷性的适宜花粉培养温度. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):378-384
Abstract During long-term storage, Scots pine (Pinus sylvestris L.) seeds are susceptible to ageing, leading to declined vigour and poor germinability. To characterize biochemical changes associated with this ageing, vitamin E and fatty acid compositions of Scots pine seeds stored for 3–31 years were analysed. The seeds contained seven homologues of the vitamin E family: α-, β-, δ- and γ-tocopherols (T) and α-, δ- and γ-tocotrienol (T3). The major tocopherol was γ-T, constituting on average 62.1% of total vitamin E. Total vitamin E concentration was markedly lower in older seeds, e.g. 21-year-old seeds contained 52% less vitamin E than the reference for high-quality seed. The α-T concentration was affected the most by seed age, whereas the γ-T concentration decreased more gradually and the concentrations of the other E vitamers seemed to remain relatively constant during natural ageing. Ageing also induced changes in the fatty acid composition of the seeds, e.g. a 29.6% reduction in the unsaturation/saturation ratio. These biochemical changes were associated with decreased germinability and increased electrolyte leakage. 相似文献
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库存野生稻种质资源发芽力研究 总被引：1，自引：0，他引：1
[目的]为种质库贮藏野生稻种子及其他作物种子发芽力监测、方法制定提供科学依据。[方法]对在种质库中贮藏21～28年的2177份野生稻资源种子的发芽率进行监测,分析不同类型的野生稻种子贮藏后发芽率的变化情况。[结果]在中期库贮藏24～28年后的野生稻种子发芽率下降差异极明显,贮藏28年的药用野生稻种子平均发芽率从50.56%下降至11.34%;在长期库贮藏21～27年的普通野生稻、药用野生稻和外国野生稻各种种子平均发芽率下降差异不显著,同一类型不同编号的野生稻种子同时入库贮藏后种子发芽率变化有差异。[结论]野生稻种质资源在长期库中贮藏比在中期库贮藏效果好,寿命长,能安全保存24年以上。 相似文献
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