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1.在耐寒性较差的针叶树种的幼树中,茎干上部对寒冻的抵抗能力远比基部要大得多。另一方面,在极耐寒的针叶树种中,一个茎干的上部和基部之间抵抗寒冻能力的差异,在冬季要变为比较小得多。一般来说,在冬季期间,耐寒树种的形成层是茎干中对寒冻抵抗能力最强的组织。2.冷杉、云杉、铁杉等属大部分顶芽只能忍受-40℃左右的寒冻,与它们的叶子和枝条不同,是这些属抵抗寒冻能力的特征之一。3.罗汉柏、花柏、柳杉、雪松、红杉等属的全部树种都不能抵抗低于-25℃以下的寒冻。4.松属抵抗寒冻能力的幅度很大,于-10℃至-90℃,决定于每个树种原产地的气候条件。 5.在落叶松属的树种中,可以观察到芽的抵抗寒冻能力与其原产地的气候条件之间存在着一种密切的关系。总的来说,原产于严寒气候的针叶树种同生长在温暖气候者相比,前者具有比较高得多的抵抗寒冻能力。原产于喜马拉雅的针叶树种的抵抗寒冻能力,远比北方树种要弱得多。
1. In young trees with poor cold tolerance conifers, the upper part of stems is far more resistant to freezing than the base. On the other hand, in very hardy conifers, the difference in resistance to freezing between the upper and basal stems of one stem becomes much smaller in winter. In general, the formation of hardy species during winter is the most resistant tissue to freezing in stems. 2. Most of the top buds, such as fir, spruce and hemlock, can only tolerate freezing to around -40 ° C, unlike their leaves and branches, which are one of the features that are resistant to freezing. 3. Roebull, cypress, cedar, cedar, redwood and other belong to all species are not resistant to freezing below -25 ℃ below. 4. Pinus resistance to freezing capacity of a large range, at -10 ℃ to -90 ℃, determined by the origin of each species of climatic conditions. 5. In larch tree species, it is observed that there is a close relationship between the resistance to freezing of buds and the climatic conditions of their place of origin. In general, the conifers, native to the colder climates, have a much higher resistance to freezing compared to those grown in warm climates. Conifers native to the Himalayas have a much weaker resistance to freezing than far northern species.