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榕(FicusmicrocarpaL.)和黄桷树(FicusvirensAit.var.sublanceolata(Miq.)Corner)是在三峡库区广泛栽植的优良绿化树种。在三峡库区诸多公路、铁路修建和移民搬迁城镇建设等工程建设后的生态恢复和环境改善中,需要大量的榕和黄桷树。榕和黄桷树的繁殖通常采用切枝扦插的营养繁殖方式进行。因种苗培育的需要,对榕和黄桷树进行切枝时常发生,并且为了尽快获得大的种苗,通常切取榕和黄桷树植冠下部的大枝条用于种苗培育。切枝导致植株大量光合叶组织损失,对榕和黄桷树的总体光合生产和生物量积累会发生影响,同时,也会影响新枝的生长和发生数量以及植株再次提供切枝的能力。为了明确切枝对榕和黄桷树生长的影响,对切枝后榕和黄桷树的生物量积累和枝供给进行了研究,目的在于阐明在三峡库区亚热带气候条件下,生长速度比较快的榕和黄桷树是否可以在每年1次的切枝后很好恢复,从而能够可持续地提供切枝用于种苗培育。实验中对榕和黄桷树1a切枝1次,连续进行了3a。实验共设置了4个切枝强度(从植冠下部开始,分别切去植冠长度0%(对照)、20%、50%和70%范围内的所有枝条)和两个切枝处理季节(春季切枝和秋季切枝)。实验结果表明,切枝会减少榕和黄桷树地上部分生物量增量,生物量增量减少的程度与切枝强度呈正相关;并且,每年连续进行的切枝使地上部分生物量增量减少加剧。实验发现,在20%、50%和70%的3个切枝强度中,高切枝强度可以保证在第1次切枝处理中获得高的枝收获量,但并不能保证在第2次和第3次切枝处理中也能获得高的枝收获量。与春季切枝处理相比,秋季切枝处理使榕和黄桷树获得更高的地上部分生物量增量,从而获得更高的枝收获量。就植株地上部分生物量增量和枝收获量而言,切枝强度对二者的影响并不因切枝季节不同而表现出差异。研究表明,对于本实验研究中采用的榕和黄桷树植株,当切枝强度高于20%时,每年1次的切枝不能使榕与黄桷树植株的生长完全恢复。如果切枝每年进行1次,为保证能够可持续地获得切枝并且对植株的生长不造成过大影响,对于本研究中所采用的榕和黄桷树植株而言,最适的切枝强度应低于20%。
Ficus microcarpa L. and Ficus virens Ait. Var. Lablanceolata (Miq.) Corner) are excellent tree species widely planted in the Three Gorges reservoir area. In the Three Gorges Reservoir area many roads, railway construction and relocation of urban construction and other projects after the construction of ecological restoration and environmental improvement, the need for a large number of banyan tree and yellow. Ficus and yellow emu tree propagation is usually cuttings cuttings vegetative propagation. Because of the need of seedling cultivation, the cutting of Ficus and Betula fargesis occurs frequently, and in order to obtain large seedlings as soon as possible, it is common to cut large branches of the lower part of Ficus and Betula platyphylla for seedling cultivation. Cuttings lead to the loss of a large number of photosynthetic leaf tissues of plants, affecting both the overall photosynthetic production and biomass accumulation of the fig and the P. przewalskii trees. In addition, they affect the growth and occurrence of new shoots and the ability of the plants to provide cuttings again. In order to clarify the effects of shrub on the growth of figs and catharanthes, the biomass accumulation and shoot supply of figs and figs were studied in order to elucidate the effects of the growth of Ficus and Ficus in the subtropical climatic conditions in the Three Gorges Reservoir Area Whether or not the tree can recover well after a single annual cut can provide a sustainable cutover for seedling development. Experiments in the banyan and Ipomoea Ia cut 1, continuous for 3a. A total of 4 cuttings were set up in the experiment, starting with the lower part of the canopy, cutting off all the branches within the range of 0% (control), 20%, 50% and 70% Spring cuttings and autumn cuttings). The experimental results showed that the cuttings could reduce the aboveground biomass increment and the decrease of biomass increment, which was positively correlated with the cutting strength; furthermore, the annual cuttings increased the increment of aboveground biomass incrementally . It was found that high shear strength at 3, 20, 50, and 70% of the three cuttings achieved high shoot yields at the first cut but did not guarantee that at the second and The third cropping also achieved high crop yields. Compared with the spring cuttings treatment, the autumn cuttings treatment increased the above-ground biomass increment of the figs and the mulberry trees, resulting in higher shoot yield. In terms of above-ground biomass increment and shoot yield, the effects of cutting intensity on the two did not differ due to different cutting seasons. Studies have shown that when the cuttage intensity is higher than 20%, the annual cuttings can not completely restore the growth of the figs of Ficus and Betula platyphylla in the plants of the figs and the plants of the figs. If the cuttings are done once a year, to ensure that cuttings can be obtained sustainably and with no significant effect on the growth of the plants, the optimal cut-off strength for the figs and yellowgum trees used in this study should Below 20%.