杉木种子园衰退母树截干后的生理响应及其复壮效应

发布时间：2018-03-26 20:03

  本文选题：杉木　切入点：种子园　出处：《中国林业科学研究院》2016年博士论文

【摘要】：杉木是我国主要的用材树种,其种子园营建技术水平在我国林木良种选育体系中一直居于领先地位。目前杉木已全面进入第3代育种水平,但是第3代种子园良种供应量尚不能完全满足生产需求。由于早期建设的杉木1~2代种子园大都进入老化衰退期,如何采取有效的技术措施,使老龄衰退种子园母树得以复壮,延长经营期限,已成为林业科技工作者关注和亟需解决的一个技术问题。基于此,本研究以广西全州县咸水林场1987年完成嫁接的杉木第1代种子园老龄衰退母树为研究对象,研究截干后老龄衰退母树的生理响应、复壮效应和经济效益,以期为杉木老龄衰退种子园的持续经营管理提供科学依据。取得的主要结果如下:(1)杉木衰退母树个体在截干后均具萌发能力,约4个月后即可萌发新枝。截面高度是影响新枝萌发的最主要因素,新枝萌发能力与截面高度呈反比,距基部越近越有利于新枝的萌发和生长。对截面进行覆膜保水,可使新萌嫩枝的存活率从40.0%提高到98.0%以上,提高幅度1倍以上。(2)截干后新萌枝条的叶片气孔特征有显著变化,其气孔器长度和宽度一定时期内随枝龄增加呈增大趋势,至枝龄3a时较未截干母树分别提高2.2%~2.8%和2.6%~9.8%。研究同时发现,叶绿素含量与枝条年龄呈正相关关系,枝龄越大则叶绿素含量越高,截干后新萌枝条的枝龄得到幼化,因而叶绿素含量较未截干的老枝低。可溶性糖、淀粉和碳水化合物含量与枝条年龄亦呈正相关关系。超氧化物歧化酶(SOD)与枝龄呈正相关关系,随着枝条年龄的增加而增加,而过氧化物酶(POD)则相反,其含量与枝龄呈负相关关系,此两种酶在枝条中的活性表现为相互抑制的关系,呈此长彼消规律。(3)截干显著促进新萌枝条的光合能力,相较于未截干母树的老枝,截干后所萌发新枝的净光合速率、气孔导度、蒸腾速率和水分利用效率分别提高了123.9%、84.0%、51.8%和22.8%。研究也发现,枝龄越小,其光合能力越强。从枝条方向看,东面枝叶的净光合速率、气孔导度和蒸腾速率均高于南面和西面两个方向,南面次之,西面最差。因此在种子园实际经营过程中,应注意树冠枝条的管理。(4)截干后,在8月生长旺盛期,母树N、P、K、Cu、Zn、Fe和B含量分别平均提高15.3%、17.0%、27.0%、239.7%、62.9%、45.2%和46.3%;在12月生长减缓期,母树N、P、K、Cu、Zn和Fe含量分别平均提高4.6%、11.9%、11.8%、19.4%、15.4%和37.1%,表明截干可以达到促进杉木母树衰退个体复壮的目的。(5)截干可有效促进老龄衰退母树恢复和提高球果产量的能力,种子质量也得到明显改善。母树在截干后的首次挂果即比该种子园近3a产量均值有所增加,增加幅度为35.6%。球果果长和果径分别提高2.9%和1.6%,种子千粒重、优良度、发芽势、发芽率和成苗数量等指标也得到显著提高,提高幅度分别为17.1%、82.7%、134.4%、130.3%和24.9%。同时发现,赤霉素含量与母树或母枝年龄呈负相关关系,与未截干相比,截干母树种子的赤霉素含量更高,提高幅度约12.6%,因而相应的种子发芽效果更好。(6)在遗传基础相对一致的情况下,种子的播种品质将影响子代造林的表现。截干母树种子的播种品质优于不截干母树种子,因而其造林效果相对较好,2a生和3a生时其树高生长量分别提高了4.6%和8.7%。(7)杉木大龄种子园不改造、截干复壮和更新重建3种方式的中短期经济效益综合评价结果显示,截干模式最优,改造不到4a即可获利且逐年超出未改造模式,短期的内部收益率高达33.44%,是重建模式的2.5倍以上,表明截干改造大龄杉木种子园是更新改造过渡期间的一种有效方式。综上所述,对杉木大龄种子园的衰退母树采取截干处理,可使其新萌枝条得到幼化,叶片生理特征得到改善,不但其新萌枝条所结球果、种子产量得到提高,且种子的品质、实际育苗和造林效果也得到相应改善。因此,截干措施对杉木衰退母树的生理响应积极、复壮效应明显。本研究的结果有助于丰富我国林木种子园的实践经验和理论体系。
[Abstract]:Chinese fir is the main timber species in China, the seed orchard level has been in the leading position in China's tree breeding system. At present, Chinese fir has entered the third generation breeding level, but the third generation seed orchard seed supply still can not fully meet the production needs. By 1~2 in the early construction of the Chinese fir seed orchard are enter the aging period of recession, how to take effective measures, make the aging of seed orchard trees to decline and rejuvenation, the extension of the term of operations, has become a technical problem of forestry science and technology workers to pay attention to and solve. Based on this, this study takes Guangxi County State salt water forestry centre completed in 1987 first seed orchard of Chinese fir trees for aging grafting recession the object of study, research on stem cutting after aging physiological responses of the declining trees, rejuvenation effect and economic benefits, in order to sustainable management of Chinese Fir Seed Orchard for aging decline To provide a scientific basis. The main results are as follows: (1) Chinese fir seed germination ability of individuals were out of recession in the stem cutting after about 4 months after germination shoots. The section height is the main factor affecting shoot germination, shoot germination ability and section height is inversely proportional to the distance, the closer the base is conducive to germination the growth of shoots. The section and coated with water, can make new adorable shoots improving survival rates from 40% to 98%, increased by more than 1 times. (2) after cut NEW Adorable branches of stomatal characteristics have changed significantly, the stomatal length and width within a certain period of time with increasing branch age increased, 3a is not to shoot age trees cut stem were increased by 2.2%~2.8% and 2.6%~9.8%. study also found that the relationship between chlorophyll content and shoot age, branch age the greater the higher chlorophyll content, cut dry after new adorable branches shoot age and immature, and leaves The chlorophyll content than the stem cutting old branch is low. The soluble sugar, starch and carbohydrate content of branches and age were positively correlated. Superoxide dismutase (SOD) and branch age positively relationship, increased with increasing branch age, and peroxidase (POD) on the contrary, the content was negatively correlated the relationship with the ages of the two, the activity of enzyme in the branches of the performance of the mutual inhibition, in this long elimination rule. (3) the stem cutting branches significantly promote the new adorable photosynthetic capacity, compared to the non stem cutting trees and old branches, net light cut dry after the shoot photosynthesis rate, stomatal conductance, transpiration rate and water use efficiency were increased by 123.9%, 84%, 51.8% and 22.8%. studies have also found that the branch age is smaller, the photosynthetic capacity is stronger. From the branch direction, the net photosynthetic rate of the East light leaves, stomatal conductance and transpiration rate were higher than that in the South and west two the direction of the south. 娆′箣,瑗块潰鏈，

本文编号：1669365