ISSR分子标记及其在树木遗传育种研究中的应用

在比较ISSR和其它分子标记的原理和特点的基础上,综述了ISSR分子标记在树木遗传多样性研究、亲缘关系及系谱分析、优良种质和品种鉴定及遗传连锁图谱的构建等领域的研究进展,指出了目前ISSR分子标记在树木遗传改良和辅助育种等研究领域存在的问题,并提出今后的研究方向。     

苹果幼树死亡诱因、诊断与防控

对矮砧苹果新植苗木和2~5年生幼树死亡的原因进行研究,表明苗木失水与轮纹病菌协同危害是主要原因;冻害、根部与主干病害、肥害及苗木质量差是重要原因。生产上及时发现问题,根据不同症状,进行准确的病因诊断,有针对性地采用不同的防控措施:培育不潜带轮纹病菌的苗木;苗木贮运、栽植和管理过程防止失水;栽植前用杀菌剂铲除部分病菌;防止冻害;2~5年生幼树合理肥水管理;防止贪绿徒长;有效地预防根部和枝干病虫害发生。     

Drying half of the root-zone from mid fruit growth to maturity in ‘Hass’ avocado (Persea americana Mill.) trees for one season reduced fruit production in two years

We tested the effect of extended drying of half the root system on fruit yield and fruit Ca concentration, an indirect measure of fruit quality, in avocado (Persea americana Mill. cv Hass). In a field experiment on a sandy soil, withholding irrigation and plastic sheeting was used to dry the root-zone beneath the whole canopy (DD) or half the canopy (WD), compared with well-watered trees (WW). The irrigation water contained added nutrients and was slightly saline. Yield, shoot growth, leaf conductance, leaf and fruit water status and mineral concentrations of leaves and fruit were studied. The responses of treated trees were assessed in the following season during which normal irrigation practices were restored. With respect to yield, the WD treatment behaved the same as the DD treatment. It reduced yield by more than half and proportionately more than the reduction in water supply thus reducing irrigation efficiency. Re-watering did not restore yield of WD or DD-trees in the next season. The WD and DD treatments had no effect on the concentration of Ca in the fruit mesocarp and so are unlikely to affect fruit quality. The main impact of reduced water supply on the trees was fruit abscission and this was linked to dry soil around the roots rather than the water status of the leaves or fruits. We conclude that extended drying of half of the root-zone in one season reduced irrigation efficiency for two seasons by promoting the abscission of developing fruit to the same extent as occurred when the whole root system was exposed to extended drying.     

两种林木总DNA提取效果的比较

试验以刺槐（Ｒｏｂｉｎｉａｐｓｅｕｄｏａｃａｃｉａ）和华北落叶松（Ｌａｒｉｘｐｒｉｎｃｉｐｉｓ－ｒｕｐｐｒｅｃｈｔｉ）为ＤＮＡ提取材料,采用２种提取ＤＮＡ方法,紫外光检测林木ＤＮＡ提取纯度,并计算ＤＮＡ收率。实验结果表明,不同林木总ＤＮＡ提取的效果存在一定差异,从刺槐和落叶松两树种的生理特性和生长特点等方面对试验结果作了比较和分析。     

‘富士’苹果不套袋与套袋密度对树体光合特性的影响

为进一步探讨不套袋与套袋对苹果品质影响的机理,以8年生‘富士’苹果（‘天红2号’/‘M26’/八棱海棠）为试验材料,共设5个套袋密度处理（不套袋、套袋1/3的果实、套袋1/2的果实、套袋2/3的果实、套袋所有果实）,所用果袋为小林果袋（双层纸袋,内红外棕）,研究不同套袋密度对果实套袋前（6月19日）、套袋后2天（6月21日）、套袋中（8月22日和9月27日）、摘袋后2天（10月9日）和采收后1天（11月3日）苹果叶片光合特性的影响。结果表明,套袋不仅降低了苹果树冠层内的光照强度,而且显著降低了叶片的光合速率,而随着套袋密度的增加,苹果树冠层内的净光合速率显著降低,尤其是在8月和9月。5个处理的冠层光强、气孔导度、叶绿素含量、类胡萝卜素含量和叶片比重的变化与净光合速率的变化基本一致,说明果实套袋导致叶片光合性能下降。套袋苹果光合速率的降低是由气孔导度的降低引起的,这可能与光照强度降低有关;而在9月光合速率的降低还可能与高温弱光,套袋苹果叶片出现非气孔限制有关。     

环境因子对苹果树水势的影响及其日变化规律

在露地条件下对不同嫁接组合红星和金冠苹果树枝条、叶片及果实水势测试并应用灰色系统方法建立苹果树水势与环境因子日变化规律的GM (0 ,4)模型 ,结果表明 :苹果树各器官水势日变化均为早晨较高 ,午间或午后达最低值 ,傍晚回升到高于早晨的水平 ;温度、相对湿度和辐射照度是苹果树各器官水势日变化的主要影响因子 ,且不同嫁接组合苹果树各器官水势日变化的一次累加生成时间序列与温度、相对湿度及辐射照度日变化的一次累加生成时间序列呈线性函数关系     

退耕还林工程可持续发展问题研究

简要总结了我国自2002年全面启动退耕还林（草）工程以来所取得的成果．分析了还存在的工程规划不尽合理;没有建立起有效的产权制度;劣质种苗造林;未能适地适树等现象屡见不鲜;后续产业发展步履艰难等问题．为了巩固成果实现该工程的可持续发展,应采取保持政策的可持续性;政府进行宏观调控,刺激农民的参与意愿;征收生态环境补偿税;适地适树（草）提高工程质量等应对措施．     

Application of digital photogrammetry to measure distribution of tree postions

The application of digital photogrammetry to measure distribution of tree positions with stereo image couple is introduced in detail, and the procedure of stereo vision applied in forestry environment is explored. Nonlinear error in measure model is adopted in the camera calibration; the interactive correlation matching is used under constraint of epipolar line and edge of tree detected by Canny operator. Results prove that application of digital photogrammetry technology to measure distribution of tree positions can meet demand of precision in experimental conditions.     

杉木与七种阔叶树混交造林效果的初步研究

通过对7种优良乡土阔叶树种与杉木混交林的调查研究,结果表明:杉阔混交林提高了林分蓄积量,促进杉木和阔叶树种成林、成材。混交林中的杉木普遍比杉木纯林生长好,只有杉檫混交林例外。杉木和木兰科观光木、乳源木莲、壳斗科红锥、格氏栲以及樟科的檫树、樟树混交造林,有利于发展珍贵阔叶树种种群规模,具有推广应用前景。处理好种间关系是营造混交林成败的关键。     

四川珍贵树种资源发展潜力及战略

珍贵树种是经济社会发展特需的战略资源,发展珍贵树种资源具有十分重要的意义。文章介绍了四川珍贵树种资源发展现状,分析了珍贵树种资源发展潜力,提出了珍贵树种资源发展原则和发展战略。