广西森林生态旅游人才培养的思考

该文分析了广西森林生态旅游发展的现状与存在的问题，指出人才问题是影响广西森林生态旅游快速发展的主要问题之一。该文认为，广西森林生态旅游人才培养存在“对专业的重要性认识不足，专业方向不够明确；课程体系的设计缺乏操作性和针对性；人才培养层次不合理，培养规模小，数量上不能满足社会需求；偏重专业知识教育，缺乏学生综合能力和艰苦创业素养的培养；师资力量薄弱，教学质量难以保证；人才培养模式和教学方法落后，教学效果受到影响”等问题。该文提出，要结合广西森林生态旅游资源的特点，培养实用型人才；要重视意志品质教育，培养学生吃苦耐劳、艰苦创业的职业素养；要以就业为导向，使课程设置和教学安排与森林生态旅游景区的岗位要求相衔接；要与国际接轨，培养能接待境外游客特别是东盟国家生态旅游者的高素质人才；要采取各种措施，造就一支高素质的师资队伍。     

海南大学校园园林生态系统建设的探讨

笔者以亲身的实践和体会，对海南大学校园园林生态系统的建设进行了科学总结。指出校园园林生态系统建设要以生态学的原理和实践为依据，重点突出其绿化功能，其它美化、净化和气候宜人化等多种功能也要兼顾并充分发挥；比较详尽地分析了校园园林在生态系统生物种群组成的多样性；进而提出了优化校园园林生态系统结构的途径和措施。     

浅谈行道树对西安市生态环境的影响

本文根据西安市自然地理特点和工业布局，分析了行道树减污滞尘、减弱噪声、美化环境等改善西安生态环境质量的作用。同时分析了西安行道树栽种过程中所面临的问题，即树种单一，结构不合理；树木人为破坏严重，病虫害威胁等。根据这些问题，文章提出了一些治理措施，即改进树种，尽可能地实现树种多样化，速生种和慢生种间夹栽培；实现定期人为保护；采用一定的工程措施等。     

风景园林专业“土壤学＂课程教学改革的探讨

根据风景园林专业的性质和特点，针对目前“土壤学”课程中存在的教材与教师、课程内容与教学方式及考核等方面的问题，提出了改革的措施和建议。首先在改革的整体思路上要突出风景园林学的专业性和“土壤学，，课程的实用性；其次要根据专业性确定教学内容的重点和难点；要改变教学方式，采用启发式和讨论式等多种教学方式，着重培养学生的创新能力，以提高“土壤学”课程的教学质量。     

凉山州核桃产业发展及对策措施

本文在对凉山州核桃产业发展中存在的问题进行分析基础上，提出了应加强良种选育工作，确定适合当地的主栽品种；加强良种采穗圃建设，加快对低质低产核桃改造；改实生繁殖为嫁接繁殖，保证新发展核桃的整体品质；提高造林质量，加强管理，杜绝粗放经营等对策措施。     

瞄准高起点 争取新跨越——论广东园林城市建设中的现状问题与对策

本文透过广东园林城市的建设成就，分析了现状存在着的一些矛盾，如：城市总体规划与园林城市建设目标不配套，园林城市建设所需扩大的城市绿化用地来源难以保障，园林城市的建设任务不能仅仅由园林部门来“承包”等问题；概述了国内外有关“绿色城市”、“生态城市”的研究与建设动态；提出：面向新世纪，广东的园林城市建设应当要有新高度新思想、新措施。     

澳大利亚树木微量营养元素的研究方法

介绍了澳大利亚对树木微量营养元素的研究方法，包括：实验室和温室的条件；营养液的配制和纯化；试验材料（容器、沙和水）的选择；实验器皿的清洗；温室内管理措施；试验苗木的观察记载和养分分析；以及样品采集与处理方法等。     

固原市落叶松叶蜂发生特点及综合治理

结合林业生产实践，调查认为落叶松叶蜂在固原市具有广泛发生，危害集中且危害期短而严重；林分郁闭度在0．5～0．6时，危害程度最重；并且坡向不同，树种不同，危害程度也不同的发生特点。并在此基础上，分析了当前落叶松叶蜂的发生原因，提出要加强综合性营林措施，提高森林生态系统的调控能力，积极倡导实施多种防治技术措施，加强虫情监测及预测预报工作，并要加大检疫工作力度的综合治理措施。     

四川省退耕还林还草试点工作中有关问题的调查研究

对当前退耕还林还草试点工作普通存在的一些问题，如计划管理；退耕还林还草面积；退耕地界定和布局；退耕后还林的方向；种苗补助费；退还主体不一致；前期工作经费；林草管护形式与经费、退耕后不反弹以及承包耕地再分配和剩余劳动力转移等方面进行了分析探讨，并提出相应的解决对策和措施。     

泰兴市花卉产业发展的现状与措施

分析了泰兴市花卉业发展现状、总体特点及存在问题；提出了因地制宜、科学规划；制定优惠政策，加大花卉产业扶持力度；加大招商引资力度，培植龙头企业；搞好基地建设，培植特色产业；健全服务体系和建设信息网络体系等应对措施。     

预冻处理减少木材皱缩的研究

以大青杨为试验材料，研究了预冻处理对木材干燥皱缩特性的影响，分析了木材在冰冻处理过程中木材细胞腔和细胞壁尺寸的变化规律，理论上计算了细胞壁强度的增加范围。并通过电子显微镜分析冰冻过程对木材细胞壁结构的影响，进而深入探讨预冻处理减小木材皱缩的机理，为减少木材皱缩提供理论基础。结果表明：预冻处理可以减少大青杨木材的皱缩。     

2013年冬季海口林场常绿植物冻害调查分析

针对2013年冬季昆明遭遇了低温雨雪天气的影响,对昆明市海口林场露天苗圃地栽培的常绿植物冻害进行了调查。结果显示：所调查的43种植物中,16种植物有不同程度的受冻,占37．2％;冻害级别3级以上有8种,分别是缅桂、清香木、小叶女贞、尖叶木樨榄、小叶榕、马蹄荷、三角梅、鹅掌柴,占18．6％;部分树种幼树和成年大树冻害程度一样,部分树种随着年龄增加,冻害程度降低。根据这次冻害的发生情况,提出了在今后苗木生产过程中,要针对性地对易受冻害的苗木进行保护管理,推广应用抗冻能力强的植物,改良抗冻能力,加大应用乡土绿化植物的力度。     

Comparison of G6PDH Activity and LT50 Between P.tomentosa and P.suaveolens During Freezing Acclimation

The differences of glucose-6P dehydrogenase(G6PDH) activity and freezing resistance induced by freezing acclima-tion between cuttings of freezing-sensitive P.tomentosa and freezing-resistant P.suaveolens were compared for exploring the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation.After 5d of freezing acclimation at -3℃ ,the LT50 of P.tomentosa has deereased from -6.2℃ incontrol cuttings to -14.3℃ in freezing acclimated ones,and the increase of LT50 of P.tomentosa has decreased from -6.2℃ in control cutting to -14.3℃ in freezing acclimated ones,and the increase of G6PDH activity was observed in freezing acclimated cuttings as compared with control ones.Whereas,when P.suaveolens was freezing acclimated at -20℃ for 5d,the LT50 has decreased from -27.1℃ in control cuttings to -43.5℃ in freezing acclimated ones,and the activity of G6PDH increased considerably.In addition,the increase of LT50 and the decrease of G6PDH activity resulting from 2d of deacclimation at 25℃ were found in two kinds of freezing acclimated cuttings.It is concluded that the increase in the activity of G6PDH may associate with the inherited freezing resistance of species and the enhancemen of freezing resistance of cuttings,and may play an important role in the antifreeze process under freezing temperature,which would provide the basis for the study on the molecular mechanism of freezing resistance in P.suaveolens and the cloning of gene associated with freezing resistance.     

钙-钙调素对中东杨扦插苗的诱导抗冻作用

以零下低温锻炼和结合效应剂（CaCl2、钙离子螯合剂EGTA、钙离子通道阻断剂LaCl3或钙调素拮抗剂CPE）处理的低温锻炼下的中东扬扦插苗为试材，对其体内丙二醛（MDA）及钙调素CaM含量，SOD、POD及线粒体Ca^2-＋ATPase活性分别进行测定。结果表明，低温锻炼不仅在一定程度下提高了幼苗CaM含量，提高了SOD、POD和Ca^2＋-ATPase活性，降低了MDA含量；而且减少了低温胁迫所引起的SOD、POD，Ca^2＋＋ATPase和CaM含量的下降程度以及MDA的增加幅度。在低温锻炼的同时。用CaCl2处理能加强低温锻炼的效果，但这种效应可被EGTA、LaCl3或CPZ处理抑制。经低温锻炼后，幼苗中的CaM含量的增加有助于SOD、POD和线粒体Ca^2＋-ATPase活性的提高，进而对幼苗抗冻性的提高有明显的促进作用。     

The role of antioxidant system in freezing acclimation-induced freezing resistance of Populus suaveolens cuttings

We investigated the changes in the contents of H2O2, malonaldehyde (MDA) and endogenous antioxidants, the activities of protective enzymes and some critical enzymes involved in the ascorbate-glutathione (ASA-GSH) cycle as well as freezing resistance (expressed as LT50) and correlations mentioned above, in detail using Populus suaveolens cuttings. The purpose was to explore the physiological mechanism of the enhancement of freezing resistance induced by freezing acclimation at –20°C, and to elucidate the physiological mechanisms by which trees adapt to freezing. The results showed that freezing acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), monodehydroascorbate reductase (MDAR), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR). And it increased the contents of reduced ascorbate (ASA), reduced glutathione (GSH), dehydroascorbate (DHA) and oxidized glutathione (GSSG). However, H2O2 and MDA contents and LT50 of cuttings were decreased. LT50 in cuttings was found to be closely correlated to the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, H2O2, MDA, ASA, GSH, DHA and GSSG during freezing acclimation. This suggested that the enhancement of freezing resistance of cuttings induced by freezing acclimation may relate to the distinct increase for the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, ASA, GSH, DHA, and GSSG. In addition, the observed levels of APX, DHAR, MDAR, GR, ASA, DHA, GSH and GSSG were higher than those of SOD, POD and CAT during freezing acclimation. It indicated that a higher capacity of the ASA-GSH cycle is required for H2O2 detoxification, and growth and development of cuttings. Based on the obtained results, it can be concluded that the ASA-GSH cycle plays an important role in enhancement of freezing resistance of P. suaveolens cuttings during freezing acclimation.     

The use of field and artificial freezing studies to assess frost tolerance in natural populations of Pinus oocarpa

The susceptibility of Pinus oocarpa to freezing temperatures limits the commercial deployment of the highly productive Pinus patula × P. oocarpa hybrid in South Africa. Identifying P. oocarpa germplasm with increased frost tolerance is important. Twenty-three P. oocarpa provenances, originating from Mexico, Honduras, Guatemala and Nicaragua, were therefore assessed for their tolerance to freezing conditions by analysing field survival after frost events, subjecting needles to freezing temperatures and assessing damage using the electrolyte leakage test, and exposing young plants to freezing temperatures in a semi-controlled environment and scoring tissue damage based on a visual assessment. The performance of many of the provenances represented in the field and artificial freezing studies were similar and there was a strong correlation between provenance ranking in the whole plant freezing and electrolyte leakage test. We therefore support the use of these techniques as a means to assess cold tolerance in P. oocarpa at the provenance level. Provenances from north-western Mexico demonstrated more frost tolerance than those from southern Mexico. Provenances representing Honduras and Guatemala appear to be highly susceptible to frost.     

Characterization and Role of Glucose-6-phosphate Dehydrogenase of Populus suaveolens in Induction of Freezing Resistance

Glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) was purified from the leaves of 8-week-old Populus suaveolens cuttings. The enzyme activity in the absence and presence of reduced dithiothreitol (DTTred) was determined. The results show that the G6PDH activity is not inactivated by pre-incubation with DTTred, indicating that the purified enzyme probably presented in cytosol of P suaveolens. The catalytic characteristics and kinetic parameters of cytosolic G6PDH purified from P.suaveolens cuttings were also studied. The results show that G6PDH is characterized by Km value of 360/amol.L^-1 for G6P and 16μmol.L^-1 for NADP, a pH range of 7.3-8.9, and the maximum activity around pH 8.2. The enzyme activity is inhibited by various metabolites such as NADPH, NADH, GTP, UTP, ATP, AMP, ADP, CoA, acetyl CoA, fructose-6-phosphate (F6P), erythrose-4-phosphate (E4P), ribose-5-phosphate (R5P) and 3-phosphoglycerate (3-PG) (all at 1 mmol‘L i except for NADPH and NADH)to different extents. NADPH is the most effective inhibitor of enzyme activity, with an inhibition of 72.0%. The addition of metal ions such as MgC12, CaC12 and KC1 (all 1.0 mmol.L^-1) to the standard reaction mixture has no remarkable influence on the cytosolic G6PDH activity. However, CdCl2 (1.0 mmol.L-1) causes high inhibitory effect on the enzyme activity. To explore the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation, the changes in the cytosolic G6PDH activity and freezing resistance (expressed as LTs0) of P. suaveolens cuttings during freezing acclimation at -20℃ were investigated. The results reveal that freezing acclimation decreases LTs0 of cuttings, and increases the activity of cytosolic G6PDH compared with control ones,while 2 d of de-acclimation at 25 ~C result in a decrease in cytosolic G6PDH activity, and caused an increase in LT50. Furthermore,the change in cytosolic G6PDH activity is found to be closely correlated to the degree of freezing resistance of cuttings during freezing acclimation. It is suggested that cytosolic G6PDH may be involved in the induction of freezing resistance of cuttings.     

低温冻害对宜川花椒生长的影响

花椒为宜川县干旱山区乡镇农民家庭经济收入的重要来源。但是,花椒低温冻害对其发展有很大影响。本文对宜川县在不同立地条件、不同品种、树龄和不同环境下的花椒冻害进行调查研究。结果表明,在宜川县栽植花椒,要选择背风向阳的山坡地、选择抗寒品种和加强管理可以减免低温冻害发生。     

核桃、花椒低温冻害调查与分析

本文对宝鸡市花椒的低温冻害情况作了全面调查,并提出了相应的应对措施。     

Chlorophyll fluorescence as an indicator of frost hardiness in white spruce seedlings from different latitudes

This study examined the utility of variable chlorophyll fluorescence (F_var) to detect freezing damage in white spruce seedlings of four seedlots. Logistic regression analysis done for freezing tests in September showed that visible needle damage from freezing could be estimated by the F_var attributes F_o/I_ABS(r²=0.94), F_p(r²=0.98), F_v/F_m (r²=0.99), and F₁(r²=0.86). The regression curves indicated that for all four fluorescence attributes, inflection points occurred between 10 and 20% visible needle damage. The lack of a relationship between fluorescence attributes and visible seedling needle damage in October through December is because the minimum temperature (–18 and –24°C respectively) applied was insufficient to cause needle damage. Freezing-induced changes to F_var attributes can be detected which also result in photosynthetic rate decreases when no visible needle damage, and even electrolyte conductivity changes are evident. F_var attribute differences due to freezing can be resolved to the seedlot level. The Fvar curve feature manifested 5 seconds after dark-adapted seedlings have been exposed to light (F_5s) will estimate (r²=0.76) photosynthetic rate after freezing.