马尾松和红锥叶片解剖和光合对穿透雨减少的响应

目的 探究8 a干旱胁迫条件下树木叶片光合生理特征与叶片解剖结构的响应及二者之间的关系。 方法 在南亚热带选取2种典型人工林（马尾松和红锥）设置林内穿透雨减少的模拟干旱实验,在穿透雨减少8 a后测定叶片气体交换参数、叶绿素荧光参数、叶片解剖特征以及叶片养分（N、P）含量。 结果 （1）穿透雨减少后,马尾松针叶上、下表皮、叶片厚度以及气孔密度显著增加,而红锥仅叶片上表皮厚度显著增加,海绵组织厚度显著降低。（2）马尾松和红锥的气体交换参数（净光合速率Pn、气孔导度Gs、蒸腾速率Tr）、叶绿素荧光参数（光系统Ⅱ最大光化学效率Fv/Fm、实际光化学效率 ΦPSII,表观电子传递速率ETR）以及叶氮、磷含量在穿透雨减少8 a后均未发生显著变化。（3）与马尾松相比,红锥受到的气孔限制（Ls）更大,水分利用效率（WUE）更高,尤其在干季更明显。 结论 马尾松和红锥应对干旱胁迫的策略存在差异,马尾松通过调节叶片解剖结构产生更具耐旱的针叶来应对干旱,红锥则更倾向通过调节气孔（Ls）、提高水分利用效率（WUE）来适应干旱。     

Cross-protection interactions in insect pests: Implications for pest management in a changing climate

Agricultural insect pests display an exceptional ability to adapt quickly to natural and anthropogenic stressors. Emerging evidence suggests that frequent and varied sources of stress play an important role in driving protective physiological responses; therefore, intensively managed agroecosystems combined with climatic shifts might be an ideal crucible for stress adaptation. Cross-protection, where responses to one stressor offers protection against another type of stressor, has been well documented in many insect species, yet the molecular and epigenetic underpinnings that drive overlapping protective responses in insect pests remain unclear. In this perspective, we discuss cross-protection mechanisms and provide an argument for its potential role in increasing tolerance to a wide range of natural and anthropogenic stressors in agricultural insect pests. By drawing from existing literature on single and multiple stressor studies, we outline the processes that facilitate cross-protective interactions, including epigenetic modifications, which are understudied in insect stress responses. Finally, we discuss the implications of cross-protection for insect pest management, focusing on the consequences of cross-protection between insecticides and elevated temperatures associated with climate change. Given the multiple ways that insect pests are intensively managed in agroecosystems, we suggest that examining the role of multiple stressors can be important in understanding the wide adaptability of agricultural insect pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Effects Of Thinning In a Water-Limited Holm Oak Forest

ABSTRACT

A natural holm oak forest was selectively thinned to test thinning as a tool to reduce tree mortality, increase productivity, and reverse the recent regression of the dominant species (Quercus ilex) induced by climate change. Thinning increased aboveground productivity and reduced stem mortality in this Mediterranean forest during four years just after thinning, contributing to the maintenance of forest functioning under changing climatic conditions. Q. ilex was the only species positively affected by the thinning: stem growth increased for all stem sizes, and mortality was significantly lower in thinned plots. On the contrary, mortality rates of Phillyrea latifolia and Arbutus unedo were not significantly lower. Stem growth increased for P. latifolia only in the smallest stem-size class. Our results highlight the suitability of selective thinning for improving the forest productivity and ensuring the conservation of Mediterranean coppices. Other benefits of selective thinning, such as a decrease in the risk of fire dispersion and an increase in the water supply for human populations, are also discussed.     

木荷人工林生长和木材基本密度

在福建省建瓯市选取1968—1997年间营造的多片木荷纯林和荷杉混交林,系统研究坡位、坡向等生境条件及与杉木混交对木荷人工林生长和木材基本密度的影响。结果表明:坡向和坡位对木荷生长和干形影响显著,但对木材基本密度影响较小。相对于阴坡和中坡,阳坡和下坡的木荷其树冠浓密、树高和冠幅生长量较大,干形略有改善,而阴坡因土壤水湿条件较好有利于木荷胸径的生长。与杉木按适当比例(如荷杉比为1∶3)进行混交,可明显促进木荷胸径、树高和冠幅的生长,并改善了干形。通过比较表明:木荷人工林分叉干发生的几率变化在22.50%～35.75%之间,且以0.5m以下的1叉干为主;对于地处阳坡和下坡的纯林及1∶3荷杉混交林,木荷分叉干发生几率相对较小;相对于坡向,坡位对分叉干形成的影响较大。研究发现:木荷人工林木材基本密度由髓心向树皮呈逐渐下降的趋势,15～20年生时开始明显减小,35～40年间达到最小值。木材基本密度从髓心向树皮下降的速度还随径生长量的增加而加快;年轮宽度呈先变宽后变窄的趋势,5～15年为木荷人工林径生长的速生期。据此应选择土壤水肥、光照条件较好的阳坡和下坡林地营造木荷人工林,同时提倡以适当比例混交经营,加强幼林的抹芽除萌...     

我国东北4种常见阔叶乔木物候对气候变化的响应

物候现象是指示气候及自然环境变化的重要指标(Peuelas et al.,2001;Moresette et al.,2009)。自然物候记录可以提供全球环境变化最直接和最有效的证据。已有研究结果表明,受全球气候变化影响,1952—2000年地中海地区(Peuelasetal.,2001)、1851—1994年匈牙利(Walkovszky,1998)、1936—     

论韶关地区道路绿化植物的科学选择与配置

韶关地区道路绿化树种大多数是从南部珠三角地区和北部湖南地区引进,可能存在所引进树种是否适应韶关气候的问题。因此,如何运用科学的方法选择与配置道路绿化植物和确定合适的种植位置就成为道路绿化工程的关键。     

川西南雷波县小海子孢粉组合特征与距今1.6万年以来古气候分析

根据该地层剖面不同时期泥炭地层的孢粉类型、数量的变化，将该不同年龄段剖面中出现的孢粉划分为六个孢粉组合带。利用不同时段孢粉类型及数量变化所反映的森林生态环境，重塑了不同时期的古气候特征。可概括为：从距今1．6万年晚更新世晚期，经冰后期晚更新世与早全新世分界，再经中全新世至晚全新世直到目前，经历了冰后期一个短暂转暖期一寒冷一温冷到温暖一温暖微干一温凉一温暖这一变化趋势。雷波小海子地处凉山州东部边缘，临近金沙江河谷，由于受黄茅埂高山阻隔和金沙江河谷干热气候影响，故自1．6万年以来气候变化波动较小，而与布拖县西溪河火烈湖2．2万年以来古气候有不同变化趋势。     

广州市帽峰山森林公园空气环境质量初报

本文对广州市帽峰山森林公园中的旅游气候指标——温湿指数和风效指数、空气离子浓度含量和空气洁净度等空气质量因子进行了测定,并运用有关方法进行评价。结果表明,该森林公园的旅游气候资源适合全年休闲、旅游;空气负离子含量高,有益于人体健康;空气环境质量达到国家A级,这为广州市森林生态网络建设和旅游资源开发利用奠定科学、翔实的基础数据。       

影响油橄榄产量与品质的气象因子分析

应用逐步回归分析的方法,研究了贝拉、佛奥、卡林3个油橄榄品种在四川主要种植点产量、含油率与日照、温度、湿度、降雨等23个气象因子的关系.结果表明:光、温、水指标综合影响油橄榄的产量和品质,影响油橄榄产量的气象因子分别为:年日照时数、日照百分率、4~10月日照时数、一月平均温度、极端最高温、极端最低温、0~10℃天数、日稳定通过10℃天数、无霜期天数、4~10月降雨量等.其中4~10月的日照时数是影响油橄榄出油率的关键因子.