广东鼎湖山斑岩钼矿区生物地球化学特征

本文对从钼矿区和对照区采集的岩石、土壤和植物样品的研究表明,矿区岩石与土壤中钼含量的相关系数为0.74,土壤与马尾松、桃金娘、鼠刺和芒箕叶片中钼含量的相关系数分别为0.9,0.87,0.98和0.99。在马尾松、桃金娘、鼠刺、芒箕和藤黄檀的叶片中,矿区相对于对照区,前者的最高钼含量是后者的18倍、53倍、12倍、46倍和35倍。钼含量高的土壤中生长的藤黄檀的细胞,在电子显微镜下其结构发生明显变化,主要表现为核膜界限消失,核仁解体,叶绿体结构受到破坏,细胞中有颗粒物存在。钼还会抑制植物叶片对镁的吸收。因此利用生物地球化学特征可以找出隐伏在植被下的矿床。     

The Impotence of Cumulative Effects Assessment in Canada: Ailments and Ideas for Redeployment

Cumulative effects assessment (CEA) in Canada is in dire straits. Despite a huge amount of talk and a flurry of developmental activity associated with CEA concepts, it has not lived up to its glowing promise of helping to achieve sustainability of diverse valued ecosystem components. This article aims to articulate that failure, to examine it in terms of six major problems with CEA, and to propose solutions. The six problem areas include (1) application of CEA in project-level environmental impact assessments (EIAs), (2) an EIA focus on project approval instead of environmental sustainability, (3) a general lack of understanding of ecologic impact thresholds, (4) separation of cumulative effects from project-specific impacts, (5) weak interpretations of cumulative effects by practitioners and analysts, and (6) inappropriate handling of potential future developments. We advocate improvements not only within the purview of project-specific EIAs, but also mainly in the domain of region-scale CEAs and regional environmental effects frameworks (or perhaps land use planning). Only then will the CEA begin to approach the promise of securing sustainability of valued ecosystem components.     

酸沉降对马尾松菌根共生蛋白及营养关系影响

研究模拟酸雨及不同Ｃａ／Ａｌ比对马尾松（Ｐｉｎｕｓｍ ａｓｓｏｎｉａｎａ Ｌａｍ ｂ．）菌根中真菌与植物共生及营养关系的影响,在分子水平上揭示污染对生物的作用和生物抗性机理．当ｐＨ２０ 的模拟酸雨与铝共同作用时,马尾松菌根中酸性磷酸酶、硝酸还原酶以及海藻糖酶和甘露醇脱氢酶活性明显下降,即ｐＨ２０ 的模拟酸雨及铝离子对马尾松幼苗根的磷、氮吸收以及两共生生物之间的营养物质交换过程产生了影响,且铝离子在ｐＨ值低的情况下毒性作用更强;而钙能有效地缓解铝的毒性⒚在本实验中当Ｃａ／Ａｌ比为１／１ 时,缓解能力最强;在接种外生菌根真菌彩色豆马勃（Ｐｉｓｏｌｉｔｈｕｓｔｉｎｃｔｏｒｉｕｓ）后,马尾松幼苗根部酶活性仍能保持一定水平,植物对模拟酸雨及铝毒的抗性增强．菌根形成初期,经等点聚焦电泳后分离出在植物及真菌纯培养中均不存在的共生蛋白,其等电点为４７０,经ｐＨ２０的模拟酸雨处理后该蛋白仍存在     

火炬松成熟合子胚培养直接体细胞胚胎发生和植株再生

以Hb、Ma和Mc3个基因型的火炬松成熟合子胚为外植体,建立了火炬松的离体培养直接体细胞胚胎发生植株再生体系实验结果表明,不同基因型火炬松之间的直接体细胞胚诱导频率有明显差异3个基因型中．Hb的成熟合子胚在附加1mg·L－12,4－D和4mg·L－1BA的DCR培养基上的直接体细胞胚诱导频率最高,达18％,扫描电镜观察表明,直接体细胞胚主要形成于成熟合子胚的子叶表而且胚轴较短,和母体组织仅保持胚根部位的联系组织细胞学切片结果表明,直接体细胞胚上胚根的发育落后于子叶,但是由直接体细胞胚发育形成的再生小苗有独立的维管组织,根部也较发达,并且整个小植株的维管系统和成熟合子胚上子叶的维管组织没有直接的联系.     

外生菌根真菌对油松幼苗根际土壤重金属赋存的影响

油松幼苗接种菌根盆栽试验表明,外生菌根真菌对油松根际土壤重金属铜、镉的赋存形态产生显著影响.与普通根际相比,菌根际土壤中交换态铜、镉含量显著下降,而有机结合态含量则显著增加.菌根际土壤重金属形态呈现出由疏松结合态向紧密结合态转化的趋势.接种菌根显著降低根际重金属的生物有效性,缓解重金属对寄主植物的毒害作用.     

水分胁迫下不同油松种源SOD、POD、MDA及可溶性蛋白比较研究

采用盆栽控水试验方法,设置正常水分（T1,田间持水量的70%~80%）、轻度胁迫（T2,田间持水量的50%~60%）和严重胁迫（T3,田间持水量的30%~40%）3个水分梯度,对6个油松Pinus tabulaeformis Carr.种源幼苗（陕西洛南LN,陕西桥山QO,山西灵空山LK,山西芦芽山LY,河北雾灵山WL和辽宁千山QN）的保护酶参数进行了分析。结果表明,在T3下,各种源的可溶性蛋白质含量、超氧化物歧化酶（SOD）活性、过氧化物酶（POD）活性和丙二醛（MDA）含量差异均极显著（P〈0.01）;LK种源的可溶性蛋白质含量显著高于其它种源,种源LK、WL和LN依靠提高可溶性蛋白质含量来调节细胞渗透势以抵抗干旱胁迫的能力较强;种源QN和QO的SOD活性达到最大,它们通过增加SOD活性来清除O2.-用以抵抗膜脂过氧化的能力较强。整个水分处理过程中,种源LN和LY的POD活性均较高,而QN的POD活性较低,LN和LY通过增加POD活性分解H2O2对细胞破坏的能力较强;各油松种源的膜脂质过氧化程度在T3下均有所降低。     

长白山红松和臭冷杉树轮密度变化特征及其气候响应

本研究建立了长白山红松和臭冷杉的全轮、早晚材密度年表,并分析了2个树种的树轮密度变化特征及其与平均气温、平均最高气温、平均最低气温和降水量的相关关系。结果表明：两树种树轮密度变化具有一致性。红松树轮密度对气候变化更加敏感,而臭冷杉树轮密度变化相对稳定。两树种树轮密度年表与平均气温和平均最低气温整体呈显著正相关,而与平均最高气温和降水量的相关性相对较弱。其中,生长季早期（4—5月）的平均最低气温可能是影响树轮密度变化的主要因素。响应面分析结果表明：随着生长季早期的平均最低气温上升,两树种早材密度与平均最低气温呈现先减弱后增强的响应趋势,而与生长季早期的降水呈现先增强后减弱的响应趋势。滑动相关分析显示：随着气候变暖,两树种树轮密度年表均对生长季晚期（9—10月）平均气温和生长季早晚期平均最低气温的正响应显著增强,而对生长季晚期平均最高气温的正相关减小,与降水的响应相对稳定。臭冷杉的树轮密度年表对上年12月平均最高气温和当年4月平均最低气温的响应出现显著的正负转换现象。     

Providing Habitat for Native Mammals through Understory Enhancement in Forestry Plantations

The Convention on Biological Diversity (CBD) expects forestry plantations to contribute to biodiversity conservation. A well‐developed understory in forestry plantations might serve as a surrogate habitat for native species and mitigate the negative effect of plantations on species richness. We experimentally tested this hypothesis by removing the understory in Monterey pine (Pinus radiata) plantations in central Chile and assessing changes in species richness and abundance of medium‐sized mammals. Frequency of occurrence of mammals, including kodkods (Leopardus guigna), culpeo foxes (Pseudalopex culpaeus), lesser grisons (Conepatus chinga), and Southern pudu deer (Pudu puda), was low in forest stands with little to no understory relative to stands with well‐developed undergrowth vegetation. After removing the understory, their frequency of occurrence decreased significantly, whereas in control stands, where understory was not removed, their frequency did not change. This result strongly supports the idea that facilitating the development of undergrowth vegetation may turn forestry stands into secondary habitats as opposed to their containing no habitat for native mammals. This forestry practice could contribute to conservation of biological diversity as it pertains to CBD targets. Proporcionando Hábitat para Mamíferos Nativos Mediante el Mejoramiento del Sotobosque en Plantaciones Forestales     

Acidity and conductivity of Pinus massoniana bark as indicators to atmospheric acid deposition in Guangdong, China

Introduction The ever-increasing development of human activities has given significant rise to atmospheric pollutants which have negative impacts on natural ecosystems, as for example the severe decrease of the forests (Soikkeli, 1981; Hirano and Hijii, 1…