共建南粤“海滩明珠”——记“同在蓝天下,共建红树林”大型环保公益活动

<正>灿烂的阳光下,一株株红树苗在碧蓝的海水中随风摇曳……尽管身枝柔弱,但红树苗的根已深深地植入底泥中,仿佛千万个卫士保护一方海滩。望着又长高了一截的红树苗,省环保基金会理事长陈坚无比欣慰,"再干三年、三十年,让更多的红树林更好地保护广东海岸线!"     

Elevated CO2 changes the moderate shade tolerance of yellow birch seedlings

To demonstrate the existence of light thresholds in plant growth and to examine the effects of elevated CO2 on the shade tolerance of a tree species, an experiment consisting of a completely randomized design for a total of 96 yellow birch (Betula alleghaniensis Britton) seedlings was conducted with 3 light levels (2.9%, 7.7%, 26.1% of full sunlight)×2 CO2 levels (350 and 700±10 ppm) with 4 replications in a phytotron. The study proved that thresholds exist and they vary in different plant organs. In ambient CO2, the thresholds were 13.3%, 18.7%, 15.0%, 15.2%, and 15.6% of full sunlight for stem, leaf, root, total plant biomass, and the averaged value, respectively. In 700 ppm CO2, the corresponding thresholds were 16.7%, 21.3%, 18.1%, 21.7% and 19.5% for stem, leaf, root, total plant biomass, and the averaged value, respectively. The lowest threshold in the stem is an indicator of the minimal light intensity for regular growth for seedlings of this species. Below this threshold, light-stressful growth occurs. The result of a paired t-test indicated that the thresholds in elevated CO2 were significantly higher than in ambient CO2. This suggests that yellow birch will lose its moderate shade tolerance, evolutionally becoming a shade-intolerant species, and that it may become more difficult to naturally regenerate in the future.     

应该这样做

正现今,人们的生活越来越富裕,环境却遭到了无尽的破坏。沙尘暴频发,荒漠化严重,污水四溢,空气污浊……这所有的现象都在提醒我们人类——地球虽然无言,但环境恶化带来的报复和惩罚正在上演。在各种灾难面前,我们不得不承认,在大自然面前,人类极其渺小。当我们在追究灾害原因时,往往忘记了这正是人类自己破坏环境所造成的恶果。所有的灾难都在     

环境教育不能搞成形象工程

正一间装潢华丽的环境教育展厅里,摆满了各类环保装置,配上多媒体,声光电,五光十色,令人眼花缭乱,好不热闹,博得了前来参观的领导们齐声叫好。终于,有参观者忍不住地问:孩子们呢?确实,参观者这才发现,如此高大上的环境教育展厅,却不见一个孩子的身影。偌大的展厅里连为参与活动的孩子们提供的桌椅都没有。显然,这间看上去高大上的环境教育展厅并不是给孩子们准备的,而是供领导前来参观的。说得再明确一些,这只是个形象工程,只有硬件没有灵魂。这样的情况不只发生在一所学校。一些学校为     

五颗鲜桃

<正>说起来,这都是40多年前的事了。有一年的春天,我和爷爷在院子里栽下了一棵桃树苗。常言说桃三杏四。一晃3年的时间很快过去了,在爷爷的精心侍弄下,这棵桃树已经长得快有2米高了。那年春天的时候,桃树果然就开了花。翠绿的树叶,粉红色的花朵,让人看了别提有多高兴了,而那朵朵艳丽的小花在我的眼里早已经幻化成一颗颗     

开展多彩活动,营造绿色氛围——北京市第九十六中学环境教育纪实

正北京市第九十六中学是一所初、高中兼具的完全中学。学校分为南北两个校区,办学条件良好,社区环境宜人。学校一贯坚持"以人为本,和谐发展"的办学思想和"追求一流,办有特色"的办学目标。学校享有极高的社会知名度和良好口碑,并因此被评为"北京市健康促进学校"、"北京市优美校园示范校"、"节约型示范校"。学校领导高度重视环境教育工作的开展,并以可持续发展思想为指导,使环境教育逐步成为学校工作中心的一部分。在学校全面的日常管     

树木——忠诚的环境卫士

记得每当电视里出现人们植树的画面,我总是不解地问爸爸这是为什么。爸爸摸着我的头耐心回答我:"多种一些小树苗,才可以防止水土流失,防止土壤沙化呀!"那时,我总是似懂非懂点点头。直到后来我有机会在旅途中碰见美景,我发现植树造林是那么的重要。     

土壤含水量对三种阔叶树苗气体交换及生物量分配的影响

在温室内用盆栽法研究了土壤含水量对茶条槭、山梨和山桃的气体交换及生物量分配的影响,设置4种土壤水分处理(土壤相对含水量75．0％、61．1％、46．4％和35．4％)．结果表明：随土壤含水量降低，3树种苗木净光合速率、蒸腾速率和气孔导度均下降，土壤含水量最低时，茶条槭苗木各生理指标降低幅度最大，山梨和山桃次之．茶条槭和山梨水分利用效率(WUE)随土壤含水量的减少呈降低趋势，山桃WUE呈升高趋势．水分胁迫下，3树种苗木根分配生物量显著增加．茶条槭在水分胁迫下，根冠比增加幅度最大，山梨次之，山桃最小．此外，茶条槭叶形态可塑性强，随土壤含水量降低，茶条槭单叶叶面积和总叶面积显著减小，叶厚度增加．山梨和山桃在水分胁迫下单叶叶面积及总叶面积无显著变化．综合3树种苗木在水分胁迫下的生理和形态指标及生物量分配的变化，茶条槭和山桃对水分胁迫的适应能力强于山梨．表4参31     

Changes of plasma membrane AtPase activity, membrane potential and transmembrane proton gradient in Kandelia candel and Avicennia marina seedlings with various salinities

The salt-secreting mangrove, Avicennia marina, and non-salt-secreting mangrove, Kande/ia candel were cultivated in sand with various salinities(0‰, 100‰, 20‰, 30‰, 40‰) for 60 d. Plasma membrane vesicles of highpurity in leaves and roots of A. marina and K. candel seedlings were obtained by two-phase partitioning. The function of the plasma membranes, the activity of ATPase, membrane potential and transmembrane proton gradient, at various salinities were investigated. The results showed that within a certain range of salinity( A. marina and roots of K. candel: 0-30‰; leaves of K. candel: 0-20‰), the activity of ATPase increased with increasing salinity, while high salinity (above 30‰ or 20‰) inhibited ATPase activity. In comparison with A. marina, K.candel appeared to be more sensitive to salinity. The dynamics of membrane potential and transmembrane proton gradient in leaves and roots of A. marina and K. candel seedlings were similar to that of ATPase. When treated directly by NaCl all the indexes were inhibited markedly: there was a little increase within 0-10‰( K. candel) or 0-20‰( A. marina) followed by sharp declining. It indicated that the structure and function of plasma membrane was damaged severely.     

五种亚热带树苗的生长与干物质分配格局对大气污染胁迫的响应

将乡土木本植物猫尾木Dolichandronecauda-felina、蒲桃Syzygiumjambos、野牡丹Melastomacandidum、翻白叶树Pterospermumheterophyllum以及鸭脚木Scheffleraoctophylla1年生袋装苗盆栽,置半庇荫环境下适应4周,之后按株数均等分成两组,分别放置在南海五星污染区和广州华南植物园清洁区进行试验。5个月后进行植物构形生长参数和干物质量的测定,以探讨这5种亚热带树苗对大气污染响应的差异。结果表明,①这5种树苗均能在清洁区和污染区都存活,但生长特征表现明显差别。②除翻白叶树基径有少许增大外,大气污染基本上都使植物基径生长减小;树高方面,除了蒲桃外,其余树种树高都有所降低,鸭脚木树高受到的影响最为严重。③翻白叶树与猫尾木单株侧枝数有少许增加,而蒲桃和鸭脚木单株侧枝数有大幅度地下降,分别减少为清洁区单株侧枝数的46.5%和65.1%,野牡丹单株侧枝数基本上没有受到影响。④在污染区生长的5个树种单株干物质总量除了翻白叶树有所增加外,其余4个树种单株干物质量均有不同程度地下降。⑤除了蒲桃保持不变外,污染区?生长4种植物冠根比(CRR)均有不同程度地增加。在污染区生长的植株叶质量比(LWR)和叶面积比(LAR)与清洁区相比存在差异,野牡丹和蒲桃叶质量比和叶面积比下降,而其余3种植物叶质量比和叶面积比上升。综合实验结果表明,5种植物幼苗中对大气污染抗性最强的是翻白叶树和蒲桃,抗性最弱的是鸭脚木。