不同环境条件下籼型杂交稻株高的发育遗传研究

采用数量性状的加性 显性发育遗传模型分析了按NCⅡ交配设计的两套籼型三系杂交水稻在两种环境条件下株高的发育遗传规律。供试材料和环境均会影响水稻株高表现,且环境对株高的影响随发育进程的推进不断减小。在不同发育阶段,水稻株高主要受加性和显性效应基因共同控制,但影响程度会随供试材料的改变而有所不同;基因型与环境互作效应会对株高产生一定影响;控制株高的遗传效应在各发育时期均有新的表现,且加性效应的表达比显性效应的表达更为活跃;条件环境互作效应亦会对株高发育遗传产生一定影响,前期影响尤其大;水稻株高的群体平均优势总体上随发育进程的推进而逐渐增加,至成熟期达到最大;群体超亲优势的变化规律因供试材料的不同而略微出现一些差异,但均在后期趋于稳定,且均为正值。在多数发育时期,水稻株高条件群体平均优势达到正向显著或极显著水平,而条件群体超亲优势达到负向显著或极显著水平,即群体平均优势和群体超亲优势在各时期均有新的表现,但其表现的大小和方向均有所不同。     

不同种质沙棘在干旱条件下营养生长适应性的研究

在干旱条件下,不同种质沙棘的营养生长适应性差异较大,中国沙棘和杂交沙棘的营养生长适应性显著强于俄罗斯良种沙棘,后者各品种间的营养生长适应性有差异;干旱缺水是影响不同种质沙棘的主导因素,年降水量少于400mm时,无灌溉或地下潜水补给的沙棘,营养生长适应性将大受影响,造林建园时应给予充分重视。     

秦岭冷杉幼苗适应性的研究

通过对秦岭冷杉不同海拔、光照、苗床类型、覆土深度等条件下的野外播种试验,分析了不同条件下种子萌发、幼苗存活和幼苗生长率的差异,揭示了秦岭冷杉种子及幼苗在天然环境下的适应性.天然生境下秦岭冷杉的平均出苗率只有17.7％,不及实验室发芽率(36％)的一半.海拔、光照、苗床类型、埋藏深度对秦岭冷杉的种子萌发、幼苗存活和幼苗生长率都有不同程度的影响.生产上秦岭冷杉的复壮一定要遵循适地适树的原则.     

毛黄肉楠光强适应性的初步研究

用100％、81％、41％、28％和5％五种光照处理毛黄肉楠苗木,研究结果表明：（1）5％光照处理下的苗木全部死亡,而另外4个处理苗木存活率为100％,长势较好;（2）毛黄肉楠的光饱和点较低（250—300umol·m^-2·s^-1）,且随遮荫的加强而降低;（3）苗高、地径、叶面积、总生物量、叶绿素含量、表观光舍量子速率的变化规律皆以遮荫处理下（81％、41％、28％）为高。综合光合特性、生理特性和自然分布特点表明,毛黄肉楠为中性树种,在半荫蔽条件下生长良好,表现出对弱光环境的适应。     

Relationship between species richness and biomass on environmental gradient in natural forest communities on Mt. Xiaolongshan,northwest China

We analyzed the relationship between species richness and biomass in natural forest communities at two similar sites on Mt. Xiaolongshan, northwest China. At both sites, a wide range of tree layer biomass levels was available by local biomass estimation models. In order to identify underlying mechanism of the species richness-biomass relationship, we included different water resource levels and number of individuals in each plot in our analysis. We sampled 15 and 20 plots （20 m ×20 m）, respectively, at both two sites. These plots were sampled equally on the sunny slope and the shady slope. Species richness, number of individuals of each species and diameter at breast height （DBH） as a substitute of biomass of tree layer were recorded in each sample. At one site, the relationship between species richness and biomass was significant on the sunny slope, and this relationship disappeared on the shady slope due to more environmental factors. The relations between species richness and number of individuals and between number of individuals and biomass paralleled the species richness-biomass relation on both slopes. The difference in number of individuals-biomass relationships on the sunny slope and the shady slope revealed ＂interspecific competitive exclusion＂ even though the species richness-biomass relationships were not hump-shaped. At the other site, species richness was not related to biomass or to number of individuals. Our study demonstrated the importance of environmental stress and succession of community in the understanding of species diversity-productivity patterns.     

3个南非耐旱引进树种在云南省的生长适应性初步研究

引进南非干热逆境地区的Acacia karoo、Acacia nilotica、Albizia adiolutica 3个含羞草科(MIMOSACEAE)树种在云南进行生长适应性研究结果表明,在各试验点生长保存情况各自不同.在3个试验点,Acacia karoo生长都优于其他2个树种,Albizia adiolutica生长都较差.此外,3个树种在3个代表云南省不同气候的试验点的生长与试验点关键气候因子的相关性分析表明,3个树种都对炎热干燥的气候有明显的适应性,而不适宜种植在降雨丰富和湿度较大的地区.     

近50年兰州城市空间扩展模拟及其未来预测

利用高分辨率航片、Landsat TM影像和土地利用现状图,建立兰州市1949-2005年城市扩展G IS空间数据库,应用改进的SLEUTH模型,重建兰州市1949-2005年城市空间扩展过程,并情景模拟未来扩展趋势。采用两种不同历史年份跨度情景、校准SLEUTH模型。研究表明:该模型客观地重建了兰州市1949-2005年城市动态扩展过程;两种不同情景预测仍将继续沿河谷扩散发展,在城市增长方式与空间分布上既相似又有显著差异:情景1预测城市扩展趋势快于情景2预测,更接近于现实城市扩展趋势;情景2预测对城市扩展控制较严格,更趋向于可持续发展。建议近期内加强兰州建成区内部土地利用空间结构优化与空间置换,进而加快城市职能的空间置换,同时为未来发展预留一定的土地储备和发展空间。     

旅游发展中利益相关者环境意识水平分析

环境意识作为一种新的独立意识形态,能够规范社区与社会的生活方式和经济活动方式.因此,旅游发展的生态安全状态取决于直接利益相关者的环境意识水平以及他们之间的相互利益协调关系,主要包括:旅游管理部门、旅游者、旅游企业和当地社区。文中根据环境意识结构,设计了旅游环境意识调查问卷,其主要的指标体系包括:旅游环境知识水平、旅游环境态度、旅游环境评价和旅游环境行为四个方面。并设计了环境意识总体评价模型,以此来计算旅游发展中旅游环境意识水平的综合得分。经过分析得知,旅游管理部门的环境意识水平最高,其次是社区居民,再次是旅游企业,最后是旅游者,而且总体水平都不高。所以,在旅游发展中必须提高各利益相关者的旅游环境意识水平,推动他们自觉参与保护旅游生态环境安全的行动中来。     

Multivariate analysis of toxicological and environmental properties of soil nematicides

BACKGROUND: In intensive agriculture, the use of pesticides and soil fumigants is necessary to produce economically viable crops worldwide. However, this practice may involve undesirable effects on human health and the environment. In 1995, methyl bromide was restricted by the Montreal Protocol because of possible ozone depletion. The objective of this study was to compare intrinsic environmental and toxicological properties of 11 active substances with nematicidal properties, some of them recognized as methyl bromide alternatives. RESULTS: Four groups of active substances were discriminated by a series of principal component analyses (PCAs): (a) high toxicity to non-target fauna, humans and animals and medium persistence in the environment (cadusafos, ethoprophos and fenamiphos); (b) high toxicity to humans, animals and non-target fauna and high persistence (carbofuran and fosthiazate); (c) low toxicity to non-target fauna, humans and animals and low persistence (carbosulfan, benfuracarb and oxamyl); (d) low toxicity to humans, animals and non-target fauna and medium persistence in the environment (1,3-dichloropropene, chloropicrin and methyl bromide). CONCLUSION: Evaluating the multiple aspects of toxicological and environmental properties of active substances through PCA is proposed as a helpful tool for initially comparing the complex toxicological behaviour of active substances as plant protection products.     

热研4号王草的适应性及其在福建的推广应用

通过适应性研究,发现热研4号王草适合在福建地区生长。该草表现为产量高、生长快、营养品质高,适口性好等优点,表现出良好的生态适应性和经济价值,适宜福建地区在种草养畜、种草养鱼、养殖场污染治理、荒山生态恢复等方面推广应用。