辐照柑桔和板栗害虫的研究

本文对检疫害虫柑桔大实蝇和栗象的辐照处理了研究。     

Seasonal shoot and needle growth of loblolly pine responds to thinning, fertilization, and crown position

The impacts of thinning, fertilization and crown position on seasonal growth of current-year shoots and foliage were studied in a 13-year-old loblolly pine (Pinus taeda L.) plantation in the sixth post-treatment year (1994). Length of new flushes, and their needle length, leaf area, and oven-dry weight were measured in the upper and lower crown from March through November. Total shoot length was the cumulative length of all flushes on a given shoot and total leaf area per shoot was the sum of leaf areas of the flushes.

By the end of June, first-flush foliage reached 70% of the November needle length (14.3 cm) and 65% of the final leaf area (15.0 cm²). Cumulative shoot length of first- and second-flush shoots achieved 95% of the annual length (30.3 cm), whereas total leaf area per shoot was 55% of the final value (75.3 dm²). Fertilization consistently stimulated fascicle needle length, dry weight, and leaf area in the upper crown. Mean leaf area of upper-crown shoots was increased by 64% six years after fertilization. A significant thinning effect was found to decrease mean leaf area per shoot in the crown. For most of the growing season, the thinned-fertilized trees produced substantially more leaf area per shoot throughout the crown than the thinned-nonfertilized trees. These thinned-fertilized trees also had greater needle length and dry weight, longer first flush shoots, and more leaf area per flush than trees in the thinned-nonfertilized plots. Needle length and leaf area of first flush shoots between April and July were linearly related to previous-month canopy air temperature (T_a). Total shoot length strongly depended on vertical light gradient (PPFD) within the canopy, whereas shoot leaf area was a function of both PPFD and T_a. Thus, trees produced larger and heavier fascicles, more and longer flush shoots, and more leaf area per shoot in the upper crown than the lower crown. We conclude that thinning, fertilization, and crown position regulate annual leaf area production of current-year shoots largely by affecting the expansion of first flush shoots and their foliage during the first half of the growing season.     

南方地区杨树胶合板材定向培育技术的研究

随着工业技术的发展,工业生产对木材和其它林产品提出了更高、更新的要求,要求各类用材实行定向培育,这是世界人工林发展出现的战略变化１）。杨树具有生长快、成材早、产量高和易于更新的特点,为最适的短轮伐期工业用材林经营树种（方升佐等,１９９３）。所谓定向培育,是指按最终用途所确定的对木材原料的要求,采用集约经营等科学管理措施,生产出种类、质量、规格都大致相同,价格具竞争力的大批木材原料。本文简要总结了南方地区杨树胶合板材定向培育技术中关于无性系选择、立地控制、密度控制、栽植材料选择及优化栽培模式等研究…     

浸渍纸饰面层压木质地板质量现状分析

本文通过「近百个浸渍纸饰面层压木质地板的检测数据,分析了目前国内市场上该产品的２和发展,为标准制订提供限依据。     

用瞬时转速法估算压缩压力的探讨

在分析了反拖工况下曲轴受各力矩的变化规律曲柄转角与瞬时转速之间的相位关系的基础对用瞬时转速法估算柴油机压缩压力进行了探讨,给出了一种用曲轴的瞬时转速数据估算各缸压力的实用方法,在一台四缸直喷式柴油机上的试验结果表明,用该方法由飞轮的瞬时转速检测气缸的最高压缩压力,其标准误差不超过０．０３ＭＰａ,所提出的方法可用于柴油机的监测诊断系统中。     

斗轮堆取料机变幅试验装置的动态特性

根据ＤＱ１０００／１５００．４５型斗轮堆取料机变幅设计制造了变幅试验装置,建立了三维梁元有限元模型,借助于有发元分析软件,利用子空间迭代法对模型进行了求解,得到其大有频率及相应的振型,对试验装置的动态特性进行了试验研究,测试结果验证了有限元建模和计算方法的正确性。     

小麦抗赤霉病突变体的选育及RAPD分子验证

利用辐射诱变,组织培养和细胞筛选相结合的方法选育出了抗赤霉病突变体９２ｋ８０９该突变体不仅抗赤霉病能力强,且抗性稳定,同时具有优良的农艺性状,比原亲本增产４．９％,经ＲＡＰＤ技术检测,所用的１２８个引物中有１个引物（ＯＰＹ１５）在抗病变体９２ｋ８０９和赤霉病抗原苏麦３号中得到了相同的扩增产物,初步认为该片段与赤霉病的抗性有关。     

植物修复技术与农业生物环境工程

介绍了植物修复技术的概念、内涵、研究方法等,探讨了植物修复技术的优缺点和控制因素,指出农业生物环境工程手段的引进将有可能大幅度提高植物修复污染土壤的相对效率。     

与黄原胶生物合成相关的"1.9" kb EcoRI DNA片段的序列测定分析

对Ｘａｎｔｈｏｍｏｎａｓｃａｍｐｅｓｔｒｉｓｐｖ．ｃａｍｐｅｓｔｒｉｓ（下称Ｘｃｃ）８００４菌株染色体基因组中９．４ｋｂＨｉｎｄⅢＤＮＡ的“１．９”ｋｂＥｃｏＲＩ酶切片段的测序分析结果表明,该ＥｃｏＲＩＤＮＡ片段的实际长度为１．８８ｋｂ。在核苷酸水平上与Ｘｃｃ的ｇｕｍ基因有９８％的一致性;这一ＥｃｏＲＩ片段上有两个有意义的ＯＲＦ：ＯＲＦ１和ＯＲＦ２。ＯＲＦ１是一个不完整的ＯＲＦ;在氨基酸水平上,ＯＲＦ１和ＯＲＦ２的推断性编码产物蛋白分别与ｇｕｍＡ基因编码的ＧｕｍＡ及ｇｕｍＢ基因编码的ＧｕｍＢ蛋白有１００％的一致性。因此在１．８８ｋｂＥｃｏＲＩ片段上存在一完整的ｇｕｍＢ基因。     

水稻黄单胞菌水稻变种的rpfA基因的定位和次级克隆

水稻黄单胞菌水稻变种产生两种顺乌头酸酶（ＸｏｏＡｃａｎＡ和ＸｏｏＡｃａｎＢ）,编码ＸｏｏｃａｎＡ的ｒｐｆＡ基因已被克隆在重组质粒ｐＧＸＮ３０００中。本工作通过转座子Ｔｎ５Ｂ２０诱变ｐＧＸＮ３０００,鉴定了ｒｐｆＡ基因的位置及其转录方向,并进一步将含有完整ｒｐｆＡ基因的４．８ｋｂＡｓｐ７１８ＥｃｏＲⅠ片段次级克隆到了多用途载体质粒ｐＩＪ３２００。