Acclimation abilities of three tropical rainforest seedlings to an increase in light intensity

Current practices in many nurseries involve the germination of tropical rainforest seedlings in shaded conditions and transferral, at a later date, to environments with greater light intensities. Determination of the ability of these seedlings to acclimate to increased light intensities will allow seedling stock to be processed with maximum efficiency within the nursery. The acclimation abilities of three species, Agyrodendron actinophyllum, Cardwellia sublimis, and Flindersia brayleyana, commonly found in north Queensland's rainforests were investigated in this study. These particular species are highly valued for their cabinet timber qualities and are being reared in nurseries for use in reforestation trials and programs in north Queensland. Seedlings were initially raised in greenhouse conditions under two layers of shade cloth (16% of full sunlight) and then transferred into full sunlight at three different ages (3 weeks, 10 weeks, 14 weeks). Upon transfer, organ ratios and the direction of dry matter distribution was determined for each species and age group. Approximately 3 months after the seedlings were transferred, the acclimation ability of each species and age group was then determined. Dry matter distribution was found to change with age, irrespective of light environment. Individuals within a species with larger root systems and thicker or more dense leaves had a greater acclimation ability than those with smaller root systems and thinner or less dense leaves. Furthermore, individuals within a species whose dry matter distribution upon transfer was directed towards developing a large root system, and a small photosynthetic area and mass, had a greater acclimation ability than those whose dry matter distribution was directed away from such morphologies. Awareness of these relationships allows a better understanding of seedling response to gap formation in natural forests, and also allows plant nursery operators to make a more informed decision about when to move seedlings to environments with a higher light intensity.     

杉木扁长蝽若虫空间分布型的研究

本文采用聚集度指标检验法、回归分析法研究了杉木扁长蝽若虫的空间分布型。结果表明：在不同林地、不同虫口密度情况下，均呈聚集分布。若虫的聚集与栖息生境有直接关系。     

甲苯侧链催化氯化产物分布的研究

研究了催化氯化的产物分布，试验了有关条件对产物分布的影响。结果表明：氯化程度是产物分布的主要影响因素；温度的提高，有利于苄叉二氯和苄川三氯的生成；铁离子、低温及水会导致环上的氯化；水引起水解的发生。     

我国南方部分地区实蝇记述及2种中国新记录

1980～1988年,曾用地中海实蝇、瓜实蝇和桔小实蝇(Trimedlure,Cuelure 和 Methy eugonol)性引诱剂,和野外采果相结合的办法,进行了实蝇的调查,所采集的标本,已鉴定出16种,其名称是;桔小实蝇、芒果实蝇、番石榴实蝇、辣椒实蝇、颜带实蝇、鳄梨实蝇、瓜实蝇、南瓜实蝇、颜黑纹实蝇、具条实蝇、拟具条实蝇、腹眼实蝇、二态实蝇、蜜柑大实蝇、桔大实蝇和黑肩光顶实蝇.内鳄梨实蝇和腹眼实蝇2种为中国新记录.在这次调查中,未发现地中海实蝇(Ceratitiscapitata Wied.)。     

Importance of the River Teviot to Atlantic salmon, Salmo salar, rod catches in the River Tweed, Scotland

Abstract  The body mass distributions and variations in abundance of the spring and autumn catches of Atlantic salmon, Salmo salar L., were compared between fisheries above and below the confluence of the rivers Tweed and Teviot, Scotland. Significant differences between the distributions were found over three periods, one in spring and two in autumn, when salmon catches were high. Correlations were found between abundance trends for periods when distributions were similar or dissimilar. Abundance of salmon returning to the River Teviot was proportional to the main river. However, its population structure differed when abundances were high, suggesting different survival strategies. It appears that changes in the numbers returning to the river were resultant of changes in the marine rather than freshwater environment.     

杉木林杆材阶段能量积累和分配的研究

目前森林生态系统生产力的研究 ,多以干物质量作为指标 ,这对深入了解生态系统的功能 ,生态效益都有一定的局限性。必须把生物量与能量结合起来 ,因为生物量和能流的研究 ,是人工林生态系统结构和功能的研究中最主要的一环 ,是研究物质生产、物质循环和能量流动的基础。关于森林各组织器官的热值和能量的研究 ,国内外许多学者做过这方面的工作。刘世荣等 (1990 )研究了落叶松 (Larixgmelinii)林群落能量积累、分配、固定和转化的规律 ;陶金川等 (1990 )探讨了银鹊树 (Tapisciasinensis)群落的生物量和能量的现存量 ;张文其等 (1995 )对鹤山…     

Physiological Analysis of Yield Variation in Mungbean (Vigna radiata [Roxb.] Wilczek)

Two mungbean varieties, Guj-1 and PIMS-1 differing in their productivity potential, were examined to investigate their photosynthetic system at various stages of growth in relation to yield with two different dates of sowing. Vertical leaves were found to be beneficial. On the other hand, excessive leaf area during the later stages of growth may be detrimental to yield. Lower LAD at seedling stage and overall high NAR values may be reflected in higher grain yield. NAR declined as season progressed and this, in turn, may be related with increase in LAI. The grain yield was considerably more at the first date of sowing as compared to second date of sowing, the effect was being more pronounced in var. PIMS-1 . Various environmental factors recorded at two different dates of sowing and at various stages of growth indicated that these factors may have influenced the yield potential at two different dates of sowing.     

关于φ—变换的一点注记

Frazier和Jawerth系统地研究了分布空间的离散变换,即变换,本文讨论了f~aq,[f_p~[aq]]上的投影算子,得到了‖{sup_〔Q_b〕〔f〕}_Q‖■_p~[aq]与‖{sup_[Q_b]}Q‖■_p_[aq]的等价性以及‖f‖F_p~aq[b]与‖f‖F_p~[aq]的等价性.     

水稻中系8541与中系8240光合特性的比较研究

本文通过光合作用参数的测定,详细的研究了中系8541和8240两种不同产量水平的水稻品种的光合特性.论述了在含等量叶绿素的条件下,中系8541和中系8240之间在对光谱的吸收、叶片的光合作用量子转化效率,叶绿体的PSⅡ(光系统Ⅱ)潜在活性(Fv/F_0)和原初光能转化效率(Fv/Fm等的主要区别.实验结果说明,上述各光合作用参数中系8541都优于中系8240.不仅如此.在Mg~(2+)作用下,Fv/Fo和Fv/Fm比值的提高以及Mg~(2+)对两个光系统激发能分配的调节能力中系8541也强于中系8240.     

人工培植羊体羊黄的研究

本试验以外科手术方法在北京农户所养绵羊胆囊内放人异物网核和注入致黄菌(SEBF8,50亿/ml),诱发羊黄,均获成功.其间,对术前术后血清胆红质、胆固醇、谷草转氨酶和GROS反应等项进行测定.结果表明:上述各项指标在术后8天内与术前比,均有降低,差异显著,但以后逐渐恢复正常.而体重、临床表现,以及饲养指标本出现异常.预示着,人工培植羊体羊黄可行.同时,本试验还为进一步提高人工培植羊黄的产黄量,提供了参考数据.