长白落叶松插穗的内源激素水平及其与扦插生根的关系

长白落叶松 (Larixolgensis)扦插繁殖的试验结果表明 ,嫩枝扦插效果好于硬枝扦插 ,并且母树年龄是影响其扦插生根的重要因子。母树年龄为 2年生时 ,生根率达 95 %以上。本文在此试验的基础上 ,对嫩枝和硬枝插穗中内源植物激素水平进行了测定。结果发现嫩枝插穗中IAA、CTKs的含量要高于硬枝插穗中IAA、CTKs的含量 ,并且随母树年龄的增加而降低 ;相反 ,嫩枝插穗中ABA含量要低于硬枝插穗中ABA的含量 ,并且随着母树年龄的增加而增加。实验结果表明 :IAA、ABA的含量和扦插生根有密切关系。IAA促进生根 ,ABA抑制生根。IAA/ABA比值可以用来衡量长白落叶松的生根能力     

秋季牧草根系中营养含量和酶活性变化和及其抗寒性研究

 本文研究了秋季高寒山区垂穗披碱草(Clinelymus nutans)根系中碳水化合物、蛋白质含量和过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性变化及与牧草抗寒性的关系。结果表明,秋季随着气温的下降,牧草根系中碳水化合物和可溶性蛋白质含量增加,CAT和SOD活性增强。其中火烧地的全期平均碳水化合物、可溶性蛋白质含量和CAT、SOD活性明显高于未火烧地,总增幅度也较大。秋季牧草根系中碳水化合物和可溶性蛋白质含量增加是多年生牧草贮藏能量物质安全越冬和翌年再生芽萌动的能量需要,而CAT和SOD活性的增强可阻止低温下细胞中氧自由基的积累,使植物生物膜系统免受伤害,是决定植物抗寒性的另一重要因子。火烧地牧草春季萌动早,长势强,产量高,秋季其根系中碳水化合物和可溶性蛋白质含量高及CAT和SOD活性强是重要原因。     

THE OCCURRENCE AND ADAPTIVE SIGNIFICANCE OF NOCTURNAL HABITS IN WATERFOWL

This paper reviews the occurrence of nocturnal activity, particularly foraging, in wildfowl (Anseriformes) and shorebirds (Charadrii), and discusses its significance. Many duck species are mainly active at night while others regularly feed during both the day and night. Some ducks and geese are normally day feeders and occasionally forage during darkness. In a few duck species, courtship also has been observed at night. Most shorebirds forage both by day and night, in temperate and in tropical latitudes. Some are mainly crepuscular and nocturnal feeders and also display at dusk and at night. Some species may use their daytime territory at night. A few shorebird species, including some visual peckers and long-billed tactile probers, use the same foraging method to detect and capture food by night as by day. However, some long-billed species that forage visually during daytime modify their feeding techniques and rely completely or partly on tactile means for detecting prey at night. Large eyes seem an advantage to plovers and other sight feeders for night feeding. Numerous touch-sensitive corpuscles in the bill of ducks and many scolopacid species favour tactile feeding. Some ducks, geese and shorebirds may especially use moonlit nights for feeding though, in a few species, moonlight seems to have no effect. The possible role of bioluminescence is also discussed. Nocturnal activity may occur for two reasons. The night may be preferred because foraging is more profitable or safest from predators. Alternatively, birds may be forced to forage at night because they fail to collect all their food requirements during the day. The evidence for both hypotheses is reviewed. Nocturnal activity does appear to allow wildfowl, and perhaps shorebirds, to avoid diurnal predators (including man). Shorebirds, and some ducks also seem to take advantage of prey that are more abundant and/or accessible at night. The main evidence for the supplementary feeding hypothesis comes from studies of seasonal variations in the occurrence of nocturnal feeding, about which rather little is known at present. The increasing availability of modern night-viewing equipment may help to fill this gap. There are two important implications arising from the widespread occurrence of nocturnal activity in wildfowl. Most knowledge on time and energy budgets is based on daytime studies, and so may need to be revised. Wintering dabbling ducks and shorebirds, at least in some regions, may use different habitats by day and by night. If confirmed, there would be a need to preserve some wintering habitats which, although little used by ducks and shorebirds during the day, may be intensively used at night.     

THE MORPHOLOGY OF THE OSPHRADIUM IN RELATION TO FEEDING HABITS IN MESO- AND NEOGASTROPODS

The morphology of the osphradium in nine species of meso- andneogastropods was examined using scanning electron microscopy.Herbivores and detritivores (Littorina, Aporrhais) have simpleosphradia consisting of long ridges, covered in ciliary tufts,and flanked on either side by bands of densely ciliated epithelium.Another herbivore Rhinoclavis has the central ridge dividedinto lobes. In carnivorous and predatory species (Polinices,Cypraea, Nucella, Nassarius, and Conus) the osphradium is shorter,larger and divided bi- or triserially, into leaflets. Conusstri-atus which feeds upon the most mobile and least predictableprey (fish) has the largest and most elaborate osphradium, withthe leaflets divided into digitiform processes. The sedentary,ciliary-feeding, Crepidula is anomalous in having an osphradiumdivided into leaflets, although these are vestigial along oneside.     

THE EFFECTS OF KINETIN AND NAPHTHALENEACETIC ACID ON IN VITRO SHOOT MULTIPLICATION AND ROOTING IN THE FISHTAIL FERN

This study is concerned with the determination of the shoot and root inducing effects of kinetin (K) and naphthaleneacetic acid (NAA) on shoots ofthe fishtail fern (Nephrolepisfalcata formafurcans) in sterile tissue culture. The data shows that K is the major factor involved in maximal shoot production. The NAA is not essential. Specific concentrations ofNAA must be present with specific concentrations of K for maximal root production. At the same time, the data also demonstrate that shoots on media containing no NAA but with K concentrations of 5 × 10⁻⁷ and 10⁻⁶ M produced as many roots as with any other NAA concentration. The data can be used as a guide to rapid commercial propagation of fishtail fern, and demonstrate that media available commercially for Boston fern multiplication will induce maximal shoot production in fishtail fern.     

热带雨林片断化对榕小蜂和榕树物种的影响

榕树是热带雨林生态系统中的一类关键物种。榕树必须依靠榕小传数值和获得有性繁殖;而榕小蜂的幼虫又必须依靠榕树瘿花为食才能生长生长和繁衍后代,因此二者间有着密切的共生关系。研究表明：在西双版纳热带雨林榕小蜂科有３属１７种分布。热带十麻片断化使榕小蜂和榕树的种类呈明显下降趋势;片断热带雨林面积的大小二对二得的物种娄和个体数有明显的影响。     

OBSERVATIONS ON THE FOOD HABITS OF TAME WARTHOG AND ANTELOPE IN UGANDA

Monthly observations were made of the food habits of tame warthog, reedbuck and kob over a period of a year. Measurements were taken of the shoulder height and size of mouth of the animals at different stages of their growth. Whilst a few species of grass were regularly preferred, the majority showed fluctuations in their preference. Some consistent seasonal differences were apparent. Most herbs were avoided. Large differences in food habits occurred between warthog and antelope; however, there was some overlap during the rains when food was abundant and at the height of the dry season when it was scarce. Some differences were apparent between kob and reedbuck and between individual warthog and reedbuck. Intraspecific differences, however, were less noticeable than interspecific differences. The height of the animal and the size of its mouth were important in determining the portion of the sward available for food and the degree of selection possible within the available food supply.     

THE FOOD AND FEEDING HABITS OF GOLDENEYE BUCEPHALA CLANGULA IN GREAT BRITAIN

The food and feeding habits of Goldeneye Bucephala clangula are described, based on the analyses of 51 stomach contents and a brief review of the literature. The type of food taken depends on the type of habitat being used, the availability and size of the food items and on the methods of feeding—though animal material largely predominates.
In estuarine and coastal areas, small crustaceans and in particular Carcinus maenas figured highly in the diet, with some molluscs and small fish. In two brackish-water feeding birds, seeds formed the bulk of the food, some caddis-fly larvae also being taken. In freshwater feeding birds insects predominated, particularly Trichoptera larvae, chironomid larvae and the adults of Corixa spp. Some crustaceans ( Asellus, Gammarus ) and small molluscs were taken and occasionally small fish. A small amount of plant material was taken in the form of seeds, mainly Potamogeton spp.
The relation between Goldeneye and fishing interests is briefly discussed and it is concluded that fish normally form a small part of the diet and it is unlikely that any serious depredation of fish stocks is common.     

REPRODUCTIVE BIOLOGY OF A TROPICAL PALM SWAMP COMMUNITY IN THE VENEZUELAN LLANOS

The reproductive biology of a tropical palm swamp community, called morichal in the Venezuelan Central Llanos, was studied. Of the 128 woody and herbaceous species of plants recorded, 99 (77.34%) were hermaphrodites, 25 (19.53%) were monoecious, and four (3.13%) were dioecious. The morichal is characterized by a low number of species with obligate cross-fertilization. The frequencies of species with different breeding systems in a subsample of 26 species showed that eight (30.77%) were self-incompatible, 14 (53.85%) were self-compatible, and four (15.38%) were agamospermous. Ten of 14 self-compatible species were autogamous. Regardless of the self-incompatibility level estimated, seed and fruit set were greater in self-fertilized flowers than in hand-pollinated flowers in three of the nine self-incompatible species. These results are related to the facts that: 1) the relative isolation of the plant population limits the gene flow among similar communities and enforces the intrapopulation pollen flow; 2) the overlapping flowering patterns and infrequent and unspecialized pollinators may be enforcing self-compatibility and agamospermy; 3) self-compatibility is the rule among short-lived species in the morichal; and 4) three out of four agamospermous species are of the Melastomataceae family.     

AGAMOSPERMY AND THE LOSS OF DISTYLY IN ERYTHROXYLUM UNDULATUM (ERYTHROXYLACEAE) FROM NORTHERN VENEZUELA

Erythroxylum undulatum is a gametophytic apomict that produces about 15% seed set independently of pollination. Embryo sac formation is aposporous, and the plants are largely pollen-sterile, which may be a result of polyploidy and hybrid origin. It appears to be derived from a distylous ancestor, as all other known species of Erythroxylum are distylous or secondarily dioecious, and all examined individuals of E. undulatum correspond to the normal long–styled morph. This is the first clearly documented case of agamospermy derived from distyly.     

柞树体内营养元素的垂直分布

本文对柞树的皮、干、根及树冠各层的营养元素,按照不同的高度和层次进行了分析,阐明了这些营养元素在柞树各器官中的垂直分布规律,同时提出了有些营养元素在树皮、树干中的分布存在一个“过渡区”,为进一步研究柞树林的养分动态机理提供了依据。