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Pollination Ecology of Pedicularis punctata Decne. (Scrophulariaceae) in the Kashmir Himalaya 总被引:2,自引:0,他引:2
Abstract The pollination ecology of Pedicularis punctata was studied in the Pir Panjal Range of the Kashmir Himalaya in the summer of 1989. Its nectarless, rostrate, long-tubed flower was found to be pollinated exclusively by Bombus foragers vibrating pollen while the stigma contacted pollen in the pollinator's cervical crevice. Workers of Bombus tunicatus and B. flavothoracicus comprised 95% of its pollinators. Pollen-foraging fidelity of its pollinators was greatest where diversity of Bombus -pollinated plant species in three plant communities was least. Foragers on other plants carried virtually no Pedicularis pollen. P. punctata is a mid-season blooming species similar in its pollination syndrome to comparable species in other geographic regions. The enigmatic function of its long, nectarless corolla tube, even more exaggerated in other Asiatic species, requires further investigation. 相似文献
5.
Georg Miehe 《Plant Ecology》1988,79(1-2):21-32
The vegetation of Mt Everest is described by means of the dominant plant formations and characteristic features of biotopes. Climatic data givenin connection with weather observations show evidence that the extreme asymmetry of the altitudinal vegetation belt on the south and north slope is induced by heavy rainfall on the south slope and the desiccating effect of the Himalaya föhn in the valleys of the north slope. Biotope shift from hypsozonal distribution on the south slope to extrazonal distribution on the north slope is described, the patterns of the actual timber line are discussed in order to reconstruct the natural upper forest limit, and regressive plant successions during the last 400 years of man's impact are summarized. The dominant vegetation pattern of the alpine belt is compared with that in the European Alps. On the arid north slope alpine steppe communities occur up to 5 500 m. The highest altitudinal vegetation belt and the highest plant communities at 5 960 m are dominated by periglacial processes. The highest records of flowering plants (6 100/6 200 m) and lichens (7 400 m) are discussed in light of the present knowledge on high-altitude vegetation ecology. 相似文献
6.
小竹鼠在我国仅分布于云南西部热带亚热带地区。主要生活于山坡稀树灌丛、阔叶林、橡胶园及居民点附近。在盈江县分布于海拔300-950米地带。取食、休息、繁殖主要在洞道内。洞系由洞口、取食道、趋避道、窝及“厕所”组成。食物主要有棕叶芦、芦竹及三叶橡胶等18种,尤喜食橡胶树主根,因而对橡胶树危害很大。13号标本中雌7雄6。在盈江每胎2-3只,以2只为多。成年小竹鼠过独居生活,雌雄各有自己的洞系。 相似文献
7.
谷蠹生态学特性的研究 总被引:3,自引:0,他引:3
谷蠹Rhyzoperthadominica(F.)生态学特性的试验结果表明,温度、湿度、粮食含水量对其各发育历期影响非常显著;食物影响不显著。 相似文献
8.
Dr. P. K. Khosla O. P. Toky R. P. Bisht S. Hamidullah 《Trees - Structure and Function》1995,10(2):108-113
In the mid-western Himalaya (altitude 1350 m, rainfall 1100 mm), multipurpose trees found as escapees in agricultural fields or naturally growing in the forests, play an important role in providing fuel, fooder and small timber to the farmers. Shoot elogation, and tree architecture of 4 year old trees of Grewia optiva, Robinia pseudoacacia and Celtis australis (early successionals), and Quercus leucotrichophora, Q. glauca and Ilex odorata (late successionals), were analyzed. All the late successional species showed a proleptic type of bud and branch production, while the early successional trees made growth through syllepsis. The shoot elongation differed significantly (P <0.05) with the crown position, and ranged from 11 to 30 cm in different species. Early successional species tended to maintain a comparatively narrow crown and showed a significantly (P <0.05) higher ramification ratio, and multilayered canopy. The late successionals, in contrast, showed a wide crown with monolayered canopy, adapted to the weak light intensity. There was only one flush of leaves in Q. leucotrichophora and Q. glauca while in the rest of the species there were two distinct flush periods. The results are important for the management of agroforestry trees. 相似文献
9.
R. K. Gupta 《Plant Ecology》1978,37(2):111-118
Summary Effects of human influences on the vegetation of the Western Himalaya have been reviewed. Impacts of forest management practices, over-grazing, surface mining, defence and development operations, and road building activities, are severe in the region. This has created an alarming situation for soil and water conservation. Increased soil loss and runoff pose a threat to various reservoirs built for various uses and have increased hazards of erosion and floods in the Indus and Ganga basin regions.Nomenclature follows Hooker (1872–1897) and Gupta (1968). 相似文献
10.
We investigated the relationship between eggsize variation and (a) egg hatching success, (b) chick survival to fledging and
recruitment, and (c) adult female survival, over 12 years in the lesser snow goose (Anser caerulescens caerulescens). By comparing the means and variances of egg size for successful and unsuccessful eggs, our aim was to assess the relative
fitness of eggs of different sizes and to determine the type of selection operating on egg size in this species. As both egg
size and reproductive success vary with age in the lesser snow goose we controlled for the effects of female age. Egg-size
variation is very marked in this population, varying by up to 52% for eggs hatching successfully. However, there was no relationship
between egg size and post-hatching survival of goslings to fledging or recruitment, either within or between broods, pooling
across years. Egg size varied significantly between successful and unsuccessful clutches in only 2 of 33 individual year comparisons.
First-laid eggs surviving to onset of incubation, and eggs hatching successfully, were on average larger than unsuccessful
eggs, but this was probably due to the confounding effects of female age-specific and sequence-specific egg survival. Variance
of egg size differed significantly between successful and unsuccessful eggs in only 3 of 24, and 0 of 21, individual year
comparisons for pre- and post-hatching survival respectively. We therefore found little evidence for a relationship between
egg-size variation and offspring fitness, or for strong directional, normalising or diversifying selection operating on egg
size, in the lesser snow goose. In addition, there was only weak support for the hypothesis that egg-size variation is maintained
by temporal variation in selection pressure (sensu Ankney and Bisset 1973). It is likely that egg-size variation represents the pleiotropic expression of alleles affecting
more general physiological or metabolic processes. While this does not rule out the existence of alleles with more direct
effects on egg size we suggest that their contribution to heritable egg size is small. 相似文献