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71.
The post-initiation growth of 64 anthers (1.1–17.4 mm long) in Lilium longiflorum Thumb. was examined by time-lapse marking experiments in combination with serial sections and the scanning electron microscope. Each anther was characterized by spatial and temporal variation in growth rate. Larger anthers had two, and occasionally three, series of peaks and troughs in local growth rate. Regions of negative growth rate were frequently encountered. When observed over several days, the growth maxima and minima were found to move basipetally as a waveform down the length of the anther. The wavelength was longer in taller anthers; amplitude and frequency were variable, and anthers of the same size were not always synchronous. Distribution patterns of cell division (and elongation, once division has ceased) recapitulate the growth data. Anther growth is a non-steady system, therefore, with growth centers constantly shifting. Implications for future studies in organ growth patterns are discussed.Abbreviation SEM
scanning electron microscope 相似文献
72.
It appears that the tapetum is universally present in land plants, even though it is sometimes difficult to recognize, because it serves mostly as a tissue for meiocyte/spore nutrition. In addition to this main function, the tapetum has other functions, namely the production of the locular fluid, the production and release of callase, the conveying of P.A.S. positive material towards the loculus, the formation of exine precursors, viscin threads and orbicules (= Ubisch bodies), the production of sporophytic proteins and enzymes, and of pollenkitt/tryphine. Not all these functions are present in all land plants:Embryophyta. Two main tapetal types are usually distinguished in theSpermatophyta: the secretory or parietal type and the amoeboid or periplasmodial type; in lower groups, however, other types may be recognized, with greater or lesser differences. A hypothetical phylogenesis of the tapetum is proposed on the basis of its morphological appearance and of the nutritional relations with meiocytes/spores. The evolutionary trends of the tapeta tend towards a more and more intimate and increasingly greater contact with the spores/pollen grains. Three evolutionary trends can be recognized: 1) an intrusion of the tapetal cells between the spores, 2) a loss of tapetal cell walls, and 3) increasing nutrition through direct contact in narrow anthers. 相似文献
73.
74.
The effects of floral morphology on rates of pollen removal and deposition by different pollinators in generalist plant species are not well known. We studied pollination dynamics in wild radish, Raphanus raphanistrum, a plant visited by four groups of pollinators: honey bees, small native bees, butterflies, and syrphyd flies. The effects of anther position and other factors on pollen removal during single visits by all four pollinator taxa were measured. Flowers with high anther exsertion (i.e., anthers placed higher above the opening of the corolla tube) tended to have the highest numbers of pollen grains removed, but this effect was strongest for honey bees and butterflies. For all pollinator taxa, pollen removal increased with the number of pollen grains available on a flower and whowed a positive, decelerating relationship with the duration of the visit. The effects of stigma position and other factors on pollen deposition during single visits by honey bees and butterflies were also studied. The nectar-feeding butterflies had a higher pollination efficiency (percentage of pollen grains removed from anthers that were subsequently deposited on a stigma) than the nectar- and pollen-feeding honey bees. Flowers with intermediate stigma exsertion had the highest numbers of pollen grains deposited on their stigmas by butterflies, but stigma exsertion had no effect on deposition by honey bees. For both butterflies and honey bees, pollen deposition on the recipient flower increased with the amount of pollen removed from the donor flower, and there was a positive, decelerating relationship between deposition and time spent at the flower; these results are analogous to those for pollen removal. The effects of anther and stigma exsertion on pollen removal and denosition did not fit predictions based on patterns of floral correlations, but results for morphology, pollen availability, time spent per visit, and pollinator efficiency are in broad agreement with previous studies, suggesting the possible emergence of some general rules of pollen transfer. 相似文献
75.
用卡宝品红染色法检查格列那什二倍体葡萄(Vitis vinifera var. Cre nache)花药再生植株的染色体, 并用UNICHRO软件对其数目及长度进行了测量。结果表明,这些花药植株根尖中染色体组型为2n=3x=57的细胞平均占观察细胞总数的86.5%,来自不同花药的再生殖株均为三倍体。讨论了这些植株的可能来源。
Abstrart:The chromosome number in the root tip of triploid plants regenerated from anther culture of diploid Vitis vinifera var.Grenache were examined with Carbolfuchsin staining method and the length of chromosomes were measured with UNICHRO package.The results show that average pecentage of cells which have a karyotype for 2n=3x=57 in root tip of pollen plants were 86.5% in the total number of cells observed,the plants regenerated from different anthers are triploid.Their possible origin is discussed. 相似文献
76.
Using three diploid tuber-bearing Solanum clones as anther donors, experiments were conducted on the effect of high temperature shock and elevated incubation temperature during anther culture on androgenic embryo production. Five incubation treatments were tested on two clones and three treatments were repeated in a second experiment on one of the same clones and an additional one. In the first experiment, temperature treatment, genotype, date of culture initiation, and their interactions were all significant sources of variation. A treatment combining a high temperature shock (35 °C for 12 h) with elevated incubation temperature (30/20 °C) yielded 11 times as many embryos (44 per flask) as the control 20 °C (4 per flask). By conducting several replications per day of bud collection, the significant variation due to experimental dates was separated from experimental error to provide a more sensitive test of treatment effects. Temperature shock (35 °C 12h) during anther culture did not appear to influence the subsequent conversion rate of androgenic embryos. 相似文献
77.
遗传学、优生学与伦理学试探A 总被引:3,自引:0,他引:3
遗传学、优生学与伦理学试探邱仁宗(中国社会科学院哲学研究所,北京100732)APreliminaryApproachtoGenetics,EugenicsandEthicsQiuRenzong(InstituteofPhilosophy,Chine... 相似文献
78.
癸培养基的研制及在小麦花药培养中的应用研究 总被引:6,自引:0,他引:6
在多年的小麦(Triticum aestivum L.)花药培养育种及对多种培养基应用研究的基础上,从调整培养基的大量元素和微量元素入手,建立了癸培养基。经过L_(16)(4~5)正交实验,筛选出NH_4N0_3、KNQ_3、MgSO_4、MnSO_4在培养基中较优的配比。在培养基对比实验中,癸培养基的愈伤组织平均诱导率分别比C_(17)、W_(14)、N_6培养基提高了30.31%、50.60%和57.96%,且对不同的杂交组合都能表现出优越性。在癸培养基中附加0.9mg/L REA(rare eaxth addition,稀土元素附加剂),可使小麦花药愈伤组织诱导率提高54.25%~64.07%,并对愈伤组织的生长有促进作用。 相似文献
79.
Michael Hesse 《Plant Systematics and Evolution》1980,136(1-2):41-46
The anther tapetum of the gymnospermGnetum gnemon produces no lipid osmiophilous droplets as pollenkitt forerunners. Thus—in contrast to entomophilous and anemophilous angiosperms—no pollenkitt is produced at all. From lack of pollenkitt in other gymnosperms, it appears to be restricted to angiosperms. This can be considered as new and additional proof for the hypothesis that the angiosperms are one coherent phylogenetic group, and that the development of pollenkitt in their ancestors was one of the main prerequisites for the adaptive switch to entomophily. 相似文献
80.
In recent years liquid medium has been shown to be better than agar-gelled medium for production of haploids by anther culture. However, on addition of charcoal to agar medium the anther response in Datura innoxia Mill, increases dramatically and is better than in liquid medium. For anthers with pollen at the premitotic stage, the best result was observed with 1% charcoal in Difco agar and 1.5% in Normal agar. The effect is possibly due to adsorption of substances inhibitory to androgenesis and emanating from anthers, as well as to substances present in the nutrient medium and agar. 相似文献