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101.
To ensure that the initiation of flowering occurs at the correct time of year, plants need to integrate a diverse range of
external and internal signals. In Arabidopsis, the photoperiodic flowering pathway is controlled by a set of regulators that include CONSTANS (CO). In addition, Arabidopsis plants also have a family of genes with homologies to CO known as CO-LIKE (COL) about which relatively little is known. In this paper, we describe the regulation and interactions of a novel member of
the family, COL5. The expression of COL5 is under circadian and diurnal regulation, but COL5 itself does not appear to affect circadian rhythms. COL5, like CO, is regulated by GIGANTEA. Furthermore, COL5 is expressed in the vascular tissue. Using COL5 over-expressing lines we show that, under short days, constitutive expression of COL5 affects flowering time and the expression of the floral integrator genes, FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CO 1. Constitutive expression of COL5 partially suppresses the late flowering phenotype of the co-mutant plants. However, plants with loss of COL5 function do not show altered flowering. Taken together, our results suggest that COL5 has COL activity, but may either not
have a role in regulating flowering in wild-type plants or may act redundantly with other flowering regulators.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
102.
Monika Kozłowska Magdalena Rybus-Zając Jerzy Stachowiak Beata Janowska 《Acta Physiologiae Plantarum》2007,29(1):27-32
The effect of gibberellic acid (GA3) on the carbohydrate accumulation in relation to vegetative growth of Zantedeschia ‘Black Magic’ plants undergoing transition to flowering was investigated. In response to GA treatment the carbohydrate level
increased independently of earlier stimulation of shoot emergence. Under vegetative growth stage the content of reducing sugars
of leaf blades was 2.5-fold higher than in control plants, and suggests the stimulation of photosynthetic activity. The changes
observed during the flowering, in principle noted in petiole tissues, support the GA-effect on assimilate transport to the
sink organs. Moreover, the high level of non-structural carbohydrates in petiole tissues, in particular reducing sugars, can
be an effect of photosynthetic activity of these organs and/or essential for osmoregulation and high turgor pressure. The
results indicate that apart from the influence on the shoot emergence, the GAs may stimulate the photosynthetic activity from
the beginning of shoot growth and are thus responsible for the enhancement of callas flower yield. 相似文献
103.
有花植物触敏柱头的闭合行为一直是传粉生态学和进化生物学研究的热点问题之一。植物花的多裂片柱头在传粉者接触后迅速闭合的现象主要存在于玄参目的一些类群中。早在上个世纪初,植物学家就对花的柱头闭合现象进行过初步的研究,认为柱头闭合主要是由于花粉在柱头上萌发时吸收水分导致柱头细胞膨压降低而引起的;并对柱头闭合的适应性提出了一些假说。近年来,许多学者研究证实柱头闭合能促进花粉萌发及花粉管伸长,或减少花粉散出与柱头接受花粉间的相互干扰,提高传粉者访问过程中花粉的散播量,并且柱头的状态会直接影响传粉者的取食行为。到目前为止,对柱头闭合的机制及其避免自交的假说还存在许多争议。关于触敏柱头的闭合行为,尤其是其适应机制及其生态学意义还有待更加系统和深入的研究。本文概述了触敏柱头的研究进展,并对研究中尚存在的一些问题进行了讨论。 相似文献
104.
Archana Joshi-Saha Thirumalai Gopalakrishna 《Molecular breeding : new strategies in plant improvement》2007,20(4):389-399
This is the first report on genetic studies and molecular tagging of a gene regulating flowering time in the stem nodulating
legume crop Sesbania rostrata (Bremek. & Obrem.). An F2 segregating population was developed from a cross between Trombay Sesbania rostrata-1 (TSR-1, a radiation induced late flowering
mutant) and S. rostrata. A phenotypic segregation ratio of 3 (normal flowering):1 (late flowering) in the F2 generation indicated that the late flowering is governed as a monogenic recessive trait. A genotypic ratio of 1:2:1 in the
F2 generation, determined from phenotypic segregation patterns in 73 F3 families, confirmed the monogenic inheritance of the late flowering trait. Inter Simple Sequence Repeat (ISSR) and Amplified
Fragment Length Polymorphism (AFLP) marker techniques were evaluated for their applicability as genetic marker systems in
this green manure crop. Using the F2 segregating population, an ISSR marker (UBC 8811000) tightly linked to the trait was identified. Two linked AFLP markers GCTG500 and CCAT350 were also identified. They were found to be at a distance of 1.4 ± 0.034 cM and 8.0 ± 0.047 cM flanking the flowering locus
respectively. The ISSR marker UBC 8811000 was converted into a Sequence Characterized Amplified Region (SCAR) marker. The single recessive mutation regulating the
late flowering trait and the availability of tightly linked, flanking markers will help in identification and isolation of
the gene controlling the flowering time trait. 相似文献
105.
光周期对穗花狐尾藻生长、开花与种子形成的影响 总被引:1,自引:0,他引:1
通过人工补光和遮光处理,初步研究了光周期对狐尾藻生长和开花的影响。研究发现:8h短日照条件不利于狐尾藻的生长和花序形成,导致狐尾藻不能正常开花和结实;与自然日照长度(平均日照14h)条件下相比,16h长光照条件可以增加植株的高度和分枝数,形成更大的生物量;但24h全光照条件对生长有抑制作用。长光照条件下,狐尾藻花序形成时间和开花时间均比自然条件下延迟,形成花序的数目也显著较自然条件下的少,但长光照条件下形成的种子比自然条件下形成的种子具有更高的萌发率。 相似文献
106.
Adriana Szmidt-Jaworska Krzysztof Jaworski Jan Kopcewicz 《Journal of Plant Growth Regulation》2006,25(3):233-244
Cyclic adenosine diphosphate ribose (cADPR) is a potent endogenous calcium-mobilizing agent synthesized from NAD+ by ADP-ribosyl cyclases described for several animal cells. Pharmacological studies suggest that cADPR is an endogenous modulator
of Ca2+-induced Ca2+ release channels. There is also information about the sub-micromolar concentration of cADPR in plant cells. Whether cADPR
can act as a Ca2+-mobilizing intracellular messenger in plant tissue is an unresolved question. Despite the obvious importance of monitoring
cADPR cellular levels under various physiological conditions in plants, its measurement has been technically difficult and
requires specialized reagents. In the present study a widely applicable sensitivity assay for cADPR is described. We show
that Pharbitis nil tissue from cotyledons contains a certain cADPR level. To explain the possible roles of this second messenger in photoperiodic
flower induction, some physiological experiments were also performed. The exogenous applications of cADPR to Pharbitis nil plants, which were exposed to a 12-h-long subinductive night, significantly increased flowering response. Nevertheless 8-Br-cADPR
inhibited flowering when these compounds were applied during a 16-h-long inductive night. The effect of ruthenium red, a calcium
channel blocker and ryanodine, a calcium channel stimulator, on the photoperiodic induction of flowering was also studied.
Ruthenium red, when applied before and during an inductive 16-h dark period, slightly inhibited flowering, whereas ryanodine,
when applied before and during a 12-h long subinductive night, stimulated flower bud formation. We also confirmed evidence
that Ca2+ ions are involved in the photoperiodic induction of flowering. Thus, the obtained results may suggest the involvement of
cyclic ADPR-activated Ca2+ mobilization in the photoperiodic flower induction process in Pharbitis nil. 相似文献
107.
108.
How plant‐feeding insects distribute themselves and utilize their host plant resources is still poorly understood. Several processes may be involved, and their relative roles may vary with the spatial scale considered. Herein, we investigate small‐scale patterns, namely how population density of a gall midge is affected by individual growth form, phenology, and microsite characteristics of its herb host. The long‐lived plant individuals vary much with regard to number of shoots, flower abundance, and flowering phenology. This variation is connected to site characteristics, primarily the degree of sun exposure. The monophagous insect galls the flowers of the host plant – an easily defined food resource. It is a poor disperser, but very long‐lived; diapausing larvae can stay in the soil for many years. Galls were censused on individual plants during 5 years; from a peak to a low in gall population density. Only a very small fraction of the flowers produced (<0.5%) were galled even in the peak year. Nevertheless, most plant individuals had galls at least 1 year. In a stepwise multiple regression, plant size (number of shoots) was found to be the most important predictor of gall density (galls/flower). However, gall density decreased more than one order of magnitude over the plant size range observed. There was also a weak effect of plant phenology. Early flowering plants had lower gall densities than those starting later. Sun exposure had no direct effect on gall density, but a path analysis revealed indirect effects via the timing of flowering. Gall population change was highly synchronous in different parts of the study area with no significant decrease in synchrony with distance. 相似文献
109.
Clelia De-la-Pe?a Dayakar V. Badri Zhentian Lei Bonnie S. Watson Marcelo M. Brand?o Marcio C. Silva-Filho Lloyd W. Sumner Jorge M. Vivanco 《The Journal of biological chemistry》2010,285(40):30654-30665
Proteins found in the root exudates are thought to play a role in the interactions between plants and soil organisms. To gain a better understanding of protein secretion by roots, we conducted a systematic proteomic analysis of the root exudates of Arabidopsis thaliana at different plant developmental stages. In total, we identified 111 proteins secreted by roots, the majority of which were exuded constitutively during all stages of development. However, defense-related proteins such as chitinases, glucanases, myrosinases, and others showed enhanced secretion during flowering. Defense-impaired mutants npr1-1 and NahG showed lower levels of secretion of defense proteins at flowering compared with the wild type. The flowering-defective mutants fca-1, stm-4, and co-1 showed almost undetectable levels of defense proteins in their root exudates at similar time points. In contrast, root secretions of defense-enhanced cpr5-2 mutants showed higher levels of defense proteins. The proteomics data were positively correlated with enzymatic activity assays for defense proteins and with in silico gene expression analysis of genes specifically expressed in roots of Arabidopsis. In conclusion, our results show a clear correlation between defense-related proteins secreted by roots and flowering time. 相似文献
110.
Many examples of plant-insect interactions have shown that selection from herbivores can act on flowering and fruiting phenology.
In Ulex europaeus (Fabaceae), escaping seed predation resulted in extended, but variable flowering periods, with some plants flowering from
autumn until spring and others flowering only in spring. The present study aims at understanding how gorses can have a high
reproductive success during winter despite harsh climatic conditions and low number of pollinators. We measured pollen production,
flower size and seed production in spring and winter, and compared the different seasons. The pollination success of flowers
was high in both seasons. The flowers produced as much pollen, and were of comparable size in spring and winter, but they
stayed open twice as long in winter than in spring. The high pollination rate we observed was thus due to the longer opening
period of flowers and the high attractiveness of flowers during winter. However, pod abortion was higher in winter, with 43%
of the flowers in winter and 75% in spring producing ripe pods. Antagonistic selective pressures exerted by biotic and abiotic
interactions may, therefore, have lead to the observed flowering polymorphism, and allow U. europaeus to thrive in various climates, thus, increasing its invasiveness in different countries. 相似文献