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排序方式: 共有263条查询结果,搜索用时 62 毫秒
1.
高等植物叶片的衰老   总被引:41,自引:5,他引:36  
蛋白质丧失是叶片衰老的一个早期表现,降解的蛋白主要是可溶性蛋白中部分Ⅰ蛋白,随衰老加深,叶绿素含量、光合速率下降,保护酶活性降低。叶片这些衰老的表现是体内活性氧、自由基代谢失调累积的结果。  相似文献
2.
植物叶片衰老与氧化胁迫   总被引:38,自引:0,他引:38  
叶片衰老是叶片生长发育进程中的最后阶段,与活性氧伤害有着密切的关系。介绍了植物叶片衰老过程中活性氧产生及清除系统的变化,讨论了对水分胁迫与氧化胁迫的交叉抗性,并对下一步的研究作出了展望  相似文献
3.
The expression of several Arabidopsis thaliana senescence-associated genes (SAGs) in attached and/or detached leaves was compared in response to age, dehydration, darkness, abscisic acid, cytokinin, and ethylene treatments. Most of the SAGs responded to most of the treatments in a similar fashion. Detachment in darkness and ethylene were the strongest inducers of both SAGs and visible yellowing. Detachment in light was also a strong inducer of SAGs, but not of visible yellowing. The other treatments varied more in their effects on individual SAGs. Responses were examined in both older and younger leaves, and generally were much stronger in the older ones. Individual SAGs differed from the norms in different ways, however, suggesting that their gene products play a role in overlapping but not identical circumstances. Some SAGs responded quickly to treatments, which may indicate a direct response. Others responded more slowly, which may indicate an indirect response via treatment-induced senescence. Four new SAGs were isolated as part of this work, one of which shows strong similarity to late embryogenesis-abundant (Lea) genes.  相似文献
4.
Gene expression during leaf senescence   总被引:32,自引:5,他引:27  
5.
Large-scale identification of leaf senescence-associated genes   总被引:27,自引:0,他引:27  
Leaf senescence is a form of programmed cell death, and is believed to involve preferential expression of a specific set of "senescence-associated genes" (SAGs). To decipher the molecular mechanisms and the predicted complex network of regulatory pathways involved in the senescence program, we have carried out a large-scale gene identification study in a reference plant, Arabidopsis thaliana. Using suppression subtractive hybridization, we isolated approximately 800 cDNA clones representing SAGs expressed in senescing leaves. Differential expression was confirmed by Northern blot analysis for 130 non-redundant genes. Over 70 of the identified genes have not previously been shown to participate in the senescence process. SAG-encoded proteins are likely to participate in macromolecule degradation, detoxification of oxidative metabolites, induction of defense mechanisms, and signaling and regulatory events. Temporal expression profiles of selected genes displayed several distinct patterns, from expression at a very early stage, to the terminal phase of the senescence syndrome. Expression of some of the novel SAGs, in response to age, leaf detachment, darkness, and ethylene and cytokinin treatment was compared. The large repertoire of SAGs identified here provides global insights about regulatory, biochemical and cellular events occurring during leaf senescence.  相似文献
6.
三唑酮对绿豆幼苗叶片衰老的延缓作用   总被引:26,自引:0,他引:26  
三唑酮处理可提高离体绿豆(PhaseolusradiatusL.)幼苗叶片叶绿素和蛋白质含量。叶片衰老过程中超氧物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(AsAPOD)活性及抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量降低。20mg/L三唑酮可提高POD、AsAPOD活性和AsA、GSH含量,对SOD、CAT活性无影响。丙二醛(MDA)含量在叶片衰老过程中提高,并与POD、AsAPOD活性和AsA、GSH含量呈显著负相关,三唑酮可降低MDA含量。表明三唑酮有提高植物对膜脂过氧化作用的保护能力,延缓叶片的衰老作用。  相似文献
7.
土壤水分胁迫对小麦根系与旗叶衰老的影响   总被引:25,自引:3,他引:22  
随土壤水分胁迫加剧,旗叶,根中的超氧化物歧化酶,过氧化氢酶活性降低,腊脂过氧化产物丙二醛含量增加,花后14d为膜脂过氧化作用加重的转折点,此时受水分胁迫愈重,旗叶与根中SOD,CAT活性降低愈迅速,MDA含量迅速升高,根系活力,旗叶与根中可溶性蛋白含量骤降,加重了膜脂过氧化程度,降低了清除了自由基能力,加速植株衰老。  相似文献
8.
Senescence mechanisms   总被引:24,自引:0,他引:24  
9.
Cloning and characterization of tomato leaf senescence-related cDNAs   总被引:23,自引:0,他引:23  
Senescence-related cDNA clones designated SENU1, 4, 5 (senescence up-regulated) and SEND32, 33, 34, 35 and 36 (senescence down-regulated) isolated from a tomato leaf cDNA library [9] were characterized. Southern analysis showed that SEND32 is encoded by a single-copy gene while SEND33, 34, 35, 36 and SENU1 and SENU5 are members of small gene families. DNA and protein database searches revealed that SEND32, SEND35, SENU1 and SENU5 are novel cDNAs of unknown function. SEND33 encodes ferredoxin, SEND34 encodes a photosystem II 10 kDa polypeptide and SEND36 encodes catalase. The SENU4 sequence is identical to the P6 tomato protein previously reported to be pathogenesis-related [46]. The mRNA levels of SENU1, 4 and 5 increased during leaf senescence and SENU1 and SENU5 were also expressed at high levels during leaf development and in other plant organs. The SENU4 mRNA was associated more specifically with leaf senescence, although low expression was also detected in green fruit. The mRNAs for all SEND clones decreased during tomato leaf development and senescence and all except SEND32 were expressed at low levels in other plant organs. The accumulation of mRNA homologous to SENU4 and the decrease in abundance of SEND32 provide good molecular markers for leaf senescence.  相似文献
10.
Isolation,characterization, and mapping of the stay green mutant in rice   总被引:23,自引:0,他引:23  
Leaf color turns yellow during senescence due to the degradation of chlorophylls and photosynthetic proteins. A stay green mutant was isolated from the glutinous japonica rice Hwacheong-wx through N-methyl-N-nitrosourea mutagenesis. Leaves of the mutant remained green, while turning yellow in those of the wild-type rice during senescence. The stay green phenotype was controlled by a single recessive nuclear gene, tentatively symbolized as sgr(t). All the phenotypic characteristics of the mutant were the same as those of the wild-type lines except for the stay green trait. The leaf chlorophyll concentration of the mutant was similar to that of the wild-type before heading, but decreased steeply in the wild-type during grain filling, while very slowly in the mutant. However, no difference in photosynthetic activity was observed between the stay green mutant and the yellowing wild-type leaves, indicating that senescence is proceeding normally in the mutant leaves and that the mutation affects the rate of chlorophyll degradation during the leaf senescence. Using phenotypic and molecular markers, we mapped the sgr(t) locus to the long arm of chromosome 9 between RFLP markers RG662 and C985 at 1.8- and 2.1-cM intervals, respectively. Received: 29 April 2001 / Accepted: 17 July 2001  相似文献
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