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1.
本文研究了天山北麓干旱、湿润2种不同水分条件下拟南芥(Arabidopsis thaliana)光合生理、形态及发育特征的自然适应特点。结果表明:分枝数、株高、相对适合度(角果质量)、莲座叶面积等特征在不同水分下差异极显著;根质量与相对适合度、莲座叶面积、水分利用效率和光合速率之间表现了正相关,胞间二氧化碳浓度与光合速率、水分利用效率之间表现了负相关;选择梯度分析得出,干湿水分条件下分枝数、株高、莲座叶面积均表现定向选择;主成分分析发现,光合生理特征整合在处理间有一定的规律性,表现出拟南芥物种特征整体协调一致性较强,对环境响应具有较大的趋同性;通径分析发现,水分利用效率、枝质量、株高、角果数对相对适合度直接产生较大影响,因而在通径模型中设置为直接路径特征,将莲座叶面积通过分枝数、花期、角果数,花期通过角果数到达相对适合度的过程设置为间接路径,这些特征通过间接路径对相对适合度间接产生较大影响。  相似文献   
2.
Summary A protocol was developed for the preparation of Cucumis sativus var Straight 8 protoplasts that incorporates a two-step Ficoll® gradient and results in a high percentage of viable, debris-free protoplasts suitable for the transient expression of foreign genes. Polyethylene glycol and electroporation were compared for their effect on protoplast transfection with commonly used reporter genes. Using a polyethylene glycol method, cucumber protoplasts transfected with a plasmid containing the -glucuronidase gene showed high expression levels, while protoplasts transfected with a plasmid containing the chloramphenicol acetyl transferase gene showed levels of activity that were barely distinguishable from mock-transfected controls. Tomato ringspot virus genomic RNA was also transfected into the protoplasts, and the assembly of viral particles was confirmed.  相似文献   
3.
A new concise and facile method was explored to synthesize a series of novel chalcone derivatives containing a purine and benzenesulfonamide moiety and their antiviral properties were evaluated against TMV and CMV. Biological assays indicated that several of the derivatives exhibited significant anti-TMV and anti-CMV activities in vivo. In particular, compound d2 displayed excellent inactivating activity against TMV, with the EC50 value of 51.65?μg/mL, which was better than that of ribavirin (150.45?μg/mL). Molecular docking showed that there are four hydrogen bonds between compound d2 and TMV coat protein (TMV-CP). Compound d2 demonstrated strong binding capacity to TMV-CP with Ka?=?1.58?×?105?L/mol and Kd?=?12.16?μM. These findings indicated that chalcone derivatives are worthy of further research and development as templates for new antiviral agents.  相似文献   
4.
The effect of polyamines (PAs) on nitric oxide (NO) generation was investigated in cucumber (Cucumis sativus cv. Dar) primary leaves using bio-imaging with an NO-selective fluorophor, DAF-2DA. Seedlings pretreated with PAs and subjected to water deficit showed early (after 5 h) and transient NO production. The amplitude of the response depended on the form of the applied polyamine. Spermine (1.0 mM) and spermidine (1.0 mM) induced higher NO-dependent fluorescence compared with putrescine (1.0 mM) and the control. The NO production was blocked by tungstate, an inhibitor of nitrate reductase, and partially by an inhibitor of nitric oxide synthase (NOS-like) enzymes. NO donor administration preceding drought had no effect on endogenous PA levels but was positively correlated with an alleviation of water deficit-induced membrane permeability and lipid peroxidation. Application of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a membrane-permeable NO scavenger, markedly reversed the NO donor effects. Similarly, pretreating seedlings with PAs resulted in lower ion leakage from the membrane and modified lipid peroxidation. The results indicate that NO may act downstream of PAs in cucumber seedlings under water stress.  相似文献   
5.
Hydrogen peroxide (H2O2), an active oxygen species, is widely generated in many biological systems. The present study demonstrates that H2O2 was generated in seedling explants after the primary roots were removed, and it mediates the auxin response prior to adventitious root formation in cucumber (Cucumis sativus L. Ganfeng 8). When compared with the controls, treatment of cucumber seedling explants after primary roots removal with either 20–40 mM H2O2 or 10 μM IAA significantly increased the number of adventitious roots, and treatment with 10–50 mM H2O2 significantly increased the fresh weight of adventitious roots. The effects of H2O2 on promoting the formation and growth of adventitious roots were eliminated by 2 mM ascorbic acid, 100 U CAT or 1 μM DPI, and the effects of IAA were eliminated by 4 mM ascorbic acid, 100 U CAT or 5 μM DPI. Treatment with either 4 mM ascorbic acid or 1–5 μM DPI inhibited the formation and growth of adventitious roots, and these inhibitory effects were partly reversed by exogenous H2O2.Furthermore, a higher concentration of endogenous H2O2 was detected in seedling explants 3 h after the primary roots were removed. However, in 10 μM DPI-treated seedling explants, the concentration of endogenous H2O2 was markedly reduced by DPI. Results obtained suggest that H2O2 may function as a signaling molecule, involved in the formation and development of adventitious roots in cucumber.  相似文献   
6.
铅胁迫对黄瓜幼苗抗氧化酶活性及同工酶的影响   总被引:35,自引:2,他引:33  
采用水培法和聚丙烯酰胺凝胶电泳法,研究铅胁迫对黄瓜幼苗过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及同工酶的影响.结果表明,铅胁迫下黄瓜幼苗地上部POD活性除第5天外均随铅浓度的增加而逐渐降低,POD同工酶谱带和表达量减少.在0~500 mg·L-1铅浓度范围内,SOD活性随铅浓度的增加而增加,第7天达到最大值后急剧下降,低于同期对照值,900 mg·L-1铅处理SOD活性随时间的延长逐步降低,SOD酶谱带和表达量与铅浓度呈负相关.CAT酶谱带无明显变化,而表达量存在差异.  相似文献   
7.
黄瓜苗根围拮抗细菌X3的分子鉴定   总被引:9,自引:2,他引:7  
采用生理生化、Biolog和16S rDNA分子鉴定3种不同方法,对抑制黄瓜苗期猝倒病病原真菌的细菌菌株X3进行了鉴定.生理生化鉴定显示该菌株为Pseudomonas aeruginosa;而Biolog鉴定显示其为P.spinosa;进一步对该菌株作16S rDNA基因的测定与分析,表明其与已报道的P.aeruginosa 16S rDNA具有93.7%的同源性,二者在所建系统发育树中处于同一分枝,据此确定该菌株为P.aeruginosa。  相似文献   
8.
Development and characterization of microsatellite markers in Cucumis   总被引:21,自引:0,他引:21  
This study provides a set of useful SSR markers and describes their development, characterization and application for diversity studies.Sixty one Cucumis SSR markers were developed, most of them (46) from melon (Cucumis melo L.) genomic libraries. Forty of the markers (30 melon and 10 cucumber SSRs) were evaluated for length polymorphism in a sample of 13 melon genotypes and 11 cucumber (Cucumis sativus L.) genotypes. PCR-amplification revealed up to six size alleles among the melon genotypes and up to five alleles among the cucumber genotypes, with mean gene-diversity values of 0.52 and 0.28 for melon and cucumber, respectively. These differences are in accordance with the known narrower genetic background of the cucumber. SSR data were applied to phylogenetic analysis among the melon and cucumber genotypes. A clear distinction between the ’exotic’ groups and the sweet cultivated groups was demonstrated in melon. In cucumber, separation between the two sub-species, C.sativus var. sativus and C.sativus var. hardwickii,was obtained. Conservation of SSR loci between melon and cucumber was proven by sequence comparisons. Received: 17 April 2000 / Accepted: 16 May 2000  相似文献   
9.
Nitrogen fertigation of greenhouse-grown cucumber   总被引:2,自引:0,他引:2  
Summary This greenhouse study investigated the response of trickle-irrigated cucumber (Cucumis sativa cv. ‘Petita’) to three N levels applied with every irrigation via the irrigation stream. The plants were grown in pots filled with 12 kg of soil. Water containing 5.8, 11.8, or 17.8 mmol N/l, and uniformly supplied with 2.0 and 3.9 mmol/l of P and K, respectively, was applied two to three times daily. In all treatments of 0.3 leaching fraction was allowed. The resulting total N applications were 15.7, 31., and 47.2 g N/plant. The total amount of water applied was 1851/plant. Total N and NO3-N, in lajinae and petioles, increased with increasing N level whereas P and K in generated decreased. Although different NO3/NH4 ratios in the treatments may have influeced the response to N, it could be concluded that the highest yield was obtained with 11.8 mmol N/1 due to increased number of fruit. In the root volume of this treatment the NO3-N concentration in the soil solution was aroun 7 mmol/1 for most of the growing season. The dry matter concentration of fruits was not affected by the N levels. It was concluded that 11.8 mmol N/1 applied with every irrigation via the irrigation stream is adequate to cover the needs of greenhous-grown cucumber for higher yield (9.42 kg/plant over a harvesting period of 93 days).  相似文献   
10.
Curt Leben 《Plant and Soil》1986,91(1):139-142
Summary Survival ofPseudomonas syringae pv.lachrymans with seedling cucumber roots, root washings, rhizosphere soil, and nonrhizosphere soil was determined 7–8 days after the soil surface was watered with a cell suspension of the bacterium. Plants were in pots in the green-house and soil was not sterilized. Survival was best with roots and root washings, next best in rhizosphere soil, and poor in nonrhizosphere soil.  相似文献   
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