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991.
Cucumber chilling-resistant cultivar Changchun mici and -sensitive cultivar Beijing jietou were used in this study to investigate the effects of exogenous PAs on protection against chilling injury as well as on changes of physiological features, and the fluctuation of free PAs content in the leaves under chilling stress. Upon chilling treatment, free spermidine (Spd), spermine (Spm) and putrescine (Put) were remarkably induced in the leaves of cv. Changchun mici 1 day after treatment. The induction of Put declined thereafter, whereas Spd and Spm levels increased steadily. In the leaves of cv. Beijing jietou, Put content was increased only at 1 day after chilling while Spd content decreased significantly upon chilling treatment. Chilling reduced soluble protein content, and decreased the activities of antioxidant enzymes, including superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) only in Beijing jietou. However, these changes could be renovated by exogenous application of Put and Spd. It was also found that pretreatment with Put and Spd diminished the increased electrolyte leakage and malondialdehyde (MDA) content caused by chilling in the leaves of both cultivars. Pretreatment of methyglyoxal-bis-(guanylhydrazone) (MGBG), the PAs biosynthetic inhibitor cancelled the effects of PAs in most of the treatments. Moreover, histochemical staining and quantitative measurements showed that exogenous application of Put and Spd eliminated but MGBG exaggerated the hydrogen peroxide (H2O2) accumulation caused by chilling stress, especially in leaves of Beijing jietou. Interestingly, Changchun mici was found to contain higher endogenous free PAs contents compared to Beijing jietou. While no significant difference of SOD, POD and CAT activities was found between non-chilling Changchun mici and Beijing jietou seedlings, the former exhibited higher APX activity than the latter. These results suggest that PAs play important roles in the tolerance of cucumber against chilling stress, which is most likely achieved by acting as oxidative machinery against chilling injury. 相似文献
992.
AIM:To investigate the expression of nestin, a kind of cytoskeletal protein in cultured murine podocytes and the role of nestin in the maintenance of the podocyte structure.METHODS:The immortalized murine podocytes were cultured. The expression of nestin was determined by immunofluorescence. In differentiated podocytes, the expression of nestin was knock-down by RNAi. The effect of nestin knock-down was examined by Western blotting and immunofluorescence. The projections longer than maximal length of the cell body in which the cells transfected with siRNA and control vector that contained nonhomologous oligo were counted, respectively. RESULTS:Nestin siRNA markedly reduced or abolished nestin expression. In cells transfected with nestin siRNA, the percentage of cells with processes was significantly lower than that in cells transfected with control vector (77.0%±6.3% vs 16.0%±4.6%, n=3, P<0.01). CONCLUSION:Nestin may play an important role in maintaining normal function of podocytes. 相似文献
993.
AIM: To observe the damage induced in the primary cultured rat cortical neurons by oxygen/glucose deprivation and reintroduction, and to investigate the neuroprotective mechanism of salvianolic acid B (SalB). METHODS: Primary cultured rat cortical neurons were randomly divided into the control group, the model group and the SalB group. The cell model was established by oxygen/glucose deprivation for 3 h followed oxygen/glucose reintroduction for 24 h. The cortical neurons viability was determined by MTT assay. The leakage rate of lactate dehydrogenase (LDH) was measured by chromatometry. The mitochondrial membrane potentials (MMP) and the apoptosis rate were quantitatively analyzed by flow cytometry. The cytosolic free calcium was assessed using LSCM. The morphologic changes of neuronal nuclei were observed by Hoechst 33342 fluorescence staining. RESULTS: Compared to the model group, the cortical neurons viability, the survival rate and the fluorescence value of MMP in the SalB group were obviously increased (P<0.05,P<0.01). In addition, in the SalB group, the leakage rate of LDH, the fluorescence intensity of cytosolic free calcium and the apoptosis rate were significantly lower than those in the model group (P<0.01). CONCLUSION: The neuroprotective mechanism of SalB in the oxygen/glucose deprivation and reintroduction neurons would be due to the fact that SalB maintains the MMP and the calcium homeostasis. 相似文献
994.
大白菜叶片长宽性状的QTL定位 总被引:1,自引:0,他引:1
利用一套大白菜双单倍体(DH)群体和包含287个分子标记的遗传图谱,运用复合区间作图法对叶长、无柄叶长、有柄叶长、叶宽、叶柄长、叶柄宽6个叶部形态学性状进行QTL定位及遗传效应的分析。结果表明:在4个连锁群上共检测到12个QTL,分别为叶长相关的3个,无柄叶长相关的2个,有柄叶长相关的2个,叶宽相关的1个,叶柄长相关的2个,叶柄宽相关的2个。各位点的遗传贡献率介于7.5 %~18.9 %之间。其中,叶长与叶柄长的QTL存在共定位,叶宽与叶柄宽的QTL也存在共定位。 相似文献
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999.
用品种稳定性参数及高稳系数(HSC),对2004~2005年参加国家甜菜区试中的5个品种在甘肃武威市黄羊镇和酒泉地区的试验结果进行了综合分析,结果表明:BTS356的丰产、稳产性好.两年平均根产量和产糖量分别较对照陇糖2号增产40.62%和39.94%,差异达极显著水平,含糖率18.73%;对黄化病、白粉病、立枯病的抗性优于对照,具有较高的应用价值,适宜在甘肃省河西走廊生态条件下推广种植。 相似文献
1000.