水肥耦合对紫花苜蓿叶绿素含量和硝酸还原酶活性的影响

在温室盆栽条件下,以氮、磷、水用量和配比作为变量,以叶绿素含量和硝酸还原酶活性为目标函数建立方程,研究水肥耦合对敖汉苜蓿叶绿素含量和硝酸还原酶活性的影响.结果表明:(1)叶绿素含量和硝酸还原酶活性与氮、磷、水密切相关,呈二次幂函数关系.(2)叶绿素回归方程中,各因素的作用为氮＞磷＞水,且氮为正值,磷、水为负值,磷-水交...     

Antioxidative activity associated with chilling injury tolerance of muskmelon (Cucumis melo L.) rind

‘Galia’ melon (Cucumis melo L. var. reticulatus) is a climacteric fruit with a short storage life. To prevent over-ripening, fruits are stored at 4–6 °C, which also results in chilling injury (CI) that appears as numerous brown spots on the surface of the fruit. It has been suggested that exposure of ‘Galia’ fruits to high growth temperatures in the field renders them sensitive to low storage temperatures. Activity profile of the antioxidative enzymes catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) was monitored in the rind of ‘Galia’ fruits during low-temperature storage, to associate each enzyme's activity with CI incidence. Experiments were performed with low-temperature-sensitive and tolerant varieties, 5080^S and 1537^T respectively, and included a pre-storage treatment of hot-water wash of 5080^S fruits.     

Hypolipemic and hypoglycaemic activity of bergamot polyphenols: From animal models to human studies

Bergamot juice produces hypolipemic activity in rats though the mechanism remains unclear. Here we investigated on the effect of bergamot extract (BPF) in diet-induced hyperlipemia in Wistar rats and in 237 patients suffering from hyperlipemia either associated or not with hyperglycaemia. BPF, given orally for 30 days to both rats and patients, reduces total and LDL cholesterol levels (an effect accompanied by elevation of cHDL), triglyceride levels and by a significant decrease in blood glucose. Moreover, BPF inhibited HMG-CoA reductase activity and enhanced reactive vasodilation thus representing an efficient phytotherapeutic approach in combating hyperlipemic and hyperglycaemic disorders.     

印度Ladakh地区沙棘叶、果实、种子蛋白含量与叶中硝基酶活性之间的关系

沙棘是一种非豆科固氮植物。其蛋白的定性定量评价显示,除了海拔2530~3350m间的种类M-8以外,具有结节的植物普遍比没有结节的植物具有更高的蛋白质含量。在17个沙棘种类的叶,果实,种子中蛋白质水平随着海拔高度的变化在9.65~21.07mg/g鲜重之间变化。其中种子为1.62~5.11mg/g,果实中为0.68~3.51mg/g。数据显示,叶中硝基还原酶活性与蛋白含量存在正相关关系。在海拔较低的Ladakh地区(2500~2850m)发现的种类(M-2,8,13)比海拔高于2850m的种类具有更高的蛋白质含量(12.38~15.10mg/g鲜重),此外,在河畔生长的品种比丘陵斜坡上生长的种类蛋白含量更高。在荒芜的Ladakh地区,这种沙棘叶可能为人或动物提供多样的食物供给。可以鼓励农业或商业种植沙棘用于饲料。     

Physiological effects of pruning in rose plants cv. Grand Gala

The effect of pruning in rose plants (cv. Grand Gala) was studied in different types of leaves, focusing on chlorophyll (Chl) a fluorescence, carbohydrates, ammonium content, nitrate reductase (NR) activity and biomass parameters. Results on pruned plants showed a higher maximum efficiency of photosystem II (PSII) of dark-adapted leaves, a higher actual quantum yield and a higher proportion of PSII reaction centres that are open, but a lower non-photochemical quenching, indicating a lower energy dissipation as heat, compared to non-pruned plants. These results related to Chl a fluorescence, indicate that pruned plants have a higher capacity for better promoting the photosynthetic light reaction than non-pruned plants. The increased nitrate reductase activity in pruned compared with non-pruned plants, can result from a higher photosynthetic activity resulting in a lower NH₄⁺ accumulation in leaves. Pruning promoted a large number of metabolic sinks (flower removal) that may cause depletion of stored carbohydrates flowing from lower plant parts (arched shoots) to the new developing flower shoots. However, although in a lower concentration, carbohydrate contents were sufficient to promote the development of new flower shoots since the yield was similar for pruned and non-pruned plants. However, pruned plants showed higher turgor than non-pruned plants.     

聊红国槐叶片硝酸还原酶活性测定方法的研究

以聊红国槐(Sephora japonica Liao hong)为试验材料,探讨体内法测定其叶片硝酸还原酶活性的若干问题,分析比较了硝酸盐诱导,2,4-二硝基苯酚,三氯乙酸及煮沸等因素对硝酸还原酶活性测定结果的影响,以寻求体内法测定聊红国槐叶片硝酸还原酶活性的最佳条件.试验表明:体内法是一种操作简便可靠测定聊红国槐叶片硝酸还原酶活性的方法,这为进一步研究国槐的氮代谢奠定生物学基础.     

沼肥配制的营养土在黄瓜育苗中的应用效果

以津春4号黄瓜为试材,用黄瓜育苗普通营养土配比(园土:农家肥:细沙=6:3:1)作对照,研究了不同沼肥配制的营养土在黄瓜育苗中的应用效果。试验结果表明,不同配比的营养土培育的黄瓜苗在形态指标、光合色素含量及净光合速率、根系活力、过氧化物酶(POD)活性和硝酸还原酶(NR)活性均存在差异,其中以园土:沼肥:沙子=7:2:1配制的营养土在黄瓜育苗中的效果最佳。     

Phosphate solubilization by Chryseobacterium sp. and their combined effect with N and P fertilizers on plant growth promotion

The capabilities of soil microorganisms to solubilize phosphate have been known for many years, but their isolation and use as crop inoculants have met with little success. Thirty-five bacterial isolates were screened for their phosphate-solubilizing ability, and two of them, PSR10 and RGR13, identified through 16S rDNA sequencing as Chryseobacterium sp. PSR10 and Escherichia coli RGR13, respectively, screened for plant growth promotion in the greenhouse. Seed inoculation of Macrotyloma uniflorum (horsegram) by Chryseobacterium sp. PSR10 showed better plant growth promotion in sterilized and unsterilized soil under greenhouse conditions and was selected for a field experiment with 100, 50 and 30% of recommended doses of nitrogen and phosphorus fertilizer. Seed inoculation with 50% of the recommended dose of nitrogen and phosphorus increased plant growth (agronomical parameters, chlorophyll content, nitrate reductase activity, phosphorus content and crop yield). We conclude that effective plant growth-promoting bacterium Chryseobacterium sp. PSR10 broadens the spectrum of phosphate solubilizers available for field applications and might be used together with 50% dose of nitrogen and phosphate.     

Effects of inhibitors for signaling components on the expression of the genes for nitrate reductase and nitrite reductase in excised barley leaves

Nitrate-induced accumulation of mRNAs for nitrate reductase and nitrite reductase was strongly inhibited by treatment with inhibitors of Ca²⁺ channels, protein phosphatases, and tyrosine protein kinases in excised barley leaves. It was shown that these components may be involved in the nitrate-response signaling pathways for the expression of nitrate and nitrite reductase genes in barley leaves.