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41.
以71-3-150、GM256、SH6及M9 4种苹果(Malus)矮化砧木的1年生枝条为试材,进行-20℃、-25℃、-30℃、-35℃、-40℃低温处理,用电导法配合Logistic方程,求得拐点温度(LT50)即半致死温度,并对其电导率、可溶性蛋白含量和POD酶活性等指标进行了测定比较。结果表明:测得的电解质渗出率呈典型的S型曲线,与相应的低温呈极显著负相关;71-3-150、GM256、SH6及M9的半致死温度分别为-40.63℃、-39.29℃、-34.10℃、-30.10℃;抗寒性强的71-3-150和GM256能保持较高的可溶性蛋白含量和POD酶活性。 相似文献
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M. C. Rebolledo M. Dingkuhn P. Péré K. L. McNally D. Luquet 《Journal of Agronomy and Crop Science》2012,198(5):374-384
Achieving early vigour, that is, rapid dry matter accumulation, is a priority in rice crop improvement, but this trait is complex and not well understood genetically and physiologically. This study tested the hypothesis that the development rate (DR) contributes to early vigour. Two diversity panels were phenotyped during vegetative stage for traits constituting early vigour (shoot dry weight, SDW; relative growth rate, RGR) or contributing to early vigour (tillering, leaf size, DR). The first panel comprised 169 genotypes from all major genetic groups of Oryza sativa and was phenotyped under irrigated upland conditions in the field (Philippines, Exp1). The second panel with 190 genotypes representing the diversity of the tropical japonica group was phenotyped in pots in a greenhouse (Montpellier, France, Exp2). Results from field and pot experiment pointed out that DR, tillering and leaf size were positively correlated with RGR and SDW, although the contribution of leaf size was small. DR was positively correlated with tillering but both were negatively correlated with leaf size. DR vs. RGR correlation was conserved in subsets of genotypes with similar leaf size and tillering, suggesting an effect of DR on RGR independent of the other traits. DR is a promising, still underexploited trait contributing to rice early vigour, requiring further genetic and physiological characterization. 相似文献
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本研究旨在检测内源性绵羊肺腺瘤反转录病毒(enJSRV)与干扰素-τ(IFN-τ)在妊娠早期蒙古绵羊子宫内膜组织的表达以及enJSRV的表达与外周血孕酮水平变化的关系。运用TaqMan实时荧光定量PCR技术和电化学发光法对enJSRV和IFN-τ在妊娠早期蒙古绵羊子宫内膜组织相对表达及孕酮水平进行了测定。实时荧光定量PCR结果显示,enJSRV和IFN-τmRNA在妊娠早期绵羊子宫内膜组织有不同程度的表达。SAS统计学软件分析得出,子宫内膜组织中enJSRV mRNA在妊娠12~14d(交配日为0d)表达较高,2~10、16~30d的表达均低于前者。IFN-τmRNA仅在妊娠12~25d表达,14d达其峰值,30d就不能检出,且差异都极显著(P<0.01)。电化学发光法结果显示,孕酮水平在妊娠2d为0.4ng·mL-1,以后升高,妊娠8~16d维持在8.3ng·mL-1左右,在妊娠19~30d孕酮水平有所下降,30d为2.5ng·mL-1。以上结果提示,子宫内膜组织中enJSRV mRNA的表达与外周血孕酮含量及IFN-τ的变化高度相关,且enJSRV在胎盘的形态发生及生殖生物学方面发挥重要作用。 相似文献
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Henk J. Schouten 《European journal of plant pathology / European Foundation for Plant Pathology》1991,97(3):139-149
WhenErwinia amylovora grows, in an intercellular space of a host, and fills this space, further multiplication or swelling may create a pressure, and may cause tearing of host tissue. Theoretically, this bacterial pressure equals the actual water potential of the host tissue minus the water potential at which the bacterial biomass would completely fill the intercellular space, but without exerting pressure.Simulation runs indicate that, when the pressure increases, the extracellular slime ofE. amylovora shrinks by releasing water, thus allowing further production of bacterial dry matter. The slime remains around the bacterial cells as a dense substance, low in water content, having a strong capacity to swell when the pressure induces tearing apart of the host tissue. Simulation runs show that the pressure attains its highest values at evening and night.Some fire blight symptoms that illustrate the evidence of bacterial pressure are discussed. 相似文献
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反刍家畜粗饲料品质评定的指标及其应用比较 总被引:23,自引:0,他引:23
本文结合笔者的研究结果就评定粗饲料品质的单项指标粗蛋白、中性洗涤纤维、消化率与动物的粗饲料干物质随意采食量以及综合指标粗饲料相对值(RFV)、粗饲料分级指数(GI)在粗饲料品质评定上的应用进行了比较,指出:上述各单项指标并不能客观地反映粗饲料的品质,应使用综合指标。由于GI考虑了粗饲料中的能氮互作,对粗饲料的分级比RFV更精确。 相似文献
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Scaevola aemula is a popular ornamental crop cultivated as a bedding plant or for hanging baskets. We characterized gas exchange properties of S. aemula ‘New Wonder’ in response to photosynthetically active radiation (PAR), carbon dioxide concentration, and leaf temperature. Net CO2 assimilation rate (A) was responsive to CO2, exhibiting a saturation when intercellular CO2 concentration (Ci) was greater than 600 μmol mol−1. Net CO2 assimilation rate and dark respiration rate (Rd) were 23.1 and 2.3 μmol m−2 s−1, respectively, at 25 °C and PAR = 1500 μmol m−2 s−1. Net CO2 assimilation rates were similar at leaf temperatures between 20 and 30 °C but significantly reduced at 15 °C. These gas exchange results were used to test the extendibility of a coupled gas exchange model previously developed for cut-roses. Utilizing the gas exchange data measured at 25 °C leaf temperature, several model parameters were independently determined for S. aemula. Model predictions were then compared with observations at different leaf temperatures. The model predicted the rates of net CO2 assimilation and transpiration of S. aemula reasonably well. Without additional calibration, the model was capable of predicting the temperature dependence of net CO2 assimilation and transpiration rates. Applying the model to predict the effects of supplemental lighting and CO2 enrichment on canopy photosynthesis and transpiration rates, we show that this model could be a useful tool for examining environmental control options for S. aemula production in the greenhouse. 相似文献
50.
辽西地区相对资源承载力与可持续发展研究 总被引:3,自引:0,他引:3
本文讨论并改进了相对资源承载力的概念、研究思路和计算方法,选择具有代表性的辽西地区,实证分析1988—2004年辽西地区相对土地资源承载力、相对经济资源承载力、相对生活水平承载力和综合承载力的演变和空间差异,预测2010年和2015年辽西地区的人口超载规模,分析辽西地区相对资源承载力存在问题的原因,提出辽西地区实现可持续发展的对策。 相似文献