冷锻炼对提高水稻幼苗抗寒性及其细胞器膜结构稳定性的影响   总被引：8，自引：0，他引：8  

邵继荣  刘永胜 《作物学报》1999,25(5):567-573

冷锻炼对不同水稻品种抗寒力的增强作用有明显差异。抗寒品种冷锻炼后，超氧物歧化酶(SOD)活性提高，细胞质膜电导率下降，这一状态能在5d低温处理((50℃, 4000Ix/12 h)中保持；而冷敏品种冷锻炼后，SOD活性只能在最初的2d内保持，并随低温处理时间延长而丧失，其电导率、丙二醛(MDA)、脯氨酸以及细胞器膜系统超微结构，都表  相似文献   

Use of chlorophyll fluorescence to evaluate the cold acclimation and freezing tolerance of winter and spring oats   总被引：16，自引：0，他引：16  

F. Rizza    D. Pagani    A. M. Stanca  L. Cattivelli 《Plant Breeding》2001,120(5):389-396

The efficiency of the excitation capture by open Photosystem II (PSII) reaction centres was measured by the F_v/F_m ratios in a collection of winter and spring oats in order to assess the effects of hardening and freezing on the functionality of PSII and also the suitability of a chlorophyll fluorescence‐based method to screen oat cultivars for frost tolerance. A significant reversible decrease in F_v/F_m was found in all genotypes during acclimation to low, non‐freezing temperatures. F_v/F_m analysis appears to be an attractive test for the evaluation of frost tolerance in oats, being rapid, non‐invasive and capable of monitoring a trait related to a crucial stage in the acquisition of frost tolerance. It is more sensitive and precise than other standard methods and highly correlated with field‐evaluated frost damage. The measurements made during recovery 1 or 2 days after stress when the visual symptoms are not yet expressed, were especially advantageous because of the large variability in genotype response. The r‐values (close to 0.8) were reduced due to the non‐standard behaviour of the winter cultivar ‘Aintree’. The cold acclimation response of this genotype has been analysed in detail and the limits of artificial freezing tests are discussed.  相似文献   

前期干旱锻炼对谷子水分利用效率的影响   总被引：19，自引：0，他引：19  

郭贤仕  山仑 《作物学报》1994,20(3):352-356

以谷子为材料，在盆栽条件下研究了前期干旱锻炼对谷子水分利用效率的影响。实验结果表明，不论苗期还是拔节期的干旱锻炼，都使其生育后期的水分利用效率显著提高，水分利用效率提高的原因并不是由于耗水绝对量的减少，而是干旱锻炼改善了叶片的同化功能，使同化能力的增长超过了蒸腾的增加。从叶片净光合速率、叶绿素含量、  相似文献   

机械设计中的一个误区     

刘长生 《中南林业科技大学学报(自然科学版)》1999,(3)

针对长期以来一些著作和许多技术人员所认定的“零件表面在高频淬火时产生较高的残余压应力，对提高其耐磨性有利”的观点进行了分析，认为这种观点基本是不正确的．同时，用具体的数据阐明：采用合理的回火处理，在零件表面硬度降低不大的条件下，尽量减少摩擦表面的这种残余压应力，才是减少磨损的正确方法，并对最佳回火温度进行了研究  相似文献   

提高内燃机缸套耐磨性的探讨     

梁淇泽  杨玉侠 《吉林农业大学学报》1988,(1)

根据内燃机缸套窘损特点,在修造过程中,从改善缸套的润滑条件及表面强化工艺角度,分析和探讨了提高缸套耐磨性的有效途径。  相似文献   

造纸黑液与无机肥对草地早熟禾抗寒性的影响比较     

文秋明  莫海涛  张小勇 《草业科学》2011,28(1):47-52

在晚秋自然降温过程中,通过对草地早熟禾（Poa pratensis）叶片生理生化指标和表观品质的跟踪测定、比较,研究了造纸黑液和无机肥对草地早熟禾抗寒性的影响。结果表明,造纸黑液和无机肥不同程度地提高了草地早熟禾抗寒锻炼的效果。无机肥显著促进了草地早熟禾叶片游离脯氨酸（Fpro）的积累,最大含量为868.95 μg/g。造纸黑液显著提高了草地早熟禾叶片的超氧化物歧化酶（SOD）活性和可溶性糖（WSS）含量,最大值分别为201.16 U/g和137.15 μg/g。无机肥处理延长草坪绿期约10 d,造纸黑液处理延长草坪达40 d。相对于无机肥,造纸黑液更为显著地提高了草地早熟禾的抗寒性,并保持了较高的草坪观赏性。  相似文献   

SQJ—Z小型嫁接器刀片热处理工艺研究     

靳永宽  裘祖荣  郝巧玲 《山西农业大学学报(自然科学版)》1994,(2)

本文对ＳＱＪ─—Ｚ小型嫁接器刀片的选材和热处理工艺进行了研究。试验结果表明，采用６５Ｍｎ钢成型后的刀片进行等温分级淬火、低温回火的热处理工艺，可以使刀片获得硬度和强韧性的最佳配合。  相似文献   

蚕豆试管苗移栽技术研究   总被引：2，自引：0，他引：2  

刘洋 《杂粮作物》2003,23(6):344-345

通过对春蚕豆试管苗炼苗方法与移栽技术的研究，总结出一套蚕豆试管苗炼苗移栽的工艺流程，研究发现通过闭口-开口炼苗后。试管苗长势好。抗性强。成苗率达90％以上。  相似文献   

软氮化对YF40　Mn　VS钢弯曲疲劳性能的影响     

庄哲峰  林伟业 《福建农林大学学报(自然科学版)》1994,(2)

ＹＦ４０　Ｍｎ　ＶＳ钢经软氮化后表层硬度由２３７ＨＶ提高到６３４ＨＶ，而心部显微组织和硬度无明显变化，疲劳强度σ－１由原来的３３２ＭＰａ提高到４６７ＭＰａ．与形变表而复合强化的４０Ｃｒ和４５钢相１比，ＹＦ４０ＭｎＶＳ钢具有更好的强化效果．  相似文献   

New approach for using trunk growth rate and endocarp development in the irrigation scheduling of young olive orchards     

David Pérez-López  Alfonso Moriana  Hava Rapoport  Nicolas Olmedilla  Francisco Ribas 《Scientia Horticulturae》2008

Trunk diameter variation (TDV) is considered one of the most promising tools for automating the scheduling of fruit tree irrigation, and trunk growth rate (TGR) a possible indicator of TDV values. The use of TGR in commercial orchards is less common in olive trees than in other species, possibly because the influence of the environment, orchard age and the presence of developing fruit on the olive tree seasonal TGR pattern is poorly understood. In this study the trunk growth rate (TGR) seasonal progression was characterized in fully irrigated young olive trees during fruiting and non-fruiting years. In both years, at the beginning of the season, a period with an almost linear increase was found, mainly determined by temperature. In the non-fruiting year TGR remained almost constant after that initial increase, while during the fruiting year a significant decrease occurred at approximately 25 days, from values around 0.2 mm day⁻¹ to values around 0.1 mm day⁻¹. Since midday shoot water potentials were not affected, this variation was likely not produced by water stress conditions. In addition, the lack of relationship between trunk growth rate and air temperature indicated that the TGR decrease in the fruiting year was not determined either by air temperature. The period of decreasing TGR values, however, coincided with the time that the endocarp reached its maximum transverse area, a significant moment for fruit development which precedes pit hardening. These results suggest that the traditional period where regulated deficit irrigation is done, “the pit hardening”, may be indicated easier and more accurate for TGR decrease and endocarp expansion.  相似文献