Change of 3 Kinds of Enzyme Activity and Soluble Sugar in 3 Chinese Cabbage Varieties with Different Resistance Level During the Process of Plasmodiophora brassicae Infecting Their Roots

There are different levels of resistance in Chinese cabbage varieties against clubroot.The content of catalase(CAT),peroxidase(POD),phenylalanin ammonia-lyase(PAL),Super Oxide Dismutase(SOD)and soluble sugar activities of 3cultivars with different clubroot-resistant levelswere detected after inoculation in this study.The results suggest that the changing rates of CAT,PAL and SOD contents of resistance cultivars after inoculation were higher than those of susceptible cultivars(Baigengbaiye>Zaobaicaitai>Huangjinxiaobaicai);the POD activities of resistance cultivars reached a peak on an earlier day than those of susceptible cultivars;the increasing rate of soluble sugar of susceptible cultivars was higher than that of the resistance cultivars,and ended with two peaks.Therefore,the four enzymes(CAT,POD,PAL and SOD)and soluble sugar may be used as physiological and biochemical reference indexes for the resistance identification to clubroot after inoculation with P.brassicae.     

Physiology Mechanism of Metabolisms in the Middle Scales of Lilium davidii var. unicolor Bulbs Stored at Low Temperature for Dormancy-Release

Changes in carbohydrate, phenols, free amino acids and endogenous hormones in middle scales of Lilium davidii var. unicolor bulbs during the 101 days storage at 2, 6 and 10℃ in moist sawdust were studied. The results indicated that as the storage time increased and the storage temperature delined, contents of starch and abscisic acid (ABA) decreased markedly, and the level of total soluble sugar, phenols, gibberellic acid (GA3) and indole acetic acid (IAA) increased sharply. In the first 34 days, the contents of the above substances changed most actively. Correlation analysis revealed that the increase in content of total soluble sugar and phenols was respectively caused by activation of amylase and phenylalanine ammonia-lyase (PAL). During the storage, the content of free amino acids decreased, and the level of arginine was the highest and changed most remarkably. According to the results of stepwise regression analysis and path analysis, we could primarily conclude that the metabolism of carbohydrates, phenols and free amino acids in the middle scales may be mainly regulated by endogenous GA3.     

Effect of Drought Stress During Flowering Stage on Starch Accumulation and Starch Synthesis Enzymes in Sorghum Grains

Starch content is a key factor affecting sorghum grain quality. The research of sorghum grain starch accumulation and the related synthesis enzyme activities has great signiifcance for understanding the mechanisms of starch metabolisms. The differences between a high and a low starch content sorghum hybrids （Tieza 17 and Liaoza 11, respectively） in grain starch accumulation and the related synthesis enzyme activities were assessed following imposition of water stress during lfowering stage. The total starch, amylase and amylopectin accumulation all decreased at the mid-late stage of grain iflling under drought stress during lfowering stage. The maximum and mean accumulation rates also decreased. During grain iflling, soluble starch synthase （SSS）, granule-bound starch synthase （GBSS）, starch branching enzyme （SBE）, and starch debranching enzymes （DBE） activities were all affected, though differently. Drought stress reduced starch accumulation in a larger extent for Tieza 17 than Liaoza 11. Drought stress during lfowing stage reduced starch synthesis enzyme activities, thus reducing starch accumulation in grains, and the differences between starch components were also demonstrated under drought stress.     

Effect of Endophytic Fungus on Pyrola calliantha H. Andr Responsed to Cold Stress

This study measured the antioxidant enzyme activities of Pyrola under cold and endophytic fungal infection conditions[i.e.,peroxidase (POD),catalase (CAT) and superoxide dismutase (SOD)],and the contents of malondialdehyde (MDA),soluble sugar and soluble protein.In addition,the changes in the anatomical structure of Pyrola vegetable organ during cold stress upon inoculation with a synergistic endophytic fungus were also analyzed.It was found that the soluble sugar and soluble protein contents and POD,SOD and CAT activies of Pyrola all increased,when the plants were exposed to temperature of–5℃.In particular,the MDA contents and the POD activies significantly increased compared with those of the control.In addition,the soluble sugar and soluble protein contents increased during the treatment,which involved in both inoculation with an endophytic fungus and low temperature;however,with a reduction in the concentration of endophytic fungus,those two indicators decreased.The optimal concentration of endophytic fungus was 5×10~7 cfu ·mL~(-1).From the anatomical structure of Pyrola root,endophytic fungi were found to improve the health of Pyrola in cold weather.These results showed that endophytic fungi played a vital role in the growth of Pyrola,which was an evergreen plant that could survive exposure to low temperature.     

Effects of Low Temperature on Physiological Responses of Two White Clover Cultivars

In order to explore the effects of low temperature on the two different genotypes of white clover, electrical conductivity(EC), soluble sugar, malondialdehyde(MDA) and some other physiological indexes of plants were compared under laboratory conditions. Seedlings of Longping No.1 and Koala were undergone a series of degrading temperatures set in turn 25℃, 10℃, 5℃, 0℃, –5℃ and –10℃. The results showed that the activities of superoxide dismutase(SOD), electrical conductivity, soluble sugar, free proline and MDA increased obviously with the decrease of stress temperature, while the content of starch decreased, and the content of soluble protein increased first and then decreased during the process. Comprehensive assessments on physiological responses to low temperature stress indicated that the cultivar Longping No.1 had stronger cold resistance than that of cultivar Koala.     

Study on Accumulation Rule of Carbohydrates in Soybean （Glycine max（L.） Merrill）

Three soybean cultivars, Hefeng25 （HF25）, Suinongl4 （SN14） and Longxuanl （LX1） were used as materials and the accumulation features of carbohydrates were studied in leaves and stems. The results showed that the soluble sugar content in leaves and stems appeared the same trend of higher-lower-higher in three varieties. The changes of sucrose content in leaves appeared the same rule with that of soluble sugar, that is higher-lower-higher, while presented a rising trend in stems. The content of starch in leaves varied as a change of double apexes. The content of starch in stems appeared a change of single apex. In the same stage, there were some differences among carbohydrates. The content of soluble sugar and sucrose in SN14 was higher, and the starch content was lower.     

苜蓿蓟马抗性与生理活性相关性研究(英文)

[Objective] The experiment explored of resistance of different Medicago sativa through synthetic variations of all physiological indexes and the correlation analysis between physiological activity and damage degree after thrips damage. [Method] According to studying physiological activity (POD activity, SOD activity, PPO activity, PAL activity, MDA content and free proline content) of alfalfa in alfalfa resistance to different number of thrips, the correlation between physiological activity and resistance was investigated. [Result] It was shown that there were negative correlations among POD, SOD, PPO, PAL, MDA, free praline and the number of thrips, and there were negative correlations among POD, SOD, PPO, PAL, MDA, free praline and CAT. The content changes of POD,SOD,PPO,CAT,MDA and free proline in high resistant alfalfa were slow and PAL was quick and the activities of PPO,PAL,CAT were high, and the activities of POD、SOD were low. [Conclusion] The research provided theoretical basis and materials for identifying resistance varieties of alfalfa to thrip.     

Effect of Alkali Stress on Soluble Sugar, Antioxidant Enzymes and Yield of Oat

Alkali stress can cause severe crop damage and reduce production. However, physiological processes involved in alkali stress in oat seedlings are not well understood. In this study, physiological responses and yield of oat to alkali stress were studied using the alkali-tolerant oat genotype Vao-9 and the alkali-sensitive oat genotype Baiyan 5. The results were: (i) low concentrations of alkali stress (25 and 50 mmol L-1) significantly reduced the yield and grain weight while increased the oat grain number per spike. A negative correlation between yield and malondialdehyde (MDA) content at the jointing and grain filling stages and positive correlations between yield on one hand and superoxide dismutase (SOD), and peroxidase (POD) activities on the other at the jointing stage were observed. There was a positive correlation between MDA and soluble sugar at the grain filling stage; (ii) soluble sugar content was increased at the jointing and grain filling stages and decreased at the heading stage by alkali stress; (iii) alkali stress increased the SOD activity during the heading and grain filling stages, and increased the POD activity at the heading stage. As compared to the control, the increase of MDA contents in alkali-treated oat was observed, during the jointing, heading and grain filling stages; (iv) under alkali stress, the oat genotype Vao-9 showed higher antioxidant enzyme activity and lower soluble sugar contents during the heading stage, and lower MDA contents than those in the oat genotype Baiyan 5 under alkali stress. The result suggested that the high ROS scavenging capacity and soluble sugar levels might play roles in oat response to alkali stress.     

Regulation of Development and Endogenous Polyamine Level in Chinese Cabbage (B. Campestris ssp. Pekinensis)

The endogenous polyamine levels were tested at every developmental stage in different ecotypes of the Chinese cabbage. The results showed that polyamincs (PAs) were decreased in the process of flower bud initiation and fornfation, but the floral stem formation and elongation were accompied by PAs increase. The level of Spm was related to the bolting date of Chinese cabbage. During the inducing of flower bud initiation and elongation of floral stem, and the changes of Spm were reversed between early bolting date and late bolting cultivars, but they have the same requirment for Spd for the starting of flower bud initiation and the starting of bolting. The level of Spd changed little during entire developmental stage for early bolting cultivars, but a lot for late bolting cultivars. The time that the highest level of Put appeared is related to the bolting date of Chinese cabbage.     

加拿大的农业科技及其组织管理

本文详细介绍了加拿大农业科技体制改革及其组织,其总的研究发展方向由加拿大政府掌握.把科技政策、研究发展方向和国家需要结合起来通盘考虑,自上而下提出科研项目.     

保护地蔬菜病虫害发生特点及其综合防治

根据保护地蔬菜病虫害发生特点,掌握综合防治方法,把病虫为害损失控制在经济允许水平之下,达到优质、高产、低成本和农产品无污染的目的。     

秦汉时期的中印交通与农业科技文化交流

对秦汉时期中国与印度的交流进行考证,在丰富的史料基础上,研究了当时中印的交通状况与农业科技文化交流。     

矿难与科学技术

煤矿事故时有发生．分析认为发生事故的本质原因是工作人员缺乏有关的科学技术知识．发展、掌握、运用科学技术。提高人员的科学技术素质。不仅能促进经济发展，而且能保障人身安全，战胜灾害(包括煤矿灾害)．     

网络文化与高校思想政治工作研究

近年来,在社会经济的不断推动之下,互联网技术得到了飞速发展,随之而来的则是网络文化的兴起,这对于高校思想政治工作带来了较大的冲击,但同时也是一种新的挑战;因而各高校要对网络文化树立正确的认知,将其与高校思想政治工作相互结合,因势利导,才能推动高校思想政治工作的不断深入。本文针对当前网络文化与高校的思想政治工作展开进一步的研究与分析。     

高校思想政治教育与创新创业教育的双向构建

高校顺应社会经济发展要求,越来越重视思想政治教育与创新创业教育的融合。分析了思想政治教育与创新创业教育的互动关系,阐述了思想政治教育与创新创业教育双向构建优势,提出了构建的对策:教育理念层面实现互相融合、教学内容层面实现丰富升华、实践活动层面实现有机结合和组织管理层面实现系统完备。     

雪松的栽植及后期管护

雪松是常绿的观赏树种,栽植时要选择恰当的栽植季节、苗木和采取正确的挖掘方法,后期管护浇水、施肥,加强高温季节以及越冬的管护。