Study on Physiological Characteristics of Three Different Cold-resistant Tomato Strains

[Objective]The aim was to study cold-resistant indexes and physiological characters of three different cold-resisitant tomato strains selected under natural conditions. [Method]With 3-4 weeks tomato seedlings as tested materials,through simulating external environment conditions by the cold treatment in lab,the survival ratio and growth status of seedlings were identified; by studying the morphological change of in vitro leaves after cold treatment and determining the relative conductivity,the cold-resistant degree of different tomato strains was identified and the correlation between conductivity and survival rate was analyzed; the variation of soluble sugar and praline content in plant of tomato was determined under the condition of cold stress. [Result]The results showed that leaf morphological changes,size of conductivity and growth status of different tomato strains after cold treatment have significant differences; the variation of soluble sugar contents in plant has significant differences,while the variation of proline content has no significant differences. [Conclusion]There is a certain correlation between conductivity and survival rate under cold treatment conditions,and plant cold tolerance is related to accumulation of soluble sugar content.

Genetic parameter evaluation for growth and cold resistance traits of the giant freshwater prawn Macrobrachium rosenbergii

The giant freshwater prawn Macrobrachium rosenbergii distributed from tropical to subtropical regions,is a warm-water species,and its survival temperature is 14-35°C,which greatly limits its culture cycle and culture area in China.Therefore,it is urgent to cultivate a new high quality,high yield variety with improved cold-resistance,but the genetic parameters for cold-resistance traits are unknown in M.rosenbergii.In this study,the cold-resistance of adult M.rosenbergii populations was tested using the indoor artificial cooling method.Individuals were selected from 139 families of Shufeng G3 generation and cultured for 200 days.A linear mixed model was constructed by ASReml-R to evaluate the genetic parameters of the cold-resistance trait(cooling degree hours,CDH)and growth traits(body weight,BW,and body length,BL)based on the restricted maximum likelihood(REML)method.The results show that the heritability of CDH was low(0.12±0.05),while the growth traits(BW and BL)had low to moderate heritability,with 0.20±0.06 for BW and 0.06±0.04 for BL.The phenotypic and genetic correlation between BW and BL was significantly positive,but significantly negative phenotypic and genetic correlations were detected between CDH and BW and between CDH and BL.Furthermore,the analysis of the differences between cold-resistance and phenotypic traits showed that the female reproductive status,exoskeleton hardness and claw number of adult prawns had a great influence on the cold-resistance of M.rosenbergii(P<0.05),indicating that adults with claws and hard exoskeletons are preferred as parents in subsequent breeding selection.The present results can be attributed to the selection and breeding of a new cold-resistant variety of M.rosenbergii.

Design and Data Analysis of a New Type of Antifreezing Cup-Type Wind Velocity Sensor

In most areas of China, affected by the environment of low temperature and high humidity, the wind speed sensor and wind direction sensor are frozen and cannot output data in autumn, winter or the alternation of winter and spring. In order to solve the freezing situation of the wind sensor, this paper designs a new type of antifreeze wind speed sensor. After meteorology performance testing and field observation tests, the correlation coefficient of the observation data is demonstrated, and the data curve is fitted. The result shows the sensor is stable, and has a good antifreeze effect, the data output is reliable.

长沙城市森林树种冰冻灾害的调查与反思

2008年1月中旬至2月初,湖南遭遇50年以来罕见的严重冰冻灾害,大面积交通受阻,供电中断,给全省人民的生产生活带来严重影响。持续了20多天的冰冻,对长沙城市森林损害巨大,大量木竹倒伏、折枝、断干、翻蔸,其中栽植密度较大的景观林、生态林和湿地松、火炬松、桉树、香樟、桂花、广玉兰、毛竹、观赏竹类等常绿树种及古树名木受冰冻雪压尤为严重。通过对灾情的调查与反思,提出在我国南方城市森林建设中,要加强抗灾预警机制的建设,要重视选用抗冰冻雪压性能强的乡土树种。

A Preliminary Study on Tissue Culture and Transformation of Casuarina equisetifolia L.

[Objective] The paper aimed to study the tissue culture and transformation of C. equisetifolia. [Method] C. equisetifolia were used as experimental materials to explore the effects of three conditions including callus induction, adventitious bud dif- ferentiation and Agrobacterium-mediated transformation on transformation rate of C. equisetifolia. [Result] The appropriate plant growth regulator combination on induction and differentiation of C. equisetifolia adventitious buds was DCR＋5.0 mg/L of 6-BA＋ 0.5 mg/L of NAA; hygromycin was selected for the selective pressure and co-culture time was 3 d; 94 stains of transgenic C. equisetifolia were obtained with the initially- established transgene system via Agrobacterium-mediated method, and 61 stains were PCR-positive plants according to the results of PCR detection. [Conclusion] The study had laid the foundation for tissue culture and transgene research of C. equi- setifolia.

Cold-Resistant Rubbers Based on Flexible Polymer Chains

Comprehensive Summary,As one of the three types of polymeric materials,rubber has played an irreplaceable role in various fields such as industrial production,aerospace,military,and national defense.Improving the cold resistance of rubbers and extending their service temperature range have always been one of the main focuses in rubber research.However,there have been few detailed public reports or literatures on the progress or summary of cold-resistant rubbers,creating an invisible barrier for new researchers wishing to enter this field of research.Therefore,starting from the basis of polymer physics,this review introduces the research difficulties in this field and systematically summarizes the research progress in constructing cold-resistant rubbers based on three different types of flexible polymer chains in recent years.In addition,several important properties of cold-resistant rubbers including mechanical performance,oil resistance,and self-healing ability are also discussed along with the summary of recent progresses.Finally,the future challenges and prospects of cold-resistant rubbers are discussed.

Overwintering covered with soil or avoiding burial of wine grapes under cold stress:Chinese wine industry’s past and future,challenges and opportunities

In northwest China,where winter is extremely cold and the grapevine is vulnerable to freezing damage,the application of soil covering has promoted the vigorous development of the local grape and wine industries.However,in recent years,the negative effects of burying soil for cold protection on the environment have gradually emerged.In some viticultural regions,the phenomenon of"summer forest,winter desert"has appeared.Therefore,it is urgent for the Chinese grape industry to find a better solution to overwinter safely and environmentally friendly.This review summarizes the advantages and disadvantages of widely used solutions to overwinter such as covering vines with soil,breeding of cold-resistant grapes,cold-resistant cultivation model,physical and chemical covering materials,and protected grape facilities were reviewed.Future overwintering measures were proposed which avoid burial and grape overwintering research directions.It also provides a theoretical foundation and technical support to improve grape yield and quality in northwest China.