Application of Native Tree Species to Urban Forest

Native tree species plays important roles in theconstruction of urban forest. It bears manyadvantages, such as sufficient cultural context, strongecologic adaptability, high performance-cost ratio andconvenient management. The authors put forwardseveral countermeasures based on the existingproblems. And this paper will be very helpful inunderstanding why native tree species are put in animportant position in the construction of urban forest.The plant is the material basis of constructing urban…     

Restoring Mountain Slope Forests by Strip-cutting Shrubs in the Upper Reaches of Minjiang River, Sichuan, China： A Biodiversity-oriented Silvicuture Experiment

INTRODUCTIONMinjiangRiver,oneofprimarytributariesoftheYangtzeRiver,thatisthelongestriverinChinaandthethirdlongestintheworld,isoriginatedfromtheeasternpartofQinghai-TibetPlateauwherethegeomorphologyismainlycharacterizedbyhighmountainswithdeepvalleys(ZhangRongzu,1992).Becauseslopelandsaccountforalargeproportionofvegetatedareaandthesoillayerisverythininmostcases(ChenGuojie,2000),theupperreachesofMinjiangRiverisidentifiedtobeanunstableandfragileecosystemthatiseasilydeterioratedbyanthropog…     

淮河流域农田CO2和热通量日、季节变化特征

利用淮河流域寿县国家气候观象台2007年7月至2008年6月全年每天48 个时次的湍流通量涡度观测资料,分析近地层CO2和热通量的日变化和季节变化,结果表明：CO2、净辐射和潜热通量具有明显的日变化和季节变化。日变化幅度随季节变化明显,表现在春、夏两季CO2、净辐射和潜热通量日变化幅度大, 冬、秋季变化幅度较小;分季节研究发现CO2通量在夏季和春季（水稻及小麦生长期）较大,而在下垫面无作物以及被积雪覆盖时只有-0.051 mg﹒m-2﹒h-1 ～-0.047 mg﹒m-2﹒h-1,整个观测期CO2通量日平均值约为-0.59mg﹒m-2﹒h-1,农田明显为CO2的汇;净辐射和潜热通量在5 月份最大, 1 月份最小。     

Research on protoplast preparation and culture in Gladiolus hybridus Hort.

Protoplasts prepared from the aseptic leaves of Rose Supreme in Gladiolus hybridus Hort. were cultured. The yield of protoplasts with vigour was the highest under the following conditions: 1.5% cellulase Onzuka RS, 0.5% pectinase Y-23, 0.6 mol· L~(-1) mannitol, pH 5.8, digestion time 2 h, and temperature 27℃. After isolation and purification, protoplasts were cultured in solid and liquid combined medium, which included KM8P, 0.6 mol· L~(-1) mannitol, 1.0 mg· L~(-1) 2, 4-D, 0.2 mg· L~(-1) NAA and 0.2 mg· L~(-1) KT. The division of the protoplasts first emerged in medium after cultured 4 days, and emerged only a few times.     

Effects of cold stress on hypothalamic corticotrophin-releasing and thyrotropin-releasing hormone messenger RNA levels in chickens

There is increasing evidence that stress can activate the hypothalamic-pituitary-adrenal-axis and hypothalamic-pituitary- thyroid-axis,and further affect the synthesis and secretion of corticotrophin-releasing hormone(CRH)and thyrotropin-releasing hormone(TRH).To evaluate the effect of cold stress on the hypothalamic CRH and TRH messenger RNA(mRNA)levels in Yisha chickens,male Yisha chickens were subjected to acute(1,6,12 h)and chronic(5,10,20 d)cold stress(12±1)℃.Hypothalami were collected for assessment of mRNA levels by semi-quantitative RT-PCR.Acute stress resulted in a significant decrease of CRH mRNA levels at 6 and 12 h,and a significant increase of TRH mRNA levels at every stress time point.Chronic cold stress resulted in a significant increase of CRH mRNA levels and a significant decrease of TRH mRNA levels compared with the control group at every stress time point.The results suggest that the two genes differently respond to cold stress at the mRNA levels.And the different degrees of cold stress will produce different effects on the identical gene.     

安庆市夏玉米涝渍灾害指标研究

为了研究渍害对安庆市夏玉米生长发育及产量的影响,通过运用安庆市1960—2011年多种农业气象资料,采用降水概率≤20%与≥80%分位数法和采用FAO（联合国粮农组织）方法计算夏玉米不同时段需水量与同时段降水量比较,综合2种方法设计了夏玉米不同生育时段的综合涝渍指标。并采用涝渍强度指数验证综合涝渍指标的正确性。结果表明：安庆市夏玉米全生育期综合涝渍指标为 ≥731.8 mm,6月上旬到9月下旬逐旬综合涝渍指标为：≥66.8 mm、≥70.3 mm、≥124.9 mm、≥89.4 mm、 ≥78.2 mm、≥92.2 mm、≥84.7 mm、≥76.6 mm、≥49.2 mm、≥47.4 mm、≥41.4 mm、≥27.7 mm。采用综合涝渍指标划分典型的涝渍年份与采用涝渍强度指数划分涝渍年份对比相似率达81.8%,表明安庆市综合涝渍指标符合当地实情,具有实用价值。     

江淮分水岭地区干旱分析

通过对江淮分水岭地区气象和水文资料以及多年旱涝状况的分析，得出了该地区基本的气候特点。该地区气候可划分为东、中、西3部分，西部气候湿润而稳定，旱涝灾害较少；中部气候干燥而稳定，旱灾多于涝灾；东部气候变化复杂，分析认为东部气候类型是整个江淮分水岭地区的基本气候类型，中、西部气候是在该基本气候类型基础上受山地和水域等周围地理环境影响而形成的。     

马铃薯生理性叶斑病鉴定与诊断方法

为了准确诊断马铃薯生理性叶斑病,对该病害进行了室内鉴定和田间调查。结果表明:马铃薯生理性叶斑病是由于刮风,使叶片间互相摩擦、叶片与地面摩擦、叶片被大风吹翻转后雨滴的直接击打或雨滴溅起的泥沙击打,从而使叶肉组织受到坏死后形成的斑点;该病典型症状为病斑褐色,有时有光泽,圆形或不规则,1~5 mm大小,有时多个病斑愈合;病斑周围无晕圈,无霉层或菌脓菌胶等病征,且病斑多,分布较均匀。     

基于DNA条形码技术的海南龙血树和剑叶龙血树分子鉴定

海南龙血树(Dracaena cambodiana)和剑叶龙血树(Dracaena cochinchinensis)是传统名贵中药血竭在中国的重要基源植物,但其在苗期至成株期之间难以用传统分类学进行鉴定,而DNA条形码技术为这一科学问题的解决提供了可能。本研究利用已经通过形态学鉴定的海南龙血树和剑叶龙血树叶片开发了两种龙血树的DNA条形码,发现ITS2具有较大的变异度,可与来自叶绿体的trnL-trnF作为鉴定的分子标记,并基于变异最大范围构建了分子标记的示意图。为探究龙血树的分子生态学上的进化地位,基于两种龙血树的ITS2序列与其同源的41个物种的ITS2序列构建了分子进化树,发现龙血树属植物与龙舌兰科、百合科组成分支的亲缘关系近于含有天门冬科的分支,此结果为海南龙血树和剑叶龙血树的种质资源鉴定提供了分子标记,并为龙血树属在百合纲确切分类地位的确定提供了理论和技术支持。     

高浓度CO2对马尾松光合速率的影响

提高环境CO2浓度可扩大适宜马尾松中幼林光合作用的光合有效辐射强度(PAR)范围,有利于提高用光能利用率.正常CO2浓度环境中,马尾松中幼林的适宜光合作用范围为300～600 μmol·m-2·s-1,5.50×10-4环境中的适宜范围为300～850 μmol·m-2·s-1,7.00×10-4环境中,光合有效强度达1 100 μmol·m-2·s-1时马尾松中幼林仍然具有较强的光合作用.高温也有利于提高马尾松中幼林的光合速率,但温度过高则会对光合作用产生抑制.300～600 μmol·m-2·s-1的光强范围内,正常CO2浓度环境中的临界温度约为36.0℃,在5.50×10-4的环境中约为39.0℃.高浓度CO2有利于提高马尾松中幼林光合速率,也加快了大气CO2消耗,CO2浓度的增加和植物消耗之间可能会在一个较高的CO2浓度水平上达到动态平衡.