硝酸钙处理对低温下紫花苜蓿耐寒性及幼苗生长的影响

采用温箱培养、室内盆栽的方法,通过50mmol·L^-1的Ca（NO3）2溶液浸种、叶面喷施及人工低温处理,研究了Ca（NO3）2对紫花苜蓿幼苗生长及抗寒能力的影响。试验结果表明：Ca（NO3）2降低了紫花苜蓿的叶绿素含量,提高了叶面积系数以及幼苗的成活率。     

塔里木河中游胡杨(Populus euphraticu)“肥岛”的养分特征研究

利用传统统计学和地统计学方法,对塔里木河中游胡杨"肥岛"的养分特征进行了研究.结果表明:胡杨周围的土壤养分向冠幅内聚集,具有较强的富积强度,形成了明显的"肥岛"特征.大胡杨冠幅下4种养分(有机质、碱解氮、有效磷、速效钾)分别比冠幅外高64.94%,72.87%,61.70%和185.20%;中胡杨为5.36%,5.39%,47.02%和93.43%;小胡杨为27.96%,10.20%,67.48%和218.59%;但不同发育阶段土壤养分的富积率具有一定的差异,有机质表现为极显著,碱解氮和速效钾表现为显著,而有效磷没有显著差异.单株胡杨土壤养分变异系数属中等强度,半方差函数模型除碱解氮为高斯模型外,其他为球状模型, 块金值/基台值[C0/(C C0)]的比值均在25%附近,表明空间相关性强烈,整体看来土壤养分的变异性主要由结构性因素引起的.胡杨养分的"肥岛"作用范围(7.5～11.1 m)大于冠幅半径(5 m);通过克里格插值图分析,胡杨立地土壤养分表现出不同程度的"肥岛"效应.     

Effects of Nitrogen Forms on Carbon and Nitrogen Accumulation in Tomato Seedling

Utilization of organic nitrogen （N） is an important aspect of plant N assimilation and has potential application in sustainable agriculture. The aim of this study was to investigate the plant growth, C and N accumulation in leaves and roots of tomato seedlings in response to inorganic （NH4^＋-N, NO3^-N） and organic nitrogen （Gly-N）. Different forms of nitrogen （NH4^＋-N, NO3^--N, Gly-N） were supplied to two tomato cultivars （Shenfen 918 and Huying 932） using a hydroponics system. The plant dry biomass, chlorophyll content, root activity, total carbon and nitrogen content in roots and leaves, and total N absorption, etc. were assayed during the cultivation. Our results showed that no significant differences in plant height, dry biomass, and total N content were found within the first 16 d among three treatments; however, significant differences in treatments on 24 d and 32 d were observed, and the order was NO3^--N 〉 Gly-N 〉 NH4^＋-N. Significant differences were also observed between the two tomato cultivars. Chlorophyll contents in the two cultivars were significantly increased by the Gly-N treatment, and root activity showed a significant decrease in NHa^＋-N treatment. Tomato leaf total carbon content was slightly affected by different N forms; however, total carbon in root and total nitrogen in root and leaf were promoted significantly by inorganic and organic N. Among the applied N forms, the increasing effects of the NH4^＋-N treatment were larger than that of the Gly-N. In a word, different N resources resulted in different physiological effects in tomatoes. Organic nitrogen （e.g., Gly-N） can be a proper resource of plant N nutrition. Tomatoes of different genotypes had different responses under organic nitrogen （e.g., Gly-N） supplies.     

Ca对AZ31镁合金CO2激光焊接接头组织和性能的影响

采用添加填充材料的CO2激光焊接工艺对AZ31镁合金薄板进行焊接,研究了不同Ca含量对焊缝金属的显微组织和力学性能的影响.结果表明：当激光功率为1 500 W,焊接速度为3 m/min时, AZ31镁合金CO2激光焊接的焊缝金属中添加一定量的σCa＜0.19%元素,可以得到成分相对较均匀、组织细小的焊缝.当填充带材为AZC04(焊缝中σCa=0.19%)时,焊缝区晶粒相对细小,析出相细小弥散,此时焊接接头的力学性能最优,焊接效率基本可达到100%.     

RT-PCR法克隆广谱抗病基因TGA2及其蛋白表达载体构建

本试验采用Trizol Reagent提取拟南芥总RNA,设计相关引物,采用反转录PCR方法克隆TGA2转录因子;利用酶切连接方法,将该基因正向导入蛋白表达载体.经过相关检验,TGA2转录因子连接到pMXB10载体内含肽(Intein)的N端,成功构建包含TGA2转录因子的pMXB10-TGA2蛋白表达载体.     

齐口裂腹鱼日粮中钙和磷及适宜钙磷比的研究

研究了齐口裂腹鱼日粮中适宜钙磷含量及其钙磷比,试验分2期进行,第Ⅰ期饵料中钙磷总量不同,在基础饵料钙磷比为1：0．54的基础上调整钙磷比梯度为1：0．5,1：0．54,1：1,1：2,1：3,1：4;第Ⅱ期饵料中钙磷比梯度基本保持不变,而钙磷总量均为6．66％。试验时间2个月,以鱼的增重率为试验指标。结果表明,齐口裂腹鱼对钙的需要量为1．48％-3．33％,对磷的需要量为1．48％-4．995％,对钙、磷总需要量为2．96％-6．66％,随钙的增加磷应以1：3的比例增加。     

实现职业院校学生思想政治工作的"四个创新"

结合长期职业教育经历,分析了当前职业院校学生思想政治工作新特点,从观念创新体现超前性、机制创新体现灵活性、形式创新体现多样性、渠道创新体现实效性等方面对职业院校思想政治工作进行了有益的探索。     

国外图书馆先进经验与我国图书馆服务的可持续性发展

分析了国外图书馆在服务领域内的各种先进经验，针对我国图书馆服务工作的现状，提出了深化与可持续性发展的各项措施：开展我国图书馆工作中的特殊群体服务；实现图书馆联网，开展馆际互借；开展各种特色服务，拓展服务范围；咨询人员专业化，全面开展咨询工作,尤其是数字参考咨询服务，提升我国图书馆的咨询服务水平。

     

基于叶片面积玉米叶片保绿度开花后衰减特性初步研究

采用Excel工作表Origin7.0统计分析软件对基于绿叶面积玉米叶片保绿度开花后衰减特性进行了初步研究,结果表明:玉米开花后叶片保绿度衰减符合方程y=aeb-cx/(1+eb-cx);不同基因型玉米叶片保绿度衰减启动时间、最大衰减速率和最大衰减速率出现时间等衰减特性差异较大;即使相同基因型在不同环境条件下叶片衰减特性也不尽相同.采用y=aeb-cx/(1+eb-cx)模拟方程能比较全面揭示叶片保绿度的动态变化过程.     

Regulation of Calcium on Peanut Photosynthesis Under Low Night Temperature Stress

The effects of different levels of CaCl 2 on photosynthesis under low night temperature（8°C） stress in peanuts were studied in order to find out the appropriate concentration of Ca2＋through the artificial climate chamber potted culture test.The results indicated that Ca2＋,by means of improving the stomatal conductivity of peanut leaves under low night temperature stress,may mitigate the decline of photosynthetic rate in the peanut leaves.The regulation with 15 mmol L-1CaCl 2（Ca15） was the most effective,compared with other treatments.Subsequently,the improvement of Ca2＋on peanut photosynthesis under low night temperature stress was validated further through spraying with Ca15,Ca2＋chelator（ethylene glycol bis（2-aminoethyl） tetraacetic acid; EGTA） and calmodulin antagonists（trifluonerazine; TFP）.And CaM（Ca2＋-modulin） played an important role in the nutritional signal transduction for Ca2＋mitigating photosynthesis limitations in peanuts under low night temperature stress.