牛耳朵无土栽培基质的优化筛选

以牛耳朵为试材,泥炭、蛭石、珍珠岩、河沙、炉渣为栽培基质材料,选用HoaglandArnon全营养液浇灌,进行无土栽培试验。采用完全随机设计方法,研究了22种基质配方对牛耳朵生长及开花的影响,以期筛选出适合牛耳朵生长的无土栽培基质。结果表明:牛耳朵无土栽培基质以处理T21(泥炭+蛭石+珍珠岩=1∶1∶1)最佳,其次为处理T12(河沙)、T20(泥炭+蛭石+珍珠岩=3∶1∶1)。     

农杆菌介导的朝鲜碱茅PuP5CS基因转化紫花苜蓿的研究

为提高紫花苜蓿(Medicago sativa)的抗逆性,利用在朝鲜碱茅(Puccinellia chinampoensis)已克隆的Pu P5CS基因成功构建了p CAMBIA3300-Pu P5CS表达载体,以子叶为外植体,通过农杆菌介导共培养法转化紫花苜蓿"公农5号"(M.sativa cv.Gongnong No.5),并以2.0 mg·L-1的草铵膦进行筛选,抗性愈伤组织诱导率为22.4%,经草铵膦筛选的植株进行PCR检测和RT-PCR检测。结果显示,共获得11株转化植株,表明Pu P5CS基因已转入T0紫花苜蓿植株,且能够在RNA水平上正常表达。     

Effects of insect infestation on rodent‐mediated dispersal of Quercus aliena: results from field and enclosure experiments

Rodents influence plant establishment and regeneration by functioning as both seed predators and dispersers. However, these rodent–plant interactions can vary significantly due to various environmental conditions and the activity of other insect seed predators. Here, we use a combination of both field and enclosure (i.e. individual cage and semi‐natural enclosure) experiments, to determine whether rodents can distinguish sound seeds from those infested with insects. We also demonstrate how such responses to insects are influenced by food abundance and other environmental factors. We presented rodents with 2 kinds of Quercus aliena seeds (sound and insect‐infested seeds) in a subtropical forest in the Qinling Mountains, central China, from September to November of 2011 to 2013. The results showed that rodents preferred to hoard and eat sound seeds than infested seeds in the field and semi‐natural enclosure, while they preferred to eat infested seeds over sound seeds in the individual cages. In addition, both hoarding and eating decisions were influenced by food abundance. Rodents hoarded more sound seeds in years of high food abundance while they consumed more acorns in years of food shortage. Compared with field results, rodents reduced scatter‐hoarding behavior in semi‐natural enclosures and ate more insect‐infested seeds in smaller individual cages. These results further confirm that rodents distinguish infested seeds from non‐infested seeds but demonstrate that this behavior varies with conditions (i.e. environment and food abundance). We suggest that such interactions will influence the dispersal and natural regeneration of seeds as well as predation rates on insect larvae.     

北京郊区散养鸡及鸡蛋沙门氏菌带菌情况调查

目的：和方法采用菌落PCR法和细菌培养法调查北京郊区三个散养鸡场的鸡蛋和鸡粪样沙门氏菌的带菌情况,并对两种方法的检测结果进行比较。结果 PCR检测结果表明北京郊区散养鸡粪便沙门氏菌平均阳性率90.87%,蛋内沙门氏菌平均阳性率40%;细菌培养结果表明散养鸡鸡粪平均沙门氏菌阳性率82.3%,蛋沙门氏菌平均阳性率33.3%。结论与传统细菌培养方法相比,菌落PCR法在数值上可提高散养鸡鸡粪和鸡蛋沙门氏菌检出率。     

三菌混合固态发酵苹果渣产复合酶的研究

利用实验室保藏的多株菌种,对苹果渣进行三元混菌固态发酵产复合酶。以纤维素酶、木聚糖酶、果胶酶活性大小为测定指标,对筛选出单菌活性较高的菌株,按照1:1:1进行3种菌混合发酵,确定混菌后效果较好的3种菌。考虑到试验因素之间的交互作用,以3种菌的接种比例及接种时间间隔作为试验因素,通过正交表交互作用设计试验及分析,确定3种菌混合活性最佳时间间隔为菌种#1、#2、#3同时接种;接种#1体积1ml、接种#2体积2ml、接种#3体积1ml。混菌后酶活性比3种单菌的酶活分别提高了10.9%、2%、20%,达到了优化的目的。     

不同油茶饼粕的营养成分比较与饲用可行性分析

为了研究不同制油工艺对油茶饼粕的营养成分、氨基酸均衡性及蛋白质变性程度的影响,以油茶果皮作对照,采用凯氏定氮法与恒重法,测定了油茶饼粕的主要营养成分的含量,并采用氨基酸评分模式评价了油茶饼粕中氨基酸的营养价值.结果表明:就粗蛋白含量而言,油茶果壳的最低(3.69%),冷榨粕的最高(13.00%);氨基酸总含量较高,最高...     

苏打盐碱胁迫下不同来源苜蓿品种抗盐性综合评价

\t\t\t\t\t目的 \t\t\t\t\t探究不同浓度ABA对苏打盐碱胁迫下紫花苜蓿幼苗生理效应的影响。\t\t\t\t\t\t\t\t\t\t\t\t\t方法 \t\t\t\t\t以WL343HQ紫花苜蓿为试验材料,对其幼苗进行150 mmol/L苏打盐碱胁迫和不同浓度的ABA缓解处理,测定不同处理幼苗叶片的生理生化变化,采用隶属函数法对ABA缓解效应进行综合分析。\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t苏打盐碱胁迫紫花苜蓿幼苗喷施ABA后,紫花苜蓿叶片的可溶性糖、甜菜碱、脯氨酸、可溶性蛋白含量以及POD、PAL、CAT、AXP活性均随着ABA浓度的增加呈现先增后降的趋势,4种渗透调节物质和4种抗氧化酶活性在ABA浓度为50或100 μmol/L 时达最大值。\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t通过隶属函数值综合分析,在ABA浓度为25~100 μmol/L 时对苏打盐碱胁迫均有一定缓解作用,且在ABA浓度为50~75 μmol/L 时对苏打盐害缓解效果最佳。\t\t\t\t     

决策树在精准农业中的应用现状与发展趋势

决策树算法是一种重要的分类方法,是数据挖掘领域研究热点之一.现介绍了决策树算法当前的研究状况.从土壤质量等级划分、自然灾害分析、遥感影像分类及耕地质量分析等方面介绍决策树算法在精准农业中的应用现状,对决策树算法在精准农业中的应用前景进行了展望.     

钙在橄榄树器官中的定量研究

本研究用原子吸收光谱法分析了果园土壤及橄榄树体各器官中钙量和不同组分钙的含量。结果表明：0～30cm土层中钙含量最高为0．65mg／g。橄榄器官中叶的钙含量最高为4．523mg／g，其次为根、果、结果枝。地上部器官钙含量由主干一主枝一结果枝一叶片逐渐增加。在各器官中钙主要以醋酸溶钙和盐酸溶钙的形式存在。