Study of stomatal parameters for selection of drought resistant varieties in Triticum durum DESF

An analysis was made of the stomatal apparatus of the leaves of five Italian durum wheat varieties, grown under different natural rainfall regimes.Rainfall had a significant influence on both development of the leaves and frequency and size of the stomata. Results were examined with respect to yield stability. Correlations between examined traits were calculated.     

Genotypic differences in organogenesis from callus of ten triticale lines

Summary Callus was obtained from immature excised embryos of triticale using MS medium supplemented with 3 mg/l 2,4-D and 1 mg/l kinetin. The presence of 2,4-D was essential for continued callus proliferation. Plantlets were induced from the calli by sub-culturing on medium either devoid of auxin or containing 0.1 mg/l 2,4-D. The capacity to produce callus and to form organs and plantlets differed markedly among the genotypes used. Lines also had distinct response to presence and absence of 2,4-D in the regeneration media. The callus of most triticale lines used differentiated into organs more readily on MS medium supplemented with 0.1 mg/l 2,4-D than on medium without growth regulators. Very high frequencies (up to 75%) of plantlet regeneration were observed in several of the triticale lines studied.     

Genetic Variation for Regenerative Response in Immature Leaflet Cultures of the Cultivated Peanut,Arachis hypogaea*

Forty-seven genotypes of the cultivated peanut, Arachis hypogaea L., were screened for regenerative responses of immature leaflet cultures on two media varying in the auxin: cytokinin ratio. Statistical analysis revealed significant media and genotype differences for rhizogenesis plus media differences for callus proliferation but no differences for shoot formation. When genotypes were categorized according to botanical types, differences between subspecies were observed for rhizogenesis. Cultivars of the Virginia botanical type (subspecies hypogaea) were significantly different from either the Valencia or Spanish botanical types (both subspecies fastigiata). Overall, rhizogenesis varied from 0 to 70% among all genotypes. Shoot production was low (30%) while callus proliferation was extremely high (70%).     

阅读策略应用与英语阅读理解的相关分析

借鉴国内外应用语言学研究方法，通过问卷调查，我们对福建农林大学192名非英语专业大学一年级学生的英语阅读策略使用情况进行实证性研究，分析他们的阅读理解成绩与阅读策略使用的关系。研究结果表明：阅读理解成绩好的学生比成绩差的学生更善于选择和使用阅读策略，尤其表现在元认知策略的使用上，存在显著性差异（P=0．003）。因此认为，阅读策略的使用与学生阅读成绩存在显著的正相关关系。     

不同地区黄瓜霜霉病菌毒力的差异

为选择黄瓜抗性品种,对来自全国8个省市18个黄瓜霜霉病菌株的孢子囊长度和宽度进行研究,以期明确定黄瓜霜霉病在各地区间的差异。结果表明:18个黄瓜霜霉病菌株的孢子囊存在差异,来自同一城市的菌株间差异不显著,并从供试的10个黄瓜品种中筛选出7个对不同致病菌株反应型各异,抗病感病界限明显的品种,可初步作为黄瓜霜霉病菌生理小种分化的鉴别寄主,利用所筛选出的鉴别寄主将18个菌株分为12个致病性类型。     

Genetic variation in desiccation tolerance of Dendrobaena octaedra cocoons originating from different climatic regions

The aim of this study was to examine genetic variation in desiccation tolerance in cocoons of the parthenogenetically reproducing earthworm Dendrobaena octaedra by comparing populations originating from different geographic regions (Denmark, Norway and Finland), representing large differences in precipitation and temperature. In one experiment, the tolerance of the three populations to increasing desiccation stress in the range from 100 to 91.6% relative humidity (RH) was examined, aiming to represent ecologically relevant RH values. In a second experiment, the effect of cocoon size on desiccation tolerance was investigated at 92.3% RH in the same three populations. There were highly significant differences in desiccation tolerance between populations, indicating a high genetic differentiation of this trait in D. octaedra. Cocoons from Denmark were much more sensitive (71±14% mortality at 91.6% RH) than cocoons from Norway (21±4% mortality) and Finland (4±5% mortality). Cocoons of worms from Finland and Norway were significantly larger than cocoons produced by worms from Denmark suggesting that cocoons from Denmark lost water at a higher rate when subjected to low humidity. Assuming that slow dehydration is necessary for physiologically based protection mechanisms it may be expected that desiccation tolerance is positively correlated with cocoon size. However, within each of the populations cocoon fresh weight did not have any significant impact on desiccation tolerance. When all populations were pooled there was a significant positive effect of cocoon fresh weight on desiccation tolerance, explaining about 20% of the total variation (linear regression). It seems therefore that genetic variation of desiccation tolerance in D. octaedra cocoons is related to variation in both cocoon size and other, physiologically based tolerance mechanisms.     

河北省征地补偿标准的时空差异及其相关影响因素

为河北省征地补偿标准的修订提供借鉴依据,利用 ArcGIS 对河北省2008年和2011年各县（市）平均征地补偿标准空间分布及时间变化进行研究,并通过 SPSS 进行相关分析找出影响征地补偿标准时空变化的主要影响因子。结果表明：河北省2008年全省平均征地补偿标准为3．59万元／667m2,各县（市）平均征地补偿标准为2～4万元／667m2;2011年全省平均征地补偿标准为4．40万元／667m2,比2008年提高23％,各县（市）平均征地补偿标准为3～5万元／667m2,各县（市）平均补偿标准增长幅度集中在15．00％～30．00％。农村居民人均纯收入、地区生产总值和人口密度是征地补偿标准最重要的影响因素,总人口、常用耕地面积和参加农村医疗保险人数也对征地补偿标准具有重要影响。     

东北黑土区耕地利用效益空间差异及影响因素分析

耕地利用效益是评估区域耕地利用协调程度的必要前提,也是农业高效可持续发展的重要保障。本文以东北黑土区为研究区,依据耕地利用系统理论,构建“经济-社会-生态”效益框架,运用综合评价法、探索性数据分析法与地理探测器模型,从县域尺度分析2020年东北黑土区耕地利用效益空间差异和影响因素。结果显示：1）耕地利用综合效益、经济效益和生态效益整体上均呈现为由南部和中部平原地区向西部和北部低丘缓坡地形区减少趋势,社会效益则主要表现为由南部向北部递减的分布趋势。2）耕地利用综合效益整体上具有显著的集聚特征,高集聚主要在辽宁省南部以及北部黑龙江省县域范围分布,低集聚则集中分布在东部内蒙古和中部吉林省县域。3）从影响因素来看,黑土区耕地利用综合效益中气候、农业机械化程度和农作物复种指数是关键影响因素,且因素间的交互作用影响更加显著。为更好的提升黑土区耕地利用效益,需要把握乡村振兴协作、保护经营机制、农业综合措施和绿色技术创新等方面的促进作用,实现农业资源高效利用和可持续发展。     

灯塔站迁站气象要素差异对比及影响因素分析

为了分析灯塔迁站对气象要素的影响,通过差值统计方法,选取新站与旧站2014年1月、4月、7月、10月4个月的观测资料,对灯塔国家一般站(54348站)的气温、相对湿度、气压、风速4个气象要素的观测资料进行差值对比分析。结果表明:新站月平均气温偏低0.6~0.9℃,气压偏低0.9~1.0 h Pa,相对湿度偏高3~6个百分点,风速偏大0.7~1.4 m/s;造成气象要素差异的主要原因为城市热岛效应。     

冬小麦种质“矮孟牛”姊妹系遗传差异

采用田间试验鉴定和基因组分子标记分析相结合的方法,对冬小麦种质“矮孟牛” 7个类型的性状和基因组遗传差异比较分析。结果表明,7个类型在调查的株高、穗长、穗粒数、粒长、粒宽、单株穗数等16个性状方面存在差异,其中矮孟牛V型的主要产量构成因素等性状比较协调,总体优于其他6个类型。在检测的2 210对SSR、EST-SSR和STS标记中,有656对标记可在矮孟牛三亲本中显示多态性,将其用于矮孟牛7个类型全基因组遗传差异分析,并利用GGT2.0绘制7个类型的遗传差异图谱。在矮孟牛V型的1A、1B、2D、3A、4D、7A染色体上检测到8个特异位点,利用矮丰3号/牛朱特和孟县201/牛朱特构建的2个F₂分离群体,经IciMappingV3.0单标记QTL作图分析,发现矮孟牛V型部分特异位点附近存在与产量构成因素等重要性状相关的QTL。矮孟牛V型的基因组特异位点可能是它作为骨干亲本区别于其他姊妹系的重要基因组特征。