Coincidence of maximum severity of powdery mildew on grape leaves and the carbohydrate sink‐to‐source transition

Grapevine leaves infected with powdery mildew are a source of inoculum for fruit infection. Leaves emerging on a single primary shoot of Vitis vinifera cv. Cabernet Sauvignon were exposed to average glasshouse temperatures of 18°C (0·23 leaves emerging/day) or 25°C (0·54 leaves emerging/day). All leaves on 8–10 shoots with approximately 20 leaves each were inoculated with Erysiphe necator conidia to assess disease severity after 14 days in the 25°C glasshouse. Two photosynthetic ‘source’ leaves per shoot on the remaining 8–10 shoots were treated with ¹⁴CO₂ to identify, by autoradiography, the leaf position completing the carbohydrate sink‐to‐source transition. There was a clear association between the mean modal leaf position for maximum severity of powdery mildew (position 3·7 for 18°C; position 4·4 for 25°C) and the mean position of the leaf completing the sink‐to‐source transition (position 3·8 for 18°C; position 4·7 for 25°C). The mean modal leaf position for the maximum percentage of conidia germinating to form secondary hyphae was 4·2 for additional plants grown in the 25°C glasshouse. A higher rate of leaf emergence resulted in a greater proportion of diseased leaves per shoot. A Bayesian model, consisting of component models for disease severity and leaf ontogenic resistance, had parameters representing the rate and magnitude of pathogen colonization that differed for shoots developing in different preinoculation environments. The results support the hypothesis that the population of leaves in a vineyard capable of supporting substantial pathogen colonization will vary according to conditions for shoot development.     

Effects of boron and lime on boron concentration and growth of forage legumes under greenhouse conditions

Abstract

Maximum yields of red clover, alfalfa, and birdsfoot trefoil were obtained when 0.25 to 1.0 ppm B was added to the soil. An application of lime to raise the soil pH to 5.8–6.3 improved yields, while at pH 6.8 a decline in yield in the first and second cuts of birdsfoot trefoil was noted. There was a marked B x lime interaction on the yield of all cuts of birdsfoot trefoil and first cut of red clover, with much higher yields with high rates of lime at high rates of added B.

Levels of 4 to 9 ppm B in the leaf tissue of the three crops were in the deficiency range. Boron concentrations of 21 to 45, 39 to 52, and 30 to 45 ppm in the first cuts of red clover, alfalfa, and birdsfoot trefoil were indicative of sufficiency and were associated with maximum yields, while levels of >59, >99, and >68 ppm, respectively, in the three crops were in the toxicity range. Sufficiency levels of soil B for legumes appeared to be related to pH since B deficiency was more severe at higher pH than at lower pH. Liming of soil from pH 5.3 to 6.8 resulted in decreased concentration of B in all the three crops with the smallest decreases in alfalfa. There was a marked B x lime interaction on the B concentrations of the three crops, with much higher B concentrations in high B treatments at low soil pH than at high pH values.     

鲐鱼软骨糖胺聚糖的硫酸软骨素的结构及其与生长因子的相互作用

为了开发具有药用价值的硫酸软骨素(chondroitin sulfate,CS)的新资源,从鲐鱼(Pneumatophorus japonicus Houttuyn)软骨蛋白聚糖(proteoglycan,PG)制备了糖胺聚糖(glycosaminoglycan,GAG),用酶降解和阴离子交换HPLC法测定了GAG的CS的组成及其含量,用凝胶层析法测定了GAG的分子量,用表面等离子体谐振(surface plasmon resonance,SPR)法测定了其与多效生长因子(PTN)、中期因子(MK)和肝细胞生长因子(HGF)相互作用的动力学参数结合速率常数(ka)、解离速率常数(kd)和平衡解离常数(KD)。结果显示,鲐鱼软骨GAG含量约为651μg/mgPG或1.09μmol/mgPG(按照二糖单位计算),主要含CS(1.03μmol/mgPG,按照二糖单位计算),CS酶解产生的主要二糖单位是ΔDi-6S(38.8%)和ΔDi-4S(46.3%),有少量的ΔDi-0S(8.4%)和ΔDi-diSD(6.5%)。GAG(CS)的分子量为78kD。GAG(CS)与生长因子的相互作用的动力学参数ka((mol/L)-1.s-1)、kd(s-1)和KD(nmol/L)分别为(2.77±0.17)×105、(7.74±1.56)×10-5和(0.28±0.06)(MK),(1.05±0.22)×104、(4.16±0.80)×10-3和(417±131.3)(PTN),(7.04±0.94)×105、(7.84±2.82)×10-3和(11.1±3.80)(HGF)。该GAG同MK、HGF和PTN有高的或较高的亲和性,暗示鲐鱼软骨GAG的CS有可能通过调节生长因子的信号转导途径而对某些疾病发挥治疗作用,具有潜在进一步药用开发价值。     

氮磷钾配施对花生产量的影响及效应分析研究

为探寻大花生新品种‘青花7号’的最佳施肥方案,采用三因素二次回归通用旋转组合设计方法,建立了氮、磷、钾施肥量与产量关系的效应方程。通过对回归方程的检验及效应分析,探讨了氮、磷、钾肥的单因子效应、互作效应和最佳施肥量。结果表明,施氮、磷、钾肥对花生产量具有明显的增产作用,其肥料效应顺序为钾肥>磷肥>氮肥;氮磷互作对花生产量的影响为极显著。对于试验地块种植的花生新品种‘青花7号’获得高产的最佳施肥组合为：氮肥106.08~133.92 kg/hm²,磷肥159.12~200.88 kg/hm²,钾肥为138.28~161.72 kg/hm²。     

GGE双标图对抗寒烤烟品种区域试验的分析

利用2012年南平市抗寒烤烟品种区域试验中各品种在3个不同试验点上的平均产量和平均产值,经过环境中心化后的数据,以GGE双标图的图谱形式阐述了参试品种在各试验点的表现、各试验点环境间关系、各试验点的区分力和代表性及各参试品种平均表现和稳定性。结果表明：（1）‘CB-1’在延平试验点平均产量、平均产值最高,‘NF-1’在邵武、浦城试验点平均产值最高;（2）邵武和浦城试验点之间存在紧密正相关,且与延平试验点均表现为负相关;（3）延平、浦城、邵武各试验点对参试品种均具有较强的区分能力,作为抗寒品种筛选的试验点,浦城和邵武具有较强代表性;（4）5个参试品种中‘NF-2’表现既高产量、高产值又稳定的品系,‘NF-1’表现相对高产和稳定的品系。     

虚拟变电站设计交互技术研究

通过对沈阳市供电公司东陵分公司上伯关变电站真实模拟,构建虚拟变电站系统。利用VRP虚拟现实平台实现变电站虚拟自由漫游,用户可以自行选择漫游模式。对VRP-SDK的二次开发设置脚本触发,可进行操作漫游及根据实际需求对系统中可控的电气元件进行虚拟操作,实现系统的培训功能。     

Kriging方法在地下水风险评价中的改进与应用

地下水与地表水系统的交互影响在环境管理中的重要性日益凸显。其中,准确、快捷地估算水力渗透系数是科学管理的关键。但是,在环境规划与管理中,管理者所研究的尺度一般较大,在十几甚至几十平方千米的范围里面,传统的Kriging方法显得过于复杂,实用性大大降低。该研究在更加注重简单性与实用性原则的前提下,对Kriging方法进行了简化,并以此评价地下水的风险系数。      

小管出流灌溉条件下水肥耦合对树莓生长和产量的影响

在田间利用防雨棚和测坑设施进行了水肥耦合对树莓生长、产量影响的试验研究,试验运用二因素五水平回归正交组合设计,建立了树莓产量的水肥耦合数学模型。结果表明:在现蕾期和花期,中水平的土壤含水量和中水平的施肥量(土壤含水量控制在下限26.2%,施肥量270kg/hm2)有利于植株生长;在结果期,较高的土壤含水量和施肥量(土壤含水量控制在31.9%以上,施肥量460.95kg/hm2)有利于树莓植株的生长。当土壤含水量控制在28.25%以上、施肥量为460.95kg/hm2时,产量达到最大值(19 169.25kg/hm2)。     

四种水稻蛋白与水稻黑条矮缩病毒编码非结构蛋白P7-2的互作分析

水稻黑条矮缩病毒(RBSDV)是斐济病毒属的成员之一,可侵染玉米和水稻等作物,给亚洲地区的田间生产带来严重的损失。RBSDV有10条双链RNA(double strand RNA, dsRNA)基因组,编码12个蛋白。其中6个蛋白是病毒粒子的结构成分(P1,P2,P3,P4,P8,P10),6个非结构蛋白分别为P5,P6,P7\|1,P7\|2,P9\|1,P9\|2。在非结构蛋白中,P5,P6和P9\|1已被证实参与形成毒质结构,P7\|1被认为可在细胞质中形成类似管状的结构作为病毒胞间扩散的通道,P7\|2和P9\|2的功能目前尚不明确。文章采用Pull\|Down和液相色谱—质谱联用(LC\|MS/MS)等技术来鉴定水稻蛋白(日本晴)与P7\|2蛋白间可能存在的互作关系。通过Pull\|Down实验分析,发现有4种水稻蛋白可与P7\|2相结合,其中2个蛋白为转录相关蛋白,1个为氨基转移酶,还有1个为假定的分子伴侣60前体。实时荧光定量PCR分析显示,感病寄主中的转录相关蛋白和假定的分子伴侣60前体的表达量上调,而氨基转移酶的表达量降低。