化学脱叶对桃自然休眠的调控效应

以两年生曙光油桃为试材,研究不同时期不同化学物质的脱叶效果和打破休眠的效应,结果表明:8%NH4NO3的脱叶效果最好,但对树体有严重药害,综合考虑以8%尿素为优选脱叶试剂;化学脱叶使萌芽提早6~8d,但仅使花期提前2~4d日对叶芽的作用效果显著;化学脱叶明显降低了花芽碳水化合物含量、自然坐果率和花粉生活力,使花期延长,但对完全花比例无显著影响。     

施肥和刈割日期对杂交狼尾草钙、磷、镁含量的影响及其与家畜需要的关系

研究了不同施肥处理和刈割日期对杂交狼尾草Ca、P和Mg含量的影响及其与家畜营养的关系,结果表明,有机肥的施用显著降低了植株Ca含量,对植株P和Mg含量无显著影响;随无机氮施用水平的提高,杂交狼尾草植株Ca和Mg含量显著提高,P含量显著降低;植株Ca、Mg含量均随刈割日期的推迟而显著提高,植株磷含量随刈割日期的推迟呈先降后升的规律;根据NRC推荐的饲养标准(奶牛、肉牛和绵羊),所有处理杂交狼尾草植株Mg含量均能满足家畜的需要,Ca:P为(0.95～2.67):1;利用杂交狼尾草饲喂高产奶牛时,应注意日粮中Ca、P的添加.     

Effect of forest structure and health on the relative surface temperature captured by airborne thermal imagery – Case study in Norway Spruce-dominated stands in Southern Finland

The effect of forest structure and health on the relative surface temperature captured by airborne thermal imagery was investigated in Norway Spruce-dominated stands in Southern Finland. Airborne thermal imagery, airborne scanning light detection and ranging (LiDAR) data and 92 field-measured sample plots were acquired at the area of interest. The surface temperature correlated most negatively with the logarithm of stem volume, Lorey’s height and the logarithm of basal area at a resolution of 254?m² (9?m radius). LiDAR-derived metrics: the standard deviations of the canopy heights, canopy height (upper percentiles and maximum height) and canopy cover percentage were most strongly negatively correlated with the surface temperature. Although forest structure has an effect on the detected surface temperature, higher temperatures were detected in severely defoliated canopies and the difference was statistically significant. We also found that the surface temperature differences between the segmented canopy and the entire plot were greater in the defoliated plots, indicating that thermal images may also provide some additional information for classifying forests health status. Based on our results, the effects of forest structure on the surface temperature captured by airborne thermal imagery should be taken into account when developing forest health mapping applications using thermal imagery.     

新疆机采棉花实现叶片快速脱落需要的温度条件

随着机采棉的快速推进,籽棉含杂率过高导致清理工序过多及纤维不必要的损伤。新疆棉区棉花生长后期的热量资源有限,如何合理喷施脱叶催熟剂是改善原棉品质的关键技术措施。本研究采用分期喷施脱叶催熟剂的方式,探讨了温度变化对棉花叶片脱落率的影响及实现棉花叶片快速脱落需要的温度条件。结果表明,在喷施脱叶催熟剂后(7.0±1.0)d内,棉花叶片脱落率最高,达55%～79%,且与最高温度和每日≥12°C有效积温呈显著的线性关系。若要在喷施脱叶催熟剂后(7.0±1.0)d内实现>55%的叶片脱落率,则应满足该时间段最高温度大于27.2°C、每日≥12°C有效积温大于7.0°C·日的要求。因此,喷施脱叶催熟剂后(7.0±1.0) d内是实现良好脱叶效果的关键时间段,期间的最高温度和每日≥12°C有效积温则是影响的关键因素。     

梨ERF超家族全基因组鉴定及表达分析

中国南方地区普遍存在的由于干旱等原因提早落叶导致的梨二次花现象给生产带来了很大的损失,且该过程可以通过人工摘叶处理进行模拟诱导。乙烯响应因子ERF成员被认为参与了植物的激素应答、生物和非生物胁迫以及生长发育调控过程。本研究基于公开的白梨基因组序列,利用生物信息学方法对其中的ERF因子进行鉴定,并对其分组及各组结构域进行了详细分析。结合课题组采用摘叶诱导二次花形成过程中的梨转录组数据,分析了响应该过程的ERF成员。结果表明,共获得了 211个白梨ERF家族编码基因,并可根据系统进化关系和结构域保守性分为11个组,其中种特有组一个。砂梨摘叶诱导二次花过程的转录组数据分析表明,有37个ERF因子差异表达,摘叶初期(摘叶后7 d)无响应,中期(摘叶后17 d)以下调表达为主,后期上调。对其中的4个差异表达基因进行了实时荧光定量PCR分析验证,结果与转录组分析结果吻合。此研究进一步丰富了梨响应胁迫反应的ERF基因资源,为进一步探讨ERF在成花过程中的作用提供了理论依据。     

枇杷属植物落黄叶片颜色遗传多样性分析

调查发现枇杷属(Eriobotrya)植物种质落黄叶片有红褐色、金黄色、紫红色等24种代表性色泽。通过便携式色差仪观测枇杷属10个种176份种质落黄叶片正面和背面的色泽参数,探讨落黄叶片颜色的遗传多样性特征。结果表明:(1)枇杷属植物落黄叶片正面和背面的色泽参数L、a、b值变异系数差异较大,变幅为8.65%~185.30%,Shannon’s遗传多样性指数为1.95,说明落黄叶片色泽变异多样;(2)不同种质类群间和不同来源地类群间的变异系数和Shannon’s遗传多样性指数差异均较明显,呈现出栽培驯化程度越高,落黄叶片正面和背面的b值变异系数越小和a值变异系数越大的趋势;云南、贵州、福建地区的类群多样性指数较高;(3)系统聚类将落黄叶片正面色泽划分成12组,背面分成10组,且各组内所包含的枇杷种质类型差异大;(4)L值、b值对落黄叶片正面和背面的系统聚类分析贡献率均较大,落黄叶片正面L值与背面b值呈极显著正相关;(5)落黄叶片颜色的遗传多样性可作为枇杷属植物形态学特征描述的补充,为枇杷属植物的鉴别和利用提供新的参考,对枇杷分类研究具有潜在价值。     

川西高原苹果早期落叶病调查及防治研究

[目的]探讨川西高原苹果早期落叶病发生规律及药剂防治效果。[方法]于2009～2011年对川西高原苹果早期落叶病进行了系统调查,并对其进行了不同药剂、不同施药时期的防治效果研究。[结果]病原种类以褐斑病为主,占32.5%;灰斑病占29.9%;轮斑病占25.7%。田间消长规律：一般从5月中旬发生为害至10月上中旬结束,但终年只有1个发病为害高峰,且其消长与雨量呈正相关（R2=0.891 8＊＊）。药剂防治试验表明40%福星防效最好（86.5%）,且花后施药1次为佳。[结论]为苹果早期落叶病的有效防治提供了理论依据。     

南方早熟梨异常落叶的原因及防控技术

介绍了南方早熟梨异常落叶的发生特点及原因,提出强化果园肥水管理、加强病虫害综合防治、合理整形修剪、适量挂果与分批采收等栽培管理措施.     

Specific polyphenol oxidase activity of red clover (Trifolium pratense) and its relation with forage quality in field experiments

Abstract

In feeding studies, red clover (RC) influenced positively the N utilization by ruminants. A relationship between polyphenol oxidase (PPO) activity and forage quality has not been established. Our objective was to investigate seasonal, site, genotype, and management effects on specific PPO activity in RC in three experiments under field conditions, and relate the activity to forage-quality parameters. In Experiment 1, six RC genotypes at two study sites were submitted to a 3-cut system. Specific PPO activity, forage quality, and vegetation stage were determined. PPO activity varied between harvest and study sites, with genotypes differing up to 3-fold in PPO activity within harvests. The specific PPO activity, forage quality, and vegetation stage in RC subjected to 5-cut system and grazing (Experiment 2) were determined. Additionally, in Experiment 3, cutting frequency in RC swards including mechanical stress (rolling) was investigated. The induction of PPO activity in RC by grazing or mechanical stress (Experiments 2 and 3) increased the activity up to 2.5-fold compared with RC at similar vegetation stage submitted to the 5-cut system. Mechanical stress induced by grazing or rolling, and seasonal differences, seem to have a larger influence on specific PPO activity than does the genotype effect observed in Experiment 1. For forage quality, an increased specific PPO activity explained 29–46% of the reduction in protein fraction ‘A’ content (non-protein N) in the cutting systems in Experiments 2 and 3. Other CP fractions achieved a lower relation. Furthermore, the precipitation-to-temperature ratio preceeding a harvest explained 63% of the variation in the specific PPO activity. In conclusion, the PPO activity in RC is induced by grazing and rolling. Whereas weather conditions preceeding a harvest showed a large influence, genotype influence had only minor relevance. These results may have implications for regional harvest management towards efficient N utilization by ruminants.     

刚竹毒蛾虫情级的研究

通过对刚竹毒蛾空间分布和各代食叶量调查及不同危害程度与毛竹产量关系分析，结合近20a测报和防治工作经验，提出了以20％食叶量为起始防治指标，以20％～50％，51％～70％。71％以上为预测轻、中、重3级指标。以10％食叶量为累进指标，进一步将虫情级分为10级。并对调查时间、调查方法进行综述。