多环芳烃在茶树鲜叶及绿茶加工过程中残留水平研究

利用气相色谱-串联质谱联用仪监测了茶树鲜叶及其绿茶加工中多环芳烃(PAHs)的残留水平。结果表明,不同地区茶树一芽二叶样品PAHs含量差异明显,产地环境PAHs污染程度对茶鲜叶PAHs含量影响较大。茶芽、嫩叶、老叶PAHs含量分别在40.5~52.8μg·kg~(-1)、50.0~67.4μg·kg~(-1)和91.5~97.6μg·kg~(-1)之间,PAHs含量大小顺序为老叶嫩叶芽。汽车尾气对交通公路旁茶树芽和嫩叶PAHs含量影响较大,且对50 m范围内茶树鲜叶影响更明显。电加热干燥模式下,水分散失和PAHs挥发是影响绿茶加工过程中PAHs含量的两个关键因子。加工环节过后,茶叶PAHs含量由61.0μg·kg~(-1)上升到166.1μg·kg~(-1)。摊放和干燥过程中PAHs大量挥发,造成茶叶干重中PAHs残留量由292.0μg·kg~(-1)降低到171.9μg·kg~(-1)。     

近红外光谱分析技术应用于植物叶片研究综述

近红外光谱技术（Near Infrared Spectroscopy，NIRS）作为 20 世纪 80 年代后期迅速发展起来 的一项检测技术，已被广泛应用于许多植物的各个组织和各种成分的分析。文章综述了该技术在植物叶 片研究上的应用进展，包括基于叶片特征的植物种类鉴别、植物叶片病虫害诊断、育种材料选择、叶片 内含物质含量测定等 4 个方面，并对近红外光谱检测技术的应用于植物叶片研究前景进行了展望。     

海南岛西部橡胶人工林冠层温度变化及其与微气象要素的关系

冠层温度是表征植物生理生态过程及能量平衡状况的重要参数之一。为探讨热带森林冠层温度在不同时间尺度下的变化规律并且初步分析环境因素与冠层温度的关系,本研究利用红外温度传感器测定了海南岛西部橡胶人工林2017年全年的冠层温度数据以及同步得到的冠层微气象资料,对干季和湿季下海南岛西部橡胶人工林冠层温度（T_c）与大气温度（T_a）特征进行了分析,同时结合微气象因子进行了讨论。结果表明：橡胶人工林冠层温度全年各月日变化都为单峰曲线,相比T_a,T_c具有明显的位相前移、变化加剧的特点。白天林冠边界层处于不稳定状态,林冠为土壤-植物-大气连续体（Soil-Plant-Atmosphere Continuum,SPAC）的热源;夜晚林冠边界层为逆温层结,呈稳定状态,林冠为SPAC的冷源。湿季冠层温度高于干季。若仅考虑T_a,T_c与T_a之间具有很好的线性关系,其线性方程为T_c= 1.033T_a-0.656;若同时考虑大气温度（T_a）、净辐射（R_n）、相对湿度（RH）与风速（V）等微气象因子,其复相关系数表明全年均呈极显著相关,偏相关系数表明干季冠层温度变化主要受T_a、R_n和RH的影响,其次受V的影响;湿季主要受T_a与RH的共同作用,R_n与V对其的影响相比可忽略不计。此研究结果初步揭示了橡胶人工林冠层温度的全年变化规律及其与众多微气象因子之间的关系,为进一步探究冠层温度变化及其影响机制提供科学依据。     

连翘叶精油微胶囊制备工艺优化及其对油脂抗氧化的影响

为探索制备连翘叶精油微胶囊的工艺条件及其对油脂的抗氧化效果，以包埋率为评价指标，在单因素试验的基础上，采用响应面法对连翘叶精油微胶囊的工艺条件进行了优化，同时采用测定过氧化值（POV）、脂肪氧化程度值（TBARS）的方法探索了微胶囊对油脂的抗氧化能力。结果表明，连翘叶精油微胶囊的最佳工艺参数为：壁芯比8∶1（g/mL），包埋温度60 ℃，包埋时间2.3 h，包埋功率400 W，在此条件下连翘叶精油微胶囊包埋率可达44%。油脂抗氧化研究结果表明，微胶囊组ML（0.20 g）、MM（0.10 g）、MS（0.05 g）的POV值高于阳性对照组（VC），但明显低于空白对照组；微胶囊ML、MM、MS三组的TBARS值低于空白对照组，且随着连翘叶精油微胶囊用量的增大，其对油脂氧化的抑制作用逐渐增强。     

榆林市风沙区杨树叶和松针不同生长期营养成分分析

由于大部分养殖户或养殖场对杨树叶和松针可以作为饲料原料来合理利用的了解甚少,以致于榆林市杨树及松针资源在饲料行业上的应用还不是很广泛。笔者通过对榆阳区西北风沙区2007年4、7、9、10月份(生长初期—落叶期)杨树叶和松针的主要营养成分进行测定,并对比分析,结果表明:两样本的粗纤维随生长的进行均呈明显上升趋势,而粗蛋白则均呈明显下降趋势,但粗脂肪、粗灰分、钙、磷、有机物、无氮浸出物等成分均无明显规律性。同时,杨树叶在生长的过程中粗蛋白、粗纤维含量变化趋势明显,而松针的则变化相对平稳。通过笔者的研究可以为榆林市开发杨树和松针资源作为饲料原料来利用提供一些有用的数据,并就杨树叶和松针做为榆林节粮饲料原料的利用方法上提一些建议供参考。     

Mapping and validation of the quantitative trait loci for leaf stay‐green‐associated parameters in maize

Functional stay‐green is generally regarded as a desirable trait of varieties in major crops including maize. In this study, we used an F_3:4 recombinant inbred line population with 165 lines from a cross between a stay‐green inbred line (Zheng58) and a model inbred line (B73) using 211 polymorphic simple sequence repeat markers to map quantitative trait loci for three stay‐green‐associated parameters, chlorophyll content, photosystem II photochemical efficiency and stay‐green area, at maturity stage, detected a total of 23 quantitative trait loci (QTL) on nine chromosomes. Single QTL explained 3.7–13.5% of the phenotypic variance. Additionally, we validated some important stay‐green QTL using a heterogeneous inbred family approach and found that the stay‐green‐associated parameters were significantly correlated with the plant yield. This study may contribute to a better insight into the regulatory mechanism behind leaf stay‐green in maize and a novel development of elite maize varieties with delayed leaf senescence through molecular marker‐assisted selection.     

Estimation of urban tree canopy cover using random point sampling and remote sensing methods

Trees play an important role in urban areas by improving air quality, mitigating urban heat islands, reducing stormwater runoff and providing biodiversity habitat. Accurate and up-to-date estimation of urban tree canopy cover (UTC) is a basic need for the management of green spaces in cities, providing a metric from which variation can be understood, change monitored and areas prioritised. Random point sampling methods, such as i-Tree canopy, provide a cheap and quick estimation of UTC for a large area. Remote sensing methods using airborne Light Detection And Ranging (LiDAR) and multi-spectral images produce accurate UTC maps, although greater processing time and technical skills are required. In this paper, random point sampling and remote sensing methods are used to estimate UTC in Williamstown, a suburb of Melbourne, Australia. High resolution multi-spectral satellite images fused with LiDAR data with pixel-level accuracy are employed to produce the UTC map. The UTC is also estimated by categorising random points (a) automatically using the LiDAR derived UTC map and (b) manually using Google Maps and i-Tree canopy software. There was a minimum 1% difference between UTC estimated from the map derived from remotely sensed data and only 1000 random points automatically categorised by that same map, indicating the level of error associated with a random sampling approach. The difference between UTC estimated by remote sensing and manually categorised random point sampling varied in range of 4.5% using a confidence level of 95%. As monitoring of urban forest canopy becomes an increasing priority, the uncertainties associated with different UTC estimates should be considered when tracking change or comparing different areas using different methods.     

Effect of Different Concentrate-roughage Ratios on Rumen Degradability of Cassava Stems and Leaves Total Mixed Ration in Goat

The rumen degradations of TMR were studied in this experiment,in which cassava stems and leaves were used as roughage and formulated with concentrate in different proportions.The purpose of this study was to formulate the available TMR for finishing goat,and provide a theoretical basis for the applications of cassava stems and leaves in goat production.Six Hainan Black goats with permanent rumen fistulas were selected,the rumen degradabilities of DM,CP,NDF and ADF of TMR with 6 different concentrate to forage ratio（2:8,3:7,4:6,5:5,6:4 and 7:3）were tested using nylon bag method.The results showed that,the DM effective degradabilities at the ratio of 4:6,5:5,6:4,7:3 were significantly higher than that of 2:8 and 3:7（P<0.05).CP effective degradabilities at the ratio of 2:8,3:7,4:6 were significantly higher than that of 5:5,6:4 and 7:3（P<0.05).The NDF effective degradation at the ratio of 5:5 was significantly higher than that in the other groups（P<0.05).The ADF degradation at the ratio of 3:7 was significantly higher than that of 4:6,5:5, 6:4 and 7:3（P<0.05).The results indicated that,the nutrient degradation in rumen were higher when the concentrate to forage（cassava stems and leaves）ratio in TMR were 3:7,4:6 and 5:5,and the recommended ratio range were 4:6 to 5:5 in production practice.     

高产高效栽培下春玉米生育后期冠层结构及其光合特性的研究

以郑单958为供试品种，设高产高效栽培(GCGX)和农户传统栽培(CK)2个处理，于2012年和2013年连续2 a进行田间试验，测定春玉米生育后期冠层结构及其光合特性的变化规律。结果表明：吐丝期和乳熟期株高、穗位高产高效栽培略高于农户传统栽培。与农户传统栽培相比，高产高效栽培春玉米叶面积指数较大，在生育期上表现为吐丝之后更为明显，在叶位上表现为棒三叶以下叶片最为突出；不同叶位的叶倾角高产高效栽培显著小于农户传统栽培，而叶向值均显著大于农户传统栽培，在棒三叶表现最为明显；高产高效栽培生育后期净光合速率显著高于农户传统栽培，冠层光合能力极显著高于农户传统栽培。高产高效栽培下春玉米产量为14.009 t·hm^-2(2012)和13.255 t·hm^-2(2013)，均极显著高于农户传统栽培。     

夹竹桃叶提取液对红蜡蚧若虫防治效果的研究

为了解夹竹桃叶提取液对红蜡蚧若虫的防治效果,以无氯清水和95%乙醇为溶剂,提取得到夹竹桃叶水提液和夹竹桃叶醇提液,对红蜡蚧初孵若虫涌散期的防治效果进行初步研究。结果表明:夹竹桃叶提取液对红蜡蚧初孵若虫有较好的防治效果,随着提取液浓度的增加,防治效果增强;随着处理时间的延长,死亡率上升。夹竹桃叶水提液1∶10、夹竹桃叶醇提液1∶10浓度配比的防治效果最好。