荔枝农药残留的初步调查

本文对广东省一些荔枝园进行抽样调查,结果初步显示按常规方式生产的荔枝有三氯杀螨醇、氯氰菊酯以及甲胺磷农药残留,而经权威认证机构认证的有机荔枝园生产的有机荔枝未检测出农药残留。有机荔枝的出现解决了食品安全问题,是未来荔枝市场发展的必然趋势。     

Physiological basis for antagonism induced by mixtures of quizalofop-ethyl and bromoxynil in maize (Zea mays)

In this study, the physiological basis for antagonism induced by mixtures of quizalofop‐ethyl and bromoxynil was investigated in maize seedlings. In sequential applications, antagonism was observed when bromoxynil was applied before quizalofop‐ethyl or in a mixture with quizalofop‐ethyl, but was minimal when bromoxynil was applied afterwards. The degree of antagonism differed with application rates of bromoxynil and with the timing of the treatment. When test herbicides were applied locally to the second leaf, the inhibition of photosystem II (PS‐II) in the herbicide‐treated leaf was higher with the mixture than with bromoxynil or quizalofop‐ethyl alone. Subsequent growth of the untreated third leaf inhibited by quizalofop‐ethyl alone then recovered, depending on the dose of bromoxynil. There was no evidence that bromoxynil affected absorption of quizalofop‐ethyl. In local applications at different positions on the second leaf, antagonism was only observed when quizalofop‐ethyl was applied to the distal part of the leaf and bromoxynil applied to the proximal part. The antagonism of bromoxynil + quizalofop‐ethyl did not occur at the level of acetyl CoA carboxylase and Hill reaction, as revealed by in vitro assays. These results suggest that bromoxynil inhibits the phloem transport of quizalofop‐ethyl and thus antagonises its whole‐plant activity in maize.     

大穗看麦娘化学防控田间效果评价

大穗看麦娘在欧洲是一种分布广泛、危害巨大的禾本科杂草,在我国仅在台湾有报道分布,但目前在我国黄淮海区域已经有分布,为新的入侵危害杂草,其化学防控技术未见系统报道。本研究特选择小麦田常用防除禾本科杂草的8种除草剂,于2013-2014年度在大穗看麦娘为优势杂草的冬小麦田,分别于冬前、冬季低温及春季小麦返青初期3个时期施药,以期明确各除草剂对大穗看麦娘的田间防除效果、最佳使用时间及对冬小麦的安全性。试验结果表明,啶磺草胺不同时期施药,对大穗看麦娘均有很好的防控效果,鲜重防效达到97.1%~100.0%;甲基二磺隆在不同时期施药也有很好的效果,在80.1%~98.6%之间;唑啉草酯冬前施药效果优,但冬季低温和春季返青初期施药效果较差,3次施药鲜重防效分别在99.3%~99.9%,74.1%~88.9%和46.2%~75.8%之间;炔草酯、精噁唑禾草灵于冬前施药和冬后返青初期施药效果均较好,效果在81.1%~96.8%之间,但冬季低温施药效果差,防效在41.4%~76.0%之间;其他几种药剂氟唑磺隆、肟草酮、异丙隆3次时期施药对大穗看麦娘效果均较差。     

Development of real-time onion disease monitoring system using image acquisition

In this study, real-time disease monitoring was conducted on onion which is the most representative crop in Republic of Korea, using an image acquisition system newly developed for the mobile measurement of phenotype. The purpose of this study was to improve the accuracy of prediction of disease and state variables by processing images acquired from monitoring. The image acquisition system was consisted of two parts, a motorized driving system and a PTZ (pan, tilt and zoom) camera to take images of the plants. The acquired images were processed as follows. Noise was removed through an image filter and RGB (red, green and blue) colors were converted to HSV (hue, saturation and value), which enabled thresholding of areas with different colors and properties for image binarization by comparing the color of onion leaf with ambient areas. Four objects with the most significant browning in the onion leaf to the naked eye were selected as the samples for data acquired. The thresholding method with image processing was found to be superior to the naked eye in identifying accurate disease areas. In addition, it was found that the incidence of disease was different in each disease area ratio. As a result, the use of image acquisition system in image processing analysis will enable more prompt detection of any changes in the onion and monitoring of disease outbreaks during the crop lifecycle.     

Feature extraction of hyperspectral images for detecting immature green citrus fruit

At an early immature growth stage of citrus, a hyperspectral camera of 369–1042 nm was employed to acquire 30 hyperspectral images in order to detect immature green fruit within citrus trees under natural illumination conditions. First, successive projections algorithm (SPA) were implemented to select 677, 804, 563, 962, and 405 nm wavebands and to construct multispectral images from the original hyperspectral images for further processing. Then, histogram threshold segmentation using NDVI of 804 and 677 nm was implemented to remove image backgrounds. Three slope parameters, calculated from the pairs 405 and 563 nm, 563 and 677 nm, and 804 and 962 nm were used to construct a classifier to identify the potential citrus fruit. Then, a marker-controlled watershed segmentation based on wavelet transform was applied to obtain potential fruit areas. Finally, a green fruit detection model was constructed according to Grey Level Co-occurrence Matrix (GLCM) texture features of the independent areas. Three supervised classifiers, logistic regression, random forest and support vector machine (SVM) were developed using texture features. The detection accuracies were 79%, 75%, and 86% for the logistic regression, random forest, and SVM models, respectively. The developed algorithm showed a great potential for identifying immature green citrus for an early yield estimation.     

Productivity and energy partition of late lactation dairy cows during heat exposure

Three late-lactation Holstein cows were used to determine the effects of environmental temperature on performance and energy partitioning. Each cow was housed in a respiratory chamber for 30 consecutive days and exposed to three different conditions of environmental temperature: (i) 20°C and 20°C (20°C), (ii) 25°C and 20°C (25°C), (iii) 30°C and 25°C (30°C) during the day and night, respectively. The temperature was switched in an interval of 10 days. Humidity in the chamber was maintained at 55–65% through the entire experimental period. The daily mean as well as morning and evening rectal temperatures of Holstein cows increased linearly ( P  < 0.05) as chamber temperature increased. There was a significant linear reduction in dry matter (DM) intake ( P  < 0.05) and an increase in DM digestibility ( P  < 0.05). The response in milk yield, however, was not affected by heat stress. There were no significant differences among treatments for intake energy, heat production, net energy for lactation and net energy for gain. This results of this study disagreed with the assumption that late lactation cows gave priority to increasing body tissue at the expense of milk production under thermal stress.     

内源乙烯与1-MCP互作对番茄成熟和细胞壁物质代谢的影响

【目的】探讨内源乙烯与1-MCP的相互作用对贮藏过程中番茄成熟和细胞壁代谢的影响。【方法】将破色期番茄("佛罗里达47")果实分为4组,其中2组经低压低氧(8kPa,1.7kPaO2)处理6h后,分别立即使用50μg/L液态1-MCP(HH+1-MCP)或去离子水(HH)浸泡1min;另外2组未经HH处理的番茄果实,也分别使用50μg/L1-MCP(1-MCP)或去离子水(对照)浸泡1min,测定处理后果实在贮藏(20℃)过程中成熟相关生理指标及细胞壁组分的变化。【结果】番茄果实经HH处理后,内源乙烯含量(IEC)急剧降低至对照水平的75.6%,且对1-MCP的反应敏感性有所提高。HH+1-MCP处理显著抑制了果实硬度的下降,其硬度值在贮藏第4～16天中,平均分别较对照和1-MCP处理高29.8%和15.6%;HH+1-MCP处理果实的呼吸和乙烯峰出现时间均较对照推迟4d,较1-MCP处理推迟2d,但对峰值影响未达到显著水平;与1-MCP处理相比,HH+1-MCP处理对多聚半乳糖醛酸酶(PG)、果胶甲脂酶(PME)、α-半乳糖苷酶(α-Gal)、β-半乳糖苷酶(β-Gal)等细胞壁降解酶活性的变化影响较大,对PG的影响尤为明显;HH+1-MCP处理还显著地抑制了番茄果实贮藏期水溶性和CDTA溶性糖醛酸(UA)含量的增加,其水溶性UA含量在贮藏的第6～12天平均值分别较对照和1-MCP处理低37.3%和21.9%,其CDTA溶性UA含量在贮藏的第6～12天平均值分别较1-MCP处理果实低31.4%和20.5%;凝胶渗透色谱分析结果显示,1-MCP和HH+1-MCP处理延缓了番茄果实多聚糖醛酸分子的降解过程,且后者效果更为明显。此外,本试验HH处理各项测定指标与对照无显著差异。【结论】内源乙烯含量是调节1-MCP反应能力的重要因素,解释了不同跃变型果实在成熟起始后对1-MCP反应敏感性差异的原因。     

长江下游地区部分优质粳稻品种与越光稻米支链淀粉结构特征及品质性状比较

为探讨具有优异食味品质的日本粳稻品种越光与中国长江下游地区食味品质好的水稻品种稻米的支链淀粉链长分布和主要品质特征差异,以期为中国优质水稻育种提供理论依据,选用长江下游地区公认的食味品质好的5个粳型水稻品种稻米和日本新泻地区生产的越光稻米为材料,分析支链淀粉链长分布、稻米RVA谱、直链淀粉含量、蛋白质含量、TOYO味度值等主要品质特性的差异及其相关性。越光的稻米支链淀粉链长分布和直链淀粉含量等主要品质指标与长江下游地区食味品质好的品种没有明显差异,支链淀粉长链部分(Fb3)和蛋白质含量显著低于长江下游地区食味品质好的品种,支链淀粉短/长链比(Fa/Fb3)显著高于长江下游地区食味品质好的品种。越光稻米中Mg、K含量以及淀粉谱特性中最高黏度、崩解值均显著高于长江下游地区食味品质好的品种。支链淀粉的短链部分(5≤DP≤12)所占比率与最高黏度值和崩解值呈显著正相关,Fa/Fb3与最高黏度和崩解值均呈显著正相关。由此认为,通过育种手段改善稻米的支链淀粉理化特性,并在栽培措施上通过降低氮肥施用量来降低稻米中蛋白质含量,是提高长江下游地区水稻品种食味品质的有效途径。     

碱胁迫下粳稻幼苗前期耐碱性的数量性状基因座检测

以粳粳交“高产106/长白9号”F_2:3代200个家系为作图群体, 在0.15% Na₂CO₃溶液的碱性胁迫下, 进行了水稻耐碱性鉴定, 并以SSR标记构建的分子连锁图谱为基础, 对水稻幼苗前期的根数、根长和苗高及其相对碱害率进行了数量性状基因座(QTLs)的检测。结果表明, 上述性状在F₃家系群中均表现为具有1~2个峰的连续分布, 认为由主效基因和微效基因共同控制的数量性状。共检测到与碱胁迫下幼苗前期根数、根长和苗高及其相对碱害率相关的QTL 26个, 分布于第1、5、6、7、8、9和11染色体上。其中, 碱胁迫下与根数相关的QTL 4个, qRN6-1和qRN11对表型变异的解释率较大, 分别为29.91%和13.42%;与根数相对碱害率相关的QTL 5个, qRRN11-2对表型变异的解释率较大, 为23.86%;与根长相关的QTL 6个, qRRL11-2对表型变异的解释率较大, 为21.06%;与根长相对碱害率相关的QTL 2个, 但对表型变异的解释率均较低;与苗高相关的QTL 5个, qSH1和qSH11-2对表型变异的解释率较大, 分别为15.81%和16.53%;与苗高相对碱害率相关的QTL 4个, qRSH5和qRSH6-2对表型变异的解释率分别为29.89%和34.63%。而这些解释率较大的QTL所处的标记区间距离, 除qRN6-1相对较小(19.0 cM)外, 其余QTL的标记区间距离均大于26.3 cM, 需作进一步的精细定位。在所检测到的QTL中, 13个QTL的增效等位基因均来自耐碱亲本长白9号, 而其余QTL的增效等位基因来自敏碱亲本高产106;基因的主要作用方式为超显性或部分显性。     

中国2 种螟蛾科幼虫的形态记述(鳞翅目)

详细记述了中国螟蛾科二化螟Chilo suppressalis (Walker)和三化螟Tryporyza incertulas (Walker)幼虫的形态特征, 并提供了形态特征图。所有标本均保存在中国计量学院生命科学学院标本室。图2参7