太空诱变哈密瓜花性变异初报

利用太空诱变技术对哈密瓜杂种一代种子进行诱变,经田间植物学和生物学观察,发现出现变异,得到了主蔓连续着生完全花、没有雄花的哈密瓜新型资源。     

Nitrogen effects on cantaloupes

Abstract

The NO₃ levels in cantaloupe (Cucumis melo L.) petioles relate closely to N treatment and reflect the N status of the cantaloupe plant. Suggested levels of petiole NO₃ in cantaloupes grown in Arizona are presented. Nitrogen treatment had little effect on melon size, earliness, or most storage quality factors that were evaluated except that deficiencies resulted in lower netting, poor general appearance and an increase in cull melons.     

甜瓜嫁接技术研究初探

为了增强甜瓜对高温、干旱和病害的抗逆能力,减少水、肥、药的用量,保证甜瓜品质和经济效益,同时有效防治甜瓜枯萎病、蔓枯病等病害,以甜瓜嫁接专用品种白籽南瓜为砧木,以西州密25号为接穗进行嫁接试验,对比分析了甜瓜长势、产量、品质和节水节肥情况。结果表明:甜瓜嫁接后植株生长势强,抗逆性能力提高,667 m~2增产6.4%,口感脆甜、汁多,货架期长,值得在吐鲁番市示范推广。     

The influence of calcium on growth of selected vegetable species in the presence of ammonium nitrogen

Growth of cabbage (Brasslca oleracea L.), cantaloupe (Cucumis melo L.), squash (Cucurbita pepo L.), chile pepper (Capsicum annuum L.), tomato (Lycopersicon esculentum Mill)., radish (Raphanus sativus L.), and Swiss chard (Beta vulgaris L.) was enhanced when supplied with additional Ca in the presence of NH₄‐N over those with normal Ca. Ammonium uptake as measured by residual NH₄ in soil leachate was lowered indicating possible increased uptake in the presence of additional Ca.     

Polygalacturonase-inhibiting protein activity in cantaloupe fruit as a function of fruit maturation and tissue origin

Netted cantaloupe (Cucumis melo var. cantalupensis cv. Magnum 45) were harvested from 5 to 35 days postanthesis. The fruit of each age group were divided into exocarp, outer mesocarp, mid mesocarp, inner mesocarp, placenta, and seed. Each tissue was extracted and assayed for polygalacturonase-inhibiting protein (PGIP) activity against polygalacturonases (PGs) from three fungal pathogens of cantaloupe fruit. The PGIP activity of all tissues except placenta was high from the flower stage through the first week of fruit development but decreased markedly between 5 and 10 days postanthesis. PGIP activity against Phomopsis cucurbitae PG remained high and nearly constant in placental tissue throughout fruit development. However in this same tissue, PGIP activity against Fusarium solani PG decreased during fruit development to about 25% of its level in the 5-day-old fruit. This differential change in PGIP activity toward the two PGs suggests that different forms of the inhibitor are expressed between early and late stages of cantaloupe fruit development. The results also illustrate the importance of using multiple pathogen enzyme systems that can provide an opportunity for more accurate elucidation of mechanisms involved in the host–pathogen interaction. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. All programs and services of the US Department of Agriculture are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, age, marital status, or handicap. The article cited was prepared by a USDA employee as part of his/her official duties. Copyright protection under US copyright law is not available for such works. Accordingly, there is no copyright to transfer. The fact that the private publication in which the article appears is itself copyrighted does not affect the material of the US Government, which can be freely reproduced by the public.     

基于LF-NMR及不同干燥方法的哈密瓜片含水率预测模型

为建立稳健、适用范围更广的哈密瓜片含水率预测模型,采用不同干燥方法(热风干燥(Hot Air drying,HA)和红外辐射干燥(Infrared drying,IR)),在相同温度水平下(50、60、70℃)对哈密瓜片进行干燥,采用低场核磁共振技术(Low-Field Nuclear Magnetic Resonance,LF-NMR)对比分析干燥过程的水分迁移规律及2种干燥方法间的差异,并结合化学计量学方法建立含水率预测模型。结果表明:无论HA还是IR,一定温度范围内高温有利于提高干燥速率,缩短干燥时间;且IR与HA相比干燥时间缩短20.0%~37.5%。经LF-NMR分析,在HA和IR过程中,自由水峰面积逐渐降低,不易流动水峰面积及结合水峰面积呈波动变化;自由水峰顶横向弛豫时间不断降低,不易流动水峰顶横向弛豫时间因干燥方式和干燥温度的差异呈不同的变化趋势;与HA过程中结合水峰顶横向弛豫时间逐渐降低不同,其在IR干燥初期短暂上升,后呈下降趋势。基于HA、IR数据集结合化学计量学方法建立的哈密瓜片含水率预测模型中,偏最小二乘回归(Partial Least Squares Regression,PLSR)模型具有更好的性能,模型预测决定系数R_P² 大于0.99,表明PLSR结合LF-NMR可实现哈密瓜片含水率的快速检测,且不受干燥方法不同引起水分状态差异的影响。研究结果为基于LF-NMR和多加工手段的果蔬含水率预测模型的建立提供参考。     

南瓜蚜传黄化病毒遗传多样性分析

 哈密瓜是新疆重要的经济作物之一。南瓜蚜传黄化病毒(cucurbit aphid-borne yellows virus, CABYV)是世界重要的瓜类黄化病毒,在新疆哈密瓜植株上普遍发生,严重威胁新疆哈密瓜的品质与产量。本研究从新疆阿克苏市随机采集120份哈密瓜叶片样品,经过RT-PCR检测证实38个样品为CABYV阳性,从阳性样品中分离、测序、克隆得到一个新的CABYV分离物。将该分离物与22个来自不同国家的分离物(NCBI)进行核酸和氨基酸序列一致性和系统发育分析,结果显示23个CABYV分离物根据地域差异被划分为2个不同进化群体。进一步对不同CABYV群体进行遗传多样性分析,结果表明CABYV在寄主和地理种群之间存在明显的遗传差异。选择压分析和偏离中立性检验显示CABYV种群近期可能发生了种群扩张或背景选择,并且负向选择可能是CABYV遗传变异的原因之一。本文较全面研究了CABYV的发生、危害与遗传结构及进化机制,可为新疆病毒病防治提供理论指导。     

吐鲁番大田哈密瓜新品种引进初探

通过对引进的2 个哈密瓜品种青花蜜、酥香七号与本地常规种植的2 个主打品种西州蜜25 号、西州蜜17 号在生物学性状、抗病性、商品性状、口感、产量等方面进行了观测、比较，得出初步结 论，根据不同消费者的喜好和市场需求，可以选择引进的青花蜜、酥香七号在本地推广种植和销售。     

鲜切甜瓜主要致腐真菌的分离鉴定

鲜切甜瓜由于受到机械损伤，易被真菌污染。本研究以西州蜜25号鲜切甜瓜为试材，使用稀释涂布平板法、三点法对其腐败真菌进行分离纯化并测定其致腐能力，使用形态学及rDNA-ITS序列分析相结合的方法进行鉴定。结果表明：鲜切甜瓜主要腐败真菌共有8种，其中腐败霉菌有6种，按其致腐能力由大到小排列，分别为赭曲霉（Aspergillus ochraceus）、球状枝孢霉（Cladosporium sphaerospermum）、葡萄茎枯病霉（Didymella glomerata）、萨氏曲霉（Aspergillus sydowii）、核生枝顶孢霉（Acremonium sclerotigenum）、褶皱曲霉（Aspergillus rugulosus），腐败酵母有2种，分别为大隐球酵母（Cryptococcus magnus）和粘质红酵母（Rhodotorula mucilaginosa）。     

Detection of Pseudomonas syringae pv. aptata in Irrigation Water Retention Basins by Immunofluorescence Colony-staining

Bacterial blight of cantaloupe (Cucumis melo) caused by Pseudomonas syringae pv. aptata was first observed in south-western France and has since spread to all cantaloupe-growing areas of this country. Use of pesticides registered for this disease has proved ineffective and no commercial cultivars of cantaloupe are resistant to this blight. To develop control strategies for this disease, the principal sources of inoculum were investigated. Among the different sources of inoculum studied, we report the isolation of P. syringae pv. aptata from irrigation water retention basins in south-western France using the immunofluorescence colony-staining (IFC) method. In this study, the pathogen was detected at a low concentration (12 and 70cful^–1) in two different retention basins. These results suggest that P. syringae pv. aptata can survive in water used to irrigate cantaloupe crops and could be a source of inoculum for epidemics of bacterial blight. To develop control strategies for this bacterial disease, the importance of water retention basins as sources of inoculum for bacterial blight of cantaloupe needs to be evaluated relative to other potential sources such as seeds, plants from nurseries and plant debris in the soil.