不同材质果袋对哈密瓜果实微域环境及品质的影响

【目的】研究不同材质果袋对哈密瓜果实微域环境及品质的影响,为哈密瓜田间生产提供指导。【方法】以“黄皮9818”甜瓜品种为材料,采用白纸袋、硫酸纸袋、塑料膜袋、淋膜纸袋4种不同材质的果袋,不套袋(CK)为对照,进行哈密瓜果实套袋试验,并测定不同材质果袋中微域环境,及对哈密瓜外观和营养品质的影响。【结果】哈密瓜套袋后,微域环境的温度、光照均低于对照(CK),除塑料膜袋外,其它材质果袋均能有效防止果面灼伤;而各套袋处理哈密瓜营养品质中总酸、蛋白、水解还原糖、VC含量无明显差异。【结论】在哈密瓜露地栽培条件下,淋膜纸袋为较理想果袋,果实平均单果重(1.52kg)、商品率(82.80%)最高,且果面鲜亮干净,网纹细密,水浸斑较少。     

Weed competition in muskmelon and its effects on yield and fruit quality

Field studies were conducted at Newe Ya'ar (northern Israel) during 1986 and 1988 to examine the critical period of weed competition in muskmelon (Cucumis melo L. cv. Galia). The yield of the control (weed free throughout the season) in 1988 was 45% higher than in 1986. In 1988, weed control was required within 6 weeks after seedling emergence in order to maintain fruit quality. Total yield was reduced significantly only if weeding started 7 weeks after emergence or later. Muskmelon remained competitive and maintained optimal yield potential if kept weed free during the first month of crop growth. The critical period for weed control in muskmelon was at the initiation of the rapid fresh-weight accumulation of the weeds and the pistillate flowering peak of the crop. Under Newe Ya'ar conditions this occurred 4–6 weeks after emergence of the crop.     

甜瓜属野生种铝胁迫诱导基因ChAI的克隆及序列分析

应用同源序列克隆策略从铝盐胁迫处理的甜瓜属野生种(Cucumis hystrix Chakr.) 叶片中获得了612bp的片段,通过在EST数据库进行同源检索,发现一条甜瓜EST序列（GenBank登录号：AM724963.2）与之高度同源,据此设计引物并经RT-PCR扩增和序列拼接,最后获得了铝诱导基因cDNA序列全长,命名为ChAI (GenBank登录号：FJ968438 )。序列分析表明该基因全长967bp,其中开放读码框(ORF)长711bp编码236个氨基酸组成的多肽,5′ 和3′ 端非编码区长度各为15bp和241bp。DNAMAN同源性分析表明该基因与葡萄、棉花、羊乳（轮叶党参）、白骨壤（真红树植物）、拟南芥等植物的铝诱导蛋白的氨基酸序列具有78.6%以上的同源性。运用半定量RT-PCR技术对ChAI 基因的转录水平进行分析,根据该基因在铝胁迫下大量表达推测ChAI 与耐铝盐胁迫响应相关,但具体耐铝胁迫机制还有待深入研究。     

华莱士瓜果实采后芳香物质成份的GC/MS分析

通过GC-MS分析,从华莱士瓜果实中检出45种不同成分的芳香物质。主要的物质为软脂酸、亚麻酸、亚油酸、油酸、顺-十六碳烯酸、二十八烷、二十三烷、乙酸-3-甲基丁酯、乙酸苯甲酯、3-羟基-2-丁酮、二十七烷、硬脂酸、乙酸乙酯、乙酸丙酯、乙酸-2-甲基丙酯、丁酸乙酯、乙酸丁酯、乙酸-2-甲基丁酯、2,2'-甲二氧基丙烷、2-甲基丙基肼、苯甲醇21种物质,占芳香物质总含量的71%。     

沈阳地区黄瓜根寄生线虫的种类鉴定

１９９０～１９９１年对采自沈阳地区的黄瓜根寄生线虫种类进行分类鉴定研究。本文共鉴定出５个属１１种线虫，即：垫刃线虫属Ｔｙｌｅｎｃｈｕｓ１个种，Ｔｙｌｅｎｃｈｕｓｍａｉｕａ；丝尾垫刃线虫属Ｆｉｌｅｎｃｈｕｓ３个种，Ｆｉｌｅｎｃｈｕｓｂｕｔｔｅｕｓ，Ｆ．ｃｒｉｎｉｆｏｒｍｉｃａｕｄａｔｕｓ，Ｆ．ｈａｍａｔｕｓ；针线虫属Ｐａｒａｔｙｌｅｎｃｈｕｓ１个种，Ｐａｒａｔｙｌｅｎｃｈｕｓｄｉａｎｔｈｕｓ；滑刃线虫属Ａｐｈｅｌｅｎｃｈｏｉｄｅｓ５个种，Ａｐｈｅｌｅｎｃｈｏｉｄｅｓｃｏｍｐｏｓｔｉｃｏｌａ，Ａ．ｄｕｂｉｕｓ，Ａ．ｐａｒａｂｉｃａｕｄａｔｕｓ，Ａ．ｐａｒａｓｃａｌａｃａｕｄａｔｕｓ，Ａ．ｓｕｂｔｅｎｕｉｓ；真滑刃线虫属Ａｐｈｅｌｅｎｃｕｓ１个种，Ａｐｈｅｌｅｎｃｈｕｓａｖｅｎａｅ．其中，国内新记录种７个．     

烟粉虱卵在黄瓜上的空间分布及抽样技术

对烟粉虱卵在黄瓜上的空间分布型进行了研究.结果为:Iwao回归模型α=1.148 2＞0,β=1.423 1＞1;Talor幂法则loga=0.398 4＞0,b=1.517 4＞1.表明烟粉虱卵呈聚集分布, 其聚集度随种群密度的升高而下降, 分布的基本成分是个体群, 个体间相互吸引.采用Iwao方法求出不同卵密度下的最适抽样数.     

Effects of Different Irrigation Regimes and Mulches on Yield and Macronutrition Levels of Drip-Irrigated Cucumber Under Open Field Conditions

ABSTRACT

The effectiveness of different mulch types on fruit yield, leaf-nutrient composition, and normal plant growth parameters was investigated in order to maximize water use efficiency (WUE) in cucumber grown under water stress. Treatments were (1) bare soil + water stress (WS), (2) bare soil + unstressed (control, C), (3) black polyethylene mulch + water stress (BPM + WS), (4) wheat straw mulch + water stress (WSM + WS), and (5) wheat straw mulch plus black polyethylene mulch + water stress (WSM + BPM + WS). Seasonal crop evapotranspiration was between 492 and 960 mm. Seasonal irrigation water amounts were 965 and 485 mm for the C and WS treatments, respectively. The WUE ranged from 3.40 to 5.78 kg m^?3, while irrigation water-use efficiency (IWUE) was between 3.39 and 6.08 kg m^?3. IWUE and WUE were increased under WS treatments with mulching compared with the control treatment, as mulching significantly reduced the amount of irrigation water required. Both BPM and WSM improved the fruit yield, fruit size, plant dry matter, total leaf area, and chlorophyll and nutrient concentrations in leaves under the stressed treatments, while these two mulches in combination (BPM + WSM) caused further increases in these parameters. This study confirms that limiting soil evaporation with mulches is a key action to take to save irrigation water and to improve WUE and IWUE. Because use of drip irrigation with mulching can increase WUE, this strategy might be used for vegetable production in semi-arid regions where irrigation water is limited.     

Effects of exogenous spermidine on the photosynthesis of Cucumis sativus L. seedlings under rhizosphere hypoxia stress

With water culture, this paper studied the effects of exogenous spermidine (Spd) on the net photosynthetic rate (P _n), intercellular CO₂ concentrations (C _i), stomatal conductance (G _s), transpiration rate (T _r), apparent quantum yield (Φ _c), and carboxylation efficiency (CE) of cucumber seedlings under hypoxia stress. The results showed that P _n decreased gradually under the hypoxia stress, and reached the minimum 10 days later, which was 63.33% of the control. Compared with that of the hypoxia-stressed plants, the P _n 10 days after the application of exogenous Spd increased by 1.25 times. A negative correlation (R ²=0.473−0.7118) was found between _{P n} and C _i, and G _s and T _r changed in wider ranges, which decreased under the hypoxia-stress, but increased under the hypoxia-stress plus exogenous Spd application. There was a significant positive correlation between G _s and T _r (R ²=0.7821−0.9458), but these two parameters had no significant correlation with P _n. The hypoxia stress induced a decrease of Φ _c and CE by 63.01% and 72.33%, respectively, while the hypoxia stress plus exogenous Spd application made Φ _c and CE increase by 23% and 14%, respectively. The photo-inhibition of cucumber seedlings under hypoxia stress was mainly caused by non-stomatal inhibition, while the exogenous Spd alleviating the hypoxia stress by repairing photosynthesis systems. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(9): 1609–1612 [译自: 应用生态学报]     

Current status of genetic transformation technology developed in cucumber (Cucumis sativus L.)

Genetic transformation is an important technique for functional genomics study and genetic improvement of plants. Until now, Agrobacterium-mediated transformation methods using cotyledon as explants has been the major approach for cucumber, and its frequency has been up to 23%. For example, significantly enhancement of the transformation efficiency of this plant species was achieved from the cotyledon explants of the cultivar Poinsett 76 infected by Agrobacterium strains EHA105 with efficient positive selection system in lots of experiments. This review is to summarize some key factors influencing cucumber regeneration and genetic transformation, including target genes, selection systems and the ways of transgene introduction, and then to put forward some strategies for the increasing of cucumber transformation efficiency. In the future, it is high possible for cucumber to be potential bioreactor to produce vaccine and biomaterials for human beings.     

低温弱光对黄瓜幼苗地上部和根系生长与呼吸作用的影响

以冷敏感作物黄瓜(Cucumis sativus)为材料,研究低温弱光(100μmol/m2.s-1、8℃)对黄瓜幼苗地上部及根系生长与呼吸作用的影响。结果表明:低温弱光抑制了黄瓜幼苗地上部与根系的生长,并导致根冠比由0.17增加为0.26。叶片总呼吸(Vt)、细胞色素呼吸(ρ’Vcyt)和抗氰呼吸(ρValt)在胁迫初期瞬间急剧增强,后随处理时间延长又迅速下降,其中Vt和ρ’Vcyt低于对照水平,但ρValt仍与对照水平相当;低温弱光虽然降低了根系ρ’Vcyt,但诱导ρValt显著增强,最终导致Vt增加;低温弱光下根系ρValt/Vt的增加程度明显高于叶片。低温弱光下叶片线粒体呼吸控制率下降程度大于根系,说明低温弱光对叶片线粒体的伤害大于根系。