1-MCP处理对“丽格”海棠果实采后生理及品质的影响

以"丽格"海棠果实为试材,研究经1.0μL/L的1-MCP处理后,室温(20±1)℃条件下贮藏的海棠果实品质和生理变化,并利用主成分对采后测定的各项生理指标进行分析。结果表明,与不加1-MCP的对照组相比,1-MCP处理可保持海棠果实硬度,抑制可溶性固形物(TSS)含量的升高,减缓VC含量的降低、果皮叶绿素的分解和过氧化物酶(POD)活性的下降,降低呼吸强度和乙烯生成速率,有效地延缓果实衰老,使海棠果更耐贮藏。主成分分析在特征值大于1时将经1-MCP处理后的海棠果实8个生理指标综合为2个因子,累积方差贡献率达到84.44%,其中第1主成分主要代表果肉硬度和叶绿素信息,第2主成分主要代表乙烯释放量信息。     

异硫氰酸丙烯酯毒杀松材线虫作用机制初步研究

对异硫氰酸丙烯酯毒杀松材线虫作用机制进行了初步研究。测定了其对线虫虫体形态、运动行为、体内总糖和蛋白质含量的影响,以及处理前后线虫体内过氧化氢酶(CAT)、乙酰胆碱酯酶(AChE)和谷胱甘肽-S-转移酶(GST)活性变化。结果表明:经异硫氰酸丙烯酯处理后的松材线虫虫体形态严重扭曲,运动形态出现由正常的S形变化为多节弯曲和螺旋状卷曲等异常状况,线虫行动随时间的推移变得迟缓,最终呈C形、新月形或直接死亡。随着异硫氰酸丙烯酯处理质量浓度的增大,线虫体内总糖和蛋白质含量显著上升,糖和蛋白质的代谢发生紊乱;线虫体内CAT、AChE和GST活性显著降低,且均低于对照组,表明线虫体内氧化和抗氧化作用失衡;细胞受到极大的影响,神经系统遭到破坏,解毒能力明显降低。研究结果可为研究利用异硫氰酸丙烯酯作为植物源杀线虫剂提供依据。     

Studies on mutlispecific resistance of gastrointestinal nematodes to benzimidazoles on dairy-goat farms

Multispecific resistance to benzimidazoles was studied in three selected farms. These farms had bred dairy goats for more than 15 years. The helminths were introduced with the goats at the establishment of the farms which afterwards remained isolated. Nematode resistance could then be related to their own management practices. Faecal egg count tests and egg hatch assays were performed to assess intensity of resistance. The generic (infective larvae in faecal cultures) and specific richness (adult worms) were assessed. The resistant species were Trichostrongylus colubriformis, Teladorsagia circumcincta, Haemonchus contortus and Oesophagostomum venulosum. Faecal egg count reduction tests and egg-hatch assays did not match exactly. Faecal larval counts after treatments gave a distorted picture of multispecific resistance: Haemonchus and Oesophagostomum were very largely over represented. The number of species found in the three farms was relatively low compared with other reports in goat farms of the area. This reduction of diversity might also be due in part to characteristics of breeding management and history (use of permanent pasture and introduction of goats at the establishment of farm).     

中国结缕草属(Zoysia spp.)植物抗寒性评价

在广泛收集结缕草属(ZoysiaWild.)种质资源基础上,按照形态类型和地理分布,选取40份种质,采用电导法(EL)对其抗寒性进行初步评价。以半致死温度(LT50)为评价指标,在参试材料中除大穗结缕草和来自台湾岛海边沙地的沟叶结缕草外,其它种质都较天堂-419(对照)抗寒;在结缕草属内,抗寒性具有明显的种间差异,耐寒性依次为日本结缕草>中华结缕草>沟叶结缕草>细叶结缕草>长花中华结缕草>大穗结缕草,其中细叶类型的沟叶结缕草和细叶结缕草抗寒性变异较大;日本结缕草和中华结缕草抗寒性变异与地理分布之间没有显著关系,但分布在海边的种类和种质抗寒性明显较低;结缕草属及其中华结缕草的抗寒性与叶长、叶宽以及叶背面被毛之间均存在显著的负相关关系,但这种关系不体现在日本结缕草上。实验结果还表明,EL方法是评价结缕草属抗寒性较为可靠的方法之一。     

海南半干旱地区芒果间作柱花草及作物效益初探

1998～2001年在海南东方干旱半干旱燥红土芒果与柱花草及作物间作示范区的实践表明，在芒果园间作扁豆、柱花草、番薯和花生可显著提高芒果挂果率，芒果收入比芒果单种分别增加97．79％、98．53％、54．41％和48．28％，果园综合收入比芒果单种分别增加108．55％、98．53％、97．98％和91．58％，同时，果园间作可显著提高果园土壤有机质、全氮、速效磷的含量和土壤pH值，间作扁豆使土壤有机质含量增加53．3％，间作柱花草使土壤全氮增加43．92％，速效磷增加78．16％，从而达到了以短养长、增加农民收入、提高土壤肥力和持续管理利用的目的。     

汕头市松材线虫病的防治

基于汕头市濠江区已发现松材线虫病疫情的实际情况,针对该病的防治特点,结合汕头市各辖区山林的实际情况,从判断、预防、治理三个方面提出相应的防治对策,为科学防控该病在我市的扩散危害提供参考。     

陕西省木本植物炭疽菌分类研究

报导了发生在陕西省木本植物上的炭疽菌属ＣｏｌｌｅｔｏｔｒｉｃｈｕｍＣｏｒｄａ３个种，其中包括１个中国新纪录种，即：胶孢炭疽菌Ｃｏｌｌｅｔｏｔｒｉｃｈｕｍｇｌｏｅｏｐｏｒｉｏｉｄｅｓ（Ｐｅｎｚ）。Ｓａｃｃ，壳皮炭疽菌Ｃｏｌｌｅｔｏｔｒｉｃｈｕｍｃｒａｓｓｉｐｅｓ（Ｓｐｅｇ．）Ａｒｘ和梭孢炭疽菌ＣｏｌｌｅｔｏｔｒｉｃｈｕｍａｃｕｔａｔｕｍＳｉｍｍｏｎｄｓ（中国新纪录种）。     

Acquired resistance triggered by elicitins in tobacco and other plants

Elicitins are a family of proteins excreted byPhytophthora spp. They exhibit high sequence homology but large net charge differences. They induce necrosis in tobacco plants which then become resistant to the tobacco pathogenPhytophthora parasitica var.nicotianae. In stem-treated plants, resistance was not restricted to the site of elicitin application, but could be demonstrated by petiole inoculation at all levels on the stem. Resistance was already maximum after two days and lasted for at least two weeks. It was effective not only towardsP. p. var.nicotianae infection, but also against the unrelated pathogenSclerotinia sclerotiorum. In contrast to dichloroisonicotinic acid, an artificial inducer of systemic acquired resistance, which was increasingly effective with doses ranging from 0.25 to 5mole per plant, the basic elicitin cryptogein exhibited a threshold effect, inducing near total resistance and extensive leaf necrosis above 0.1 nmole per plant. Between 1 and 5 nmole, acidic elicitins (capsicein and parasiticein) protected tobacco plants with hardly any necrotic symptom. Elicitins exhibited similar effects in various tobacco cultivars andNicotiana species, although with quantitative differences, but induced neither necrosis nor protection in other SolanaceÆ (tomato, petunia and pepper). Among 24 additional species tested belonging to 18 botanical families, only some BrassicaceÆ, noticeably rape, exhibited symptoms in response to elicitins, in a cultivar-specific manner. Elicitins appear to be natural specific triggers for systemic acquired resistance and provide a tool for unraveling the mechanisms leading to its establishment.Abbreviations AR acquired resistance - HR hypersensitive response - INA 2,6-dichloroisonicotinic acid - Ppn Phytophthora parasitica var.nicotianae - SAR systemic acquired resistance