环境友好型保水剂的合成、性能及应用

[目的]以过硫酸铵(APS)为引发剂,N,N'-亚甲基双丙烯酰胺(NMBA)为交联剂,通过壳聚糖(CTS)和瓜尔胶(GG)接枝丙烯酸(AA)制备新型高耐盐保水剂,探究其合成过程最佳反应条件,研究其对盐碱地土壤保水保肥的效果。[方法]利用水溶液聚合法制备保水剂,通过单因素试验(AA中和度、GG投加量、APS用量、NMBA用量)研究保水剂的最佳合成条件,用FTIR和SEM对产物进行表征,并对产物的环境适应性(盐溶液类型及浓度、溶液pH值)及其加入盐碱土后对于土壤水肥保持的效果进行研究。[结果]当AA中和度为85%,GG投加量为0.2g,APS与NMBA用量分别为单体总量的0.3%和0.02%时,该保水剂在去离子水和0.9%NaCl溶液中的吸收效率分别为1 128g/g和185g/g,此时产物的吸收效果达到最佳。红外光谱与电镜扫描分析结果表明CTS,GG和AA都参与了聚合反应,产物具有较好的空间网络结构与表面形态。该保水剂在溶液pH值为4~10的范围内吸收效率较稳定,但是当溶液中存在阳离子时其吸收效率明显降低,阳离子类型对其吸收效率的抑制作用从大到小依次为:Mg2+Ca2+Na+K+。当保水剂加入到盐碱土时,既能提高土壤持水能力又能抑制土壤氮肥和钾肥的淋溶损失。[结论]本研究自制保水剂具有较好的耐盐效果,环境适应性强,单体环境友好,将其加入盐碱土壤时能够有效降低土壤水肥的淋溶损失。     

硅酸镁铝及其与黄原胶协同使用对30%辛硫磷微囊悬浮剂贮存物理稳定性的影响

以流变学方法探讨了在30%辛硫磷微囊悬浮剂中添加硅酸镁铝及协同使用硅酸镁铝与黄原胶对改善微囊悬浮剂贮存物理稳定性的影响。结果表明,单独使用硅酸镁铝即可明显改善微囊悬浮剂的贮存物理稳定性,当其质量分数为2%时,体系即产生明显的触变性,常温贮存(室温,60 d)和热贮(54 ℃±2 ℃,14 d)的析水率分别由68.13%和70.68%减小到3.75%和5.31%;当硅酸镁铝和黄原胶协同使用时,加入质量分数为0.5%的硅酸镁铝和0.3%的黄原胶即可明显改善微囊悬浮剂的贮存物理稳定性,且随着硅酸镁铝用量的增加,体系的触变性也逐渐增强,更有利于改善体系的物理稳定性。表明硅酸镁铝单独使用或与黄原胶协同使用均可明显改善微囊悬浮剂的贮存物理稳定性。     

Multi-scale site and landscape effects on the vulnerable superb parrot of south-eastern Australia during the breeding season

The threatened superb parrot of south-eastern Australia exemplifies many of the challenges associated with research on wide-raging organisms which live ‘off-reserve’. Challenges include that most land is privately owned and that landscape use by such organisms does not always conform to traditional schematic and categorical landscape/fragmentation models. A multi-scale approach for embedding the detection of site-level and landscape context effects into landscape sampling design and subsequent statistical analysis is presented. The superb parrot was found scattered at varying densities throughout the agricultural landscapes of the South-West Slopes, much of which was privately owned. It responded to site-level variables and the surrounding landscape context. Overall, the superb parrot favoured lower elevation sites which were dominated by scattered, open woodlands, where Blakely’s red gum was a significant component. Mean plant productivity within 2 km, levels of woody tree cover within 3 km and (with caveats) length of roads within 3 km had a major effect on site-level response, indicating conditions in the surrounding local landscape are important to the superb parrot. This multi-scale response requires a multi-scale conservation and restoration strategy. The importance of open tree cover and amounts of Blakely’s red gum are a matter for concern, due to a general lack of tree regeneration and the particular susceptibility of Blakely’s red gum to dieback. The scattered trees in the agricultural matrix were important to the superb parrot, suggesting that it views these landscapes as a continuum of usable habitat. Strategies for restoration of larger habitat remnants should also include regeneration of trees in scattered pattern in the wider landscape, and Blakely’s red gum should be part of any strategy along with other key species such as yellow and white box. The landscape sampling approach successfully addressed the challenges of whole-landscape research. This highlights the value of ‘off-reserve’ studies across whole landscapes.     

Ultrastructural Changes and Production of a Xanthan-Like Polysaccharide Associated with Scald of Sugarcane Leaves Caused by Xanthomonas albilineans

Leaf scald is a vascular disease of sugarcane caused by Xanthomonas albilineans. Scalded leaves show white-yellowish streaks alternating with green zones in parallel to the main veins. These zones develop large bulliform cells, probably as a consequence of the wilting process. Moreover, a gum exudate occludes phloem and bundle vessels, and partially enters mesophyll cells. Some lysigenic cavities appear near the xylem. However, the white-yellowish streaks show both phloem and xylem completely occluded by the gum and the overall mesophyll appears to be full of this bacterial secretion, as revealed by scanning electron microscopy. The gum in conducting tissues has been purified from juice obtained from scalded stalks by precipitation with isopropyl alcohol and size-exclusion chromatography. It was identified as a xanthan-like polysaccharide and found to be composed of glucose, mannose and glucuronic acid by acidic hydrolysis and capillary electrophoresis.     

白及胶复合保鲜液对芒果的保鲜作用研究

[目的]自制白及胶复合保鲜液用于芒果的保鲜,以解决新鲜芒果贮藏和运输难的问题。[方法]以白及胶、金银花-槐米-广藿香制得的天然抑菌剂、纳米二氧化钛为原料制得白及胶复合保鲜液,并研究其对芒果的保鲜作用。[结果]白及胶复合保鲜液处理的芒果各项测定指标均优于国内同类产品鲜立克保鲜液,其能有效延缓芒果的失重、转黄、腐烂,降低芒果呼吸强度,抑制可滴定酸、Vc、可溶性总固形物含量的下降,明显抑制病害,降低腐烂指数,保持果实的良好品质,延长果实的贮藏寿命。[结论]白及胶复合保鲜液的原辅料均来源于天然生物,无毒、无害、可食用、安全可靠、易于生物降解、不污染环境,具有广阔的应用前景。     

苦豆子胶热水提取工艺研究

以苦豆子种子为原料,采用沸水浸提法提取苦豆子胶,通过单因素及正交试验研究浸提时间、浸提次数、浸提温度及液料比对提取率的影响。结果表明,苦豆子胶的最佳提取工艺为：浸提次数3次,浸提温度90℃,浸提时间6 h,液料比22.5,该条件下苦豆子胶提取率为94.50±0.46%。     

桃树流胶病的发生与防治

桃树流胶病是危害桃树的一种常见的果树疾病。阐述河南省平顶山市舞钢地区桃树流胶病的发生症状以及发病原因与环境因素、立地条件以及栽培管理、树龄树势的关系。提出了改善果园通风透光条件加强果园管理等可有效减轻桃树流胶病发生的技术措施。     

硅窗气调包装与普通气调包装对茶树菇贮藏品质的影响

为了提高茶树菇的贮藏品质,通过采用硅窗气调包装与普通气调包装对茶树菇进行贮藏,研究硅窗气调包装与普通气调包装的茶树菇总糖含量、原果胶含量、可溶性果胶含量、蛋白质含量及总氨基酸含量、游离氨基酸含量和粗纤维含量的变化情况。结果表明：与普通气调包装相比,硅窗气调包装贮藏的茶树菇总糖含量、原果胶含量、蛋白质含量及总氨基酸含量下降较慢,而粗纤维含量、可溶性果胶含量及游离氨基酸含量增加较少。由此得出,硅窗气调包装是一种贮藏茶树菇比较好的方法,用这一方法贮藏的茶树菇保持了较多的糖类和蛋白质,保持了较好的口感和相应的脆度,具有更好的贮藏品质。     

蜂胶加工制品 亟待深入研究

蜂胶制品因保健效果好而热销的同时,市场上暴露出了许多问题,然而依靠现有的研究成果,这些问题还不能得到有效解决,需要进行更深入的研究,还市场一个公平竞争的环境,还消费者一个明白的消费。     

Screening Corymbia populations for resistance to Puccinia psidii

The exotic rust pathogen Puccinia psidii is now widespread along the east coast of Australia from temperate Victoria to tropical far north Queensland, with a current host range exceeding 200 species from 37 myrtaceous genera. To determine the threat P. psidii poses to plantation and native eucalypts, artificial inoculation was used to screen germplasm of spotted gum (Corymbia spp.) for resistance to the biotype of P. psidii that has become established in Australia. The objective was to characterize resistance to P. psidii within the Corymbia species complex so that management strategies for the deployment of germplasm from existing breeding programmes of these spotted gum species could be developed. Symptom development initiated 7 days after inoculation, with resistant and susceptible seedlings identified within all species, provenances and families. Inter‐ and intraspecific variability in rust resistance was observed among spotted gum species. There was no apparent relationship between climatic conditions at the provenance origin and disease resistance. The heritability estimates for all assessments are moderate to high and indicate a significant level of additive genetic variance for rust resistance within the populations. The results of this study clearly identify potential to select for resistance at the family level within the tested populations. While the potential for P. psidii to detrimentally impact upon Corymbia in the nursery and in young plantations was demonstrated, estimations of the heritability of resistance suggest that efforts to enhance this trait through breeding have reasonable prospects for success.