农田土壤磷的环境指标研究进展

为了研究农田土壤磷的环境指标,综述了国内外1984—2014年农田土壤磷的环境指标研究,发现对于农田土壤磷的环境指标研究不断深入,虽然起步晚,但是进展较快。从研究农田土壤磷的流失途径和流失形态着手,发现土壤水溶性磷、颗粒态磷等不同形态的有效磷含量与地表径流中的磷含量呈现显著相关,流失至水体的磷含量与土壤Olsen-P含量具有较高的相关性,把土壤Olsen-P作为农田土壤磷的环境指标具有准确性及可靠性。综述国内外农田土壤磷的环境指标研究表明:目标水体为湖库和河流的土壤Olsen-P环境阈值分别为25 mg/kg和75 mg/kg。超过该临界值时,土壤径流、排水和渗漏液中磷含量将明显增加,加大农田中土壤磷进入水体的风险,造成水体富营养化,对水环境产生破坏。农田土壤磷的环境指标研究还存在不足,今后还需要研究农田土壤磷素在流失过程中的削减系数,以及农田土壤磷素通过地表径流与土壤侵蚀淋溶之间的交互作用机理。     

19个平菇品种子实体蛋白质和多糖含量研究

[目的]比较19个平菇品种营养值的差异。[方法]对供试的平菇19个品种进行子实体栽培,收集第一潮子实体,样品经过组织前处理,利用二奎林甲酸（BCA）检测法和苯酚-硫酸法测定子实体中的蛋白质和水溶性多糖含量。[结果]19个品种中,蛋白质含量最高的品种为黑丰268,占子实体鲜重的5.99%,其次是新育2000和平菇9906,分别占子实体鲜重的5.453%和4.594%,经与其他品种比较均达到显著性差异,这3个品种为蛋白含量筛选中的优势菌株;平82号和平12号的水溶性多糖含量较高,分别占子实体干重的2.806%和2.274%,经与其它品种比较均达到显著性差异,为水溶性多糖筛选中的优势菌株。[结论]不同品种的平菇中蛋白和多糖含量存在较大差异,可根据开发需要对其进行深加工方向的研究。     

江永香柚不同发育时期果皮分泌结构及油体的观察

利用冰冻切片法和组织化学方法对江永香柚不同发育时期果实的果皮进行显微结构、分泌组织和油体的观察,结果发现:授粉后发育至70 d左右的江永香柚果实,其果皮为绿色,外果皮细胞内含大量叶绿体。发育70~150 d的果实其果皮逐渐由绿色转变为黄色,外果皮细胞内叶绿体分布逐渐减少。柚果实外果皮有分泌结构(精油腔)散布在外果皮中,精油腔由两个肾形细胞包围而成,精油腔空隙含有较多的油体。外果皮细胞内有黄色油体的分布,与同属的橙果实外果皮中相比,油体体积大,数量少。     

Spectral effects on embryogenesis and plantlet growth of Oncidium ‘Gower Ramsey’

Embryogenic calli of Oncidium were grown under tubular fluorescent lamp (FL) or light-emitting diode (LED) arrays with different spectra to determine the effects of light quality on protocorm-like body (PLB) formation and plantlet growth from the callus. The effect of light is generated by monochromatic blue, red or mixed far-red LEDs on the photomixotrophic radiation. The light sources induced higher number of PLB formation compared with the darkness. The best condition for PLB formation was to culture on MS half salt medium supplemented with 0.1 mg l⁻¹ NAA and 0.4 mg l⁻¹ BA under red + blue + far-red (RBFr) LEDs and FL radiation for 8 weeks. Roughly 3000 embryos were induced in an initial culture of 1 g of fresh weight of calluses. During subculturing, PLBs had the ability to convert into plantlets. In this study also indicated the far-red LED radiation was a noticeable factor. It showed that using Fr combined with R and B (RBFr) or RFr radiation significantly enhanced leaf expansion, numbers of leave and root, chl contents, fresh and dry weight of Oncidium plantlets. Therefore, the wavelength specificity of RBFr LEDs comprising a novel illumination system is advantageous over FLs for PLB formation, resulting in higher efficiencies of plant regeneration and growth in Oncidium cultures.     

羊肚菌菌丝间融合与不融合现象研究

用平板、空试管、断培养基等方法培养羊肚菌菌丝,在显微镜下原位直接观察菌丝间的融合和非融合现象。观察六妹羊肚菌Morchella sextelata、梯棱羊肚菌M. importuna、七妹羊肚菌M. septimelata、Mel-21和秋天羊肚菌M. galilaea、Mes-16、Mes-19、Mes-20、Mes-21等9个物种,共100多个菌株菌丝间2 000多个接触点;并历经6年时间,用300多个菌株在国内外100多个地点超过500公顷面积进行出菇试验。结果发现:同一单孢菌株的菌丝分枝间有少量部位的可自体融合,融合点不产生新的分枝菌丝;同一物种的不同单孢菌株间菌丝不融合,同一物种的多孢菌株培养物内部相互不融合;不同物种间的菌丝都不融合;不融合的菌丝接触点出现Ⅱ型、X型、Y型、T型、π型等状况交叉而过,细胞接触而不融合;未见菌丝间的有性融合;菌丝接触后出现死亡、缠绕、卷曲、打结、膨大等现象;羊肚菌菌丝体纯培养物可以形成分生孢子和菌核。出菇试验结果表明,腐生型羊肚菌物种的出菇率,超过200个单孢菌株100%,超过100个多孢菌株100%,超过50个纯组织分离物小于50%,超过30个组孢混合菌株小于50%;出菇菌株在形态和产量有显著差异。共生型羊肚菌的菌种都不出菇。能出菇的同一物种的多孢菌株出菇后表现出子实体形态多样性,不同物种混合播种后出菇的子实体为原来物种的形态特征。结论:羊肚菌单孢培养物菌丝间不发生有性融合,单个孢子自身可孕,完全能够单孢出菇。     

Micropropagation of orchids: A review on the potential of different explants

Orchids are among the most diverse of the flowering plant families, with over 800 described genera and 25,000 species. Orchids are prized for their beautiful long lasting flowers exhibiting an incredible range of diversity in size, shape and colour. Today growing orchids is more than just a hobby, it is an international business covering around 8% of the world floriculture trade and has the potential to alter the economic landscape of a country. Large-scale multiplication of exquisite and rare hybrids using tissue culture techniques has helped orchids occupy a position as one of the top ten cut flowers. As orchids are outbreeders, their propagation using seeds leads to the production of heterozygous plants. Hence, protocols providing regeneration from various vegetative parts of the plants are needed. Though orchid micropropagation has shown spectacular development in the recent years, the wide spread use of micropropagation is believed to be still limited due to problems like exudation of phenolics from explants, transplantation to field, somaclonal variation etc. We endeavour to include the major investigations on explant-based orchid tissue culture starting from the pioneering works of Rotor [Rotor, G., 1949. A method of vegetative propagation of Phalaenopsis species and hybrids. Am. Orchid Soc. Bull. 18, 738–739] followed by Morel [Morel, G., 1960. Producing virus-free cymbidiums. Am. Orchid Soc. Bull. 29, 495–497] and Wimber [Wimber, D.E., 1963. Clonal multiplication of cymbidiums through tissue culture of the shoot meristem. Am. Orchid Soc. Bull. 32, 105–107] to date.     

铁皮石斛原球茎悬浮培养及其多糖积累的研究

将利用铁皮石斛种子诱导的原球茎在液体条件下培养,研究植物激素和有机添加物对原球茎增殖以及多糖积累的影响。结果表明,在N6液体培养基中附加1.0mg/L NAA+1.0mg/LKT+5%香蕉汁提取物+5%土豆汁提取物,最有利于铁皮石斛原球茎增殖和多糖积累,培养30d时,原球茎鲜质量达到122.9g/L,多糖含量在25d时达到24.2%。结果提示,利用液体培养规模化生产铁皮石斛原球茎是可行的,是铁皮石斛大田传统栽培方式的重要替代途径。     

我国农业面源污染过程模拟的困境与展望

我国农业面源污染依然严重,模型是面源污染防控决策支持的有效工具。本文在农业面源污染模型分类的基础上,系统梳理了各类模型在田块流失过程、流域迁移消纳过程中的构建方法。在田块产流过程模拟中,模型大多采用单一超渗或者蓄满产流机制;在流域迁移过程的消纳过程模拟中,迁移路径基于D8算法,采用固定的消纳系数模拟迁移过程中的消纳量。基于我国面源污染产生的特点,本文进一步总结了上述模型在我国农业面源模拟过程中的困境：在田块流失过程中,在我国旱地与水田并存情况下需同时考虑两种产流机制,在南方水域面积大的区域还需考虑农田氨挥发近距离沉降;在地表迁移过程中需考虑多地形（丘陵和平原）、多水体分布特点,地下迁移过程需考虑生物地球化学滞留和水文滞留过程。针对上述困境,文章展望了我国面源污染模型可能的解决方案,以期为我国农业面源污染模型的轻简化和高精度发展提供借鉴。     

基于GIS的青南高原自然灾害综合区划研究

本文根据青南高原地形、地貌、气候等自然地理要素及2002年人口、经济等社会人文要素和1949-2000年自然灾害统计数据与相关文献,运用ARCGIS 9.0及ARCVIEW 3.2软件建立青南高原自然灾害综合区划空间数据库及属性数据库并生成区划基本单元,运用自下而上区域合并的方法得到青南高原自然灾害区划小区,结合自上而下区域划分的方法将青南高原自然灾害划为4个一级灾害区10个二级灾害区,得到青南高原自然灾害综合区划方案。     

Splenic Hemangiosarcoma in a Young Sprague-Dawley Rat

The present report describes a rare case of spontaneous hemangiosarcoma in a nine-week-old male Sprague-Dawley rat. At necropsy, multiple white nodules of various sizes were observed on and within the enlarged spleen and liver and were histopathologically determined to be composed of spindle- to oval-shaped cells that showed invasive growth without encapsulation and were arranged solidly but partially in whorls or faint alveolar patterns with vascular-like spaces containing small clefts or erythrocytes in the tumor mass. Immunohistochemical analysis revealed that most of the tumor cells were strongly positive for vimentin, von Willebrand factor (vWF) and CD34 but negative for podoplanin. In addition, electron microscopic examination revealed the presence of Weibel-Palade bodies in the cytoplasm of the tumor cells. Based on these findings, this case was diagnosed as a hemangiosarcoma. The splenic masses were larger than the hepatic ones, with tumor cells mainly observed at periportal regions with tumor embolism in the liver, suggesting that primary hemangiosarcoma initially developed in the spleen before metastasizing.