Effect of salinity on the growth, biological activity and secondary metabolites of some marine fungi

The study investigated the effects of salinity on growth,antimicrobial activities and secondary metabolites of 47 marine filamentous fungi isolated from the East China Sea near the western shore of the Taiwan Straits.The results indicate that NaCl promoted the growth up to 91.5% of test strains.However,only 14.9% of them showed a significant increase of antimicrobial activity against Candida albicans.When incubated in different concentrations of NaCl,the colony growth, antimicrobial activities and composition of secondary metabolites of the strain Ty01b-8 of Penicillium sp.varied.Treatment with KCl also showed a similar effect.An alkaloid isolated from the fermentation broth of Ty01b-8 was identified as chrysogine,inhibition activity of which against Hela cells was 15.05% at 20 μ g/ml,and yield was 4.4 and 4.9 times higher in 3 percent and 6 percent NaCl treatments,respectively, compared with the non-salt culture condition. These findings prove that salinity is an important factor influencing growth and secondary metabolites of some marine fungi,which can be used to screen for new metabolites from marine fungi,and to enhance their metabolites production in industrial fermentation.     

全球人口增长及其地质环境变化

论述了全球人口及城市人口增长与发展的基本规律，根据历史记录数据建立了其预测指数方程，预测结果表明，２１世纪５０年代全球人口将超过１００亿；且其城市人口将于２０２５年发展为７９亿。论证了人口高速增长与全球地质环境变化紧密相关。讨论了农业地质环境变化－谷物供应问题以及可耕土地资源减少和水土资源流失、沙漠膜问题及工业矿产、能源、资源与水资源紧缺以及其地质环境变化问题。相应于地质环境变化问题建立了预测方程     

Pedogeochemistry of china and its significance in agricultural production

Ｓｏｉｌｉｓａｎｅｐｉｇｅｎｅｔｉｃｓｐｈｅｒｅｈａｖｉｎｇｔｈｅｄｅｎｓｅｓｔｂｉｏｌｏｇｉｃａｌｍａｓａｎｄｔｈｅｈｉｇｈｅｓｔｂｉｏｌｏｇｉｃａｌｅｎｅｒｇｙ,ｗｈｉｃｈｉｓａｂａｓｅｍｅｎｔｐｒｏｖｉｄｉｎｇｔｈｅｐｌａｎｔｗｉｔｈｗａｔｅ...     

我国近40年温度的变化及对农业生产的影响

利用１９５１－１９９０年全国大体分布均匀的３５０个站点的温度资料，分析了近４０年年平均气温，最冷月，最热月平均气温的时空分布特点及各时段（以１０年为一时段）温度距平场的变化。并分析了温度变化对农业生产的影响。     

山东东部晚中生代构造岩浆活动及原型盆地恢复

山东东部近海地区花岗岩及变质岩中出露一套由陆源碎屑岩、火山碎屑岩和火山熔岩组成的沉积地层,其形成时代、地层属性及沉积背景争议较大。文中选取了青岛崂山垭口、灵山岛、唐岛湾,五莲大尚庄,诸城山东头村等剖面进行了详细的地层沉积特征描述,并对灵山岛老虎嘴处流纹岩及崂山垭口凝灰质铝土岩进行LA ICP MS测年,获得锆石U Pb年龄分别为(119.2±2.2)和(118.9±3.3) Ma,恰好对应胶莱盆地青山群火山活动初始阶段。根据沉积构造特征推断,山东近海晚中生代存在一个规模较大的NE向展布的裂陷盆地,呈凹隆相间的构造格局。系统总结了山东东部地区晚中生代构造岩浆活动及区域构造应力场的演化,发现裂陷盆地与胶莱盆地具有很好的对比性,莱阳期两盆地相连通,青山期由沿五莲青岛、牟即断裂带分布的火山弧将两个盆地分割,并对近海裂陷盆地晚中生代原型盆地进行恢复。     

对加快开发赣北某复杂类型金矿的几点认识

本文针对赣北某复杂类型金矿目前勘查及民采现状,认为进一步扩大勘查范围,提高勘探程度,才能为下一步矿区开发提供资源保证,文中还着重介绍了近年来矿区民采活动所取得的一些成功经验,对如何加快开发该金矿谈了几点认识。     

发展乡村科学,助力乡村振兴——第二届乡村振兴与乡村科学论坛综述

2019年4月27日,第二届乡村振兴与乡村科学论坛在南京成功举行,来自全国20多个省份的近400名专家学者相聚南京师范大学,共话乡村振兴战略与乡村科学发展。本次论坛共有8个特邀专家主题报告,14个议题报告,并设置了自由讨论环节。论坛报告及专家发言观点纷呈、讨论热烈。本文从乡村科学与乡村振兴、城乡融合与乡村振兴、精准扶贫与乡村振兴、深化改革与乡村振兴、乡村重构与乡村振兴、村域发展与乡村振兴等6个方面对主要观点进行梳理,以期对新时代乡村科学的快速发展与乡村振兴的有序推进有所裨益。     

气候变化对中国农业生产的影响研究进展

气候变化已成为当今科学界、各国政府和社会公众普遍关注的环境问题之一,气候变化可能对生态系统和社会经济产生灾难性影响,农业是受气候变化影响最直接的脆弱行业。因此,气候变化对农业生产的影响研究一直是气候变化研究领域中的热点问题之一。该文系统介绍了有关全球气候变化对中国农业生产影响研究的现状与进展,包括气候变化对农业影响的研究方法、大气中温室气体浓度增加对农作物的影响试验、气候变化对农业气候资源的影响、气候变化对农作物生长发育和产量的影响、气候变化对农业种植制度和品种布局的影响、气候变化对农作物气候生产潜力和气候资源利用率的影响等,指出当前在研究气候变化对农业影响评估中存在的问题,提出了今后应加强对气候变化情景和预测模式不确定性的研究、气候变化对农业影响的方法研究。此外,气候变化背景下极端天气气候事件对农业生产的影响以及气候变化对农业病虫害的影响研究等仍较薄弱,有待进一步加强和深入。     

Impacts of Non-farm Employment of Rural Laborers on Agricultural Land Use: Theoretical Analysis and Its Policy Implications

During rapid urbanization and industrialization process, non-farm employment of rural laborers has emerged as a prevalent phenomenon in rural areas of China and become an important driving factor for changes in agricultural land use. This article attempts to theoretically analyze the impacts of non-farm employment of rural laborers on agricultural land use based on economic frameworks. As rational agents, farmers aim to maximize their income and follow equilibrium principles when they decide how to allocate their labor forces (or working time) in two departments (farm and non-farm) and how to use their agricultural land with different quality and location. The income earned by non-farm employment is higher, and there exists a comparative advantage between labors, as a result the quantity and quality of labor input in agricultural land use decreases. With the limitation of labor input during agricultural land use decision-making of farm households, on the one hand, land with higher quality is still utilized by farmers. On the other hand, poor quality land will be less well managed and is more likely to be abandoned. Non-farm employment of rural laborers and the rising of opportunity costs will result in abandonment of poor quality land, and great importance should be attached to this by policy makers.     

宜昌县开拓农业企业的初步尝试

本文以宜昌县的实践为依据,论述了农业企业在振兴山区经济中的特殊地位和作用,并总结出“按规模经营组织山地开发,按农业企业特点实施管理,按商品生产需求搞好服务”的山地开发经验;指明兴办农业企业是一条振兴山区经济的成功之路。