富钾硅复合物的农业化学行为研究

富钾硅复合物中硅、钾、钙、镁养分的可溶性含量很高,但其有效态的养分含量却相对较低,故其养分只能缓慢地释放出来。在5个月的贮存过程中,多元复合物的水分含量对其养分的有效性没有明显的影响,但其养分含量却经历了一个明显的变化过程,其中可以用Freundlich方程拟合钾、镁的变化规律。多元复合物中硅、钾、钙、镁4种养分元素的释放速率随时间的延长而逐渐下降。     

中国东部主要农田土壤有机碳库的平衡与趋势分析

根据田间测定的有机物料腐殖化系数和土壤有机碳矿化量结果 ,以及统计测算的有机物质进入量 ,分析了中国东部主要农业区农田土壤有机碳库的平衡状况 ,并对其作为大气CO2 的源汇功能进行了初步评价。结果表明 ,各农业区农田土壤中有机物料腐殖化系数的变化趋势为 :松嫩平原 (作物秸秆 0 3 7,作物根 0 47,绿肥 0 2 6 ,粪肥 0 5 4 ) >红壤丘陵区(相应值为 0 2 8,0 45 ,0 2 5 ,0 42 ) >下辽河平原 (相应值 0 3 5 ,0 3 9,0 2 2 ,0 3 3 ) >黄淮海平原(相应值 0 2 5 ,0 3 2 ,0 1 8,0 2 7)。各区间的腐殖化系数并不随气候而呈规律性变异 ,而主要是环境因子综合作用的结果 ,特别是土壤性质有显著影响。现实有机物质进入量条件下 ,各农业区农田土壤有机碳年形成量分别为 :松嫩平原 5 3 8 0kghm- 2 ,下辽河平原 6 79 7kghm- 2 ,黄淮海平原 76 0 7kghm- 2 ,红壤丘陵区 1 0 5 9 7kghm- 2 ;农田土壤有机碳年矿化量分别为 :松嫩平原 90 5 3kghm- 2 ,下辽河平原 72 3 5kghm- 2 ,黄淮海平原 72 3 1kghm- 2 ,红壤丘陵区 782 9kghm- 2 。因此 ,松嫩平原黑土的有机碳库处于亏缺状态 ,土壤有机碳含量还将下降 ,并向大气释放CO2 ;红壤水稻土的有机碳库处于盈余状态 ,土壤有机碳含量还将不断提高 ,是大气C     

垄作免耕下稻田土壤团聚体和水热状况变化的研究

本文研究了垄作免耕下稻田土壤团聚体和水热状况的变化.结果表明:垄作免耕下的稻田土壤,<0.01mm土粒团聚度有增大的趋势,其中>0.01mm无机微团聚体和>0.01mm级铁、铝-有机微团聚体所占的比例表现为不同程度的提高,而>0.01mm级钙、镁-有机微团聚体显著下降;土壤水热状况处于新的协调状况促进了土壤潜在肥力的发挥.     

丛枝菌根真菌对青稞生长发育及磷营养的影响研究

青稞是大麦类作物中的一种，是西藏地区栽培面积最大、产量最多、分布最广的农作物品种。近年来，青稞的保健作用（富含-β葡聚糖和“生育三烯酚”）已得到国内外公认，因而青稞生产受到更广泛的关注。然而，根据西藏首次土壤资源调查结果，全自治区低磷（速效磷〈10mgkg^-1）土壤占总耕地面积的46．9％～72．3％（内部资料）。土壤供磷不足是限制青稞高产的重要潜在因素之一，同时西藏目前没有一家化肥厂，生产、科研所需肥料全靠从内地长途运输。寻找一条经济有效的途径缓解西藏地区农业生产肥料紧缺的状况成为一项迫切的任务。     

抗滑结构试验系统的探讨

本文针对我国抗滑结构发展的需要,提供了一个具有中等规模的抗滑结构试验系统的初步方案和模式,并论证了一种供滑坡抗滑结构实验系统的结构体系及结构试验系统的内容和程序。     

Protective effect of a new amide compound from Pu-erh tea on human micro-vascular endothelial cell against cytotoxicity induced by hydrogen peroxide

A new amide, N-(3,4-dihydroxybenzoyl)-3,4-dihydroxybenzamide (1), was isolated from the Pu-erh tea made with the leaf of Camellia assamica (Mast.) Chang by special fermentation techniques with bacteria and fungus. Its structure was established by means of spectroscopic data analyses, including mass spectrometry and both 1D and 2D NMR spectroscopy. Human micro-vascular endothelial cell (HMEC) injured with H₂O₂ was used as the model to test protective effect of compound 1 in contrast with other known compounds isolated from Pu-erh tea. These results suggested that compound 1 is a very useful compound to prevent H₂O₂-induced cell death of HMEC.     

Effects of salt-alkali stress on active oxygen metabolism in roots of Spiraea × bumalda ’Gold Mound’ and Spiraea × bumalda ’Gold Flame’

Under artificially-simulated complex salt-alkali stress, the levels of active oxygen metabolism in roots were studied using three-year-old cutting seedlings of Spiraea × bumalda ’Gold Mound’ and Spiraea × bumalda ’Gold Flame’. The present study aimed at exploring the antioxidant capacity in roots of spiraeas and revealing their adaptability to salt-alkali stress. Results indicate that the oxygen free radicals contents, electrolyte leakage rates and MDA contents in roots of Spiraea × bumalda ’Gold Mound’ and Spiraea × bumalda ’Gold Flame’ show an increasing tendency with the increases of the salinity and pH value, whereas the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) all increased firstly and then decreased. With the increase in intensity of salt-alkali stress, the CAT activity in roots of Spiraea × bumalda ’Gold Flame’ is higher and the increasing extents in the oxygen free radicals contents, electrolyte leakage rates as well as MDA contents are lower compared with Spiraea × bumalda ’Gold Mound’, indicating that Spiraea × bumalda ’Gold Flame’ has a stronger antioxidant capacity.     

油松毛虫成虫迁飞特性的研究（Ⅱ）──实验种群迁飞的模拟试验

利用昆虫飞行数据微机采集分析系统研究油松毛虫成虫飞翔能力，模拟测试结果的分析表明：油松毛虫成虫具有一定的飞翔能力，但雌雄蛾飞翔能力差异很大，雄蛾的飞翔能力及可飞翔的日龄均高于雌蛾；不同龄期成虫的飞翔能力亦不同，其中１～３日龄为最适飞行阶段。基于上述分析结果，用逐步回归等数学方法，建立了反映油松毛虫成虫飞翔能力的数学模型。     

A membrane-anchored protein kinase involved in Brassica self-incompatibility signaling

Self-incompatibility (SI) response in Brassica is initiated by haplotype-specific interactions between the pollen-borne ligand S locus protein 11/SCR and its stigmatic S receptor kinase, SRK. This binding induces autophosphorylation of SRK, which is then thought to trigger a signaling cascade that leads to self-pollen rejection. A recessive mutation of the modifier (m) gene eliminates the SI response in stigma. Positional cloning of M has revealed that it encodes a membrane-anchored cytoplasmic serine/threonine protein kinase, designated M locus protein kinase (MLPK). Transient expression of MLPK restores the ability of mm papilla cells to reject self-pollen, suggesting that MLPK is a positive mediator of Brassica SI signaling.     

祁连山森林土壤碳的初步研究

对祁连山森林土壤容重及碳贮量研究表明：祁连山森林土壤总贮碳１０４４．５万ｔ，并且呈增加趋势，对大气ＣＯ２通过森林起“汇”的作用；乔木林土壤对大气ＣＯ２的现实作用大，灌丛林潜在作用大；人类经营活动通过影响凋落物的凋落和分解，对土壤碳产生较大的影响。