细胞膜质子泵在水稻耐铵机制中的作用机理探讨

 水稻是一种典型的耐铵植物。由于铵态氮营养条件会导致根系分泌大量的氢离子,对植物生长产生胁迫。因此,耐铵植物应具备耐酸的能力。细胞膜质子泵具有主动排出质子,调节细胞内外pH的功能。结合目前的研究结果,探讨了水稻根系细胞膜质子泵在铵态氮与低pH两个因素交叉作用下活性的变化及其调节机制,以阐明水稻耐铵的一个必要机制。上述结果对于丰富植物耐铵机制的研究具有重要的理论与实践意义。     

不同光谱能量分布对文心兰组织培养的影响

采用发光二极管(light emitting diode,LED)调制获取不同光谱能量分布的光源,以荧光灯为对照,研究其对文心兰原球茎诱导、增殖及生根组培苗生长的影响。结果表明:红光有利于原球茎的诱导,并促使原球茎产生最高的增殖系数和碳水化合物含量以及最低的分化出芽率;蓝光使原球茎产生最高的蛋白质含量、酶系活力和分化出芽率;单一红光促进文心兰生根苗茎的伸长,但不利于叶片色素的形成;单一蓝光抑制生根苗茎的伸长,促进叶片蛋白质和色素的合成;红蓝光谱分布处理的生根苗的生长量、干重、能效和酶系活力指标均高于荧光灯对照,色素含量与荧光灯对照无显著差异;红光LED促进文心兰原球茎的诱导,蓝光LED促进分化,红蓝光谱构成的LED光源更有利于生根组培苗的正常生长,是替代荧光灯的理想光源。      

棉花黄萎病菌的遗传多样性

阐明了棉花黄萎病的病原菌为大丽轮枝菌及其分类依据。从致病力分化、营养体亲和性分析、DNA分子指纹图谱比对等3个方面,对棉花黄萎病菌遗传多样性的研究进展进行了较为全面的综述。并对棉花黄萎病致病型与DNA分子标记多态性之间不存在显著相关性的原因进行了讨论。     

定西市安家沟小流域生态经济系统健康定量评价

从资源环境支持、经济支撑和社会人文影响三个方面选取19个因素作为参评因子,建立评价指标体系,对定西市安家沟小流域生态经济系统的健康状况进行了定量评价.结果表明:定西市安家沟小流域的生态经济系统的健康指数随时间均呈上升趋势,到2005年为止,资源环境的健康指数达到了0.599,已经进入了健康的良好阶段;社会人文的健康指数为0.545,也即将进入健康的良好阶段;只有经济支撑的健康指数为0.462,仍滞迟于健康的相对稳定阶段.该小流域从20世纪50年代治理以来,流域健康指数呈逐年上升趋势,由60年代的0.151增大到2005年的0.507,正向健康的良好阶段发展.     

高产抗倒广适冬小麦新品种石麦18号

介绍了石麦18号小麦品种的亲本组合、亲本特点、选育经过、主要特征特性、产量表现、突出优点、适宜区域和栽培技术要点。     

设施土壤连作障碍电处理试验研究

连作障碍是设施农业生产中的常见问题,严重影响着作物的产量和品质。目前,设施土壤连作障碍一般采用施肥或施药等化学方法对土壤进行消毒处理,但这样会造成土壤环境的二次污染,而利用电处理技术对土壤进行物理处理会避免这一问题。从土壤理化性质着手,以土壤中氮、磷、钾等营养元素含量为指标,通过试验研究及方差分析,验证电处理技术对土壤元素含量的变化有着显著的作用。     

增塑剂DEHP对土壤脲酶活性的影响

为科学合理地评价增塑剂DEHP的环境污染效应,通过室内模拟试验,研究不同浓度DEHP对土壤中脲酶活性的影响。试验结果表明,DEHP对脲酶活性的影响主要以抑制作用为主,抑制率随其浓度的增加而增大。米氏动力学方程拟合结果显示,脲酶活性对DEHP的污染不敏感,不能作为DEHP污染土壤的生态毒理学指标。     

Five methods to interpret field measurements of energy fluxes over a micro-sprinkler-irrigated mango orchard

Energy balance measurements were carried out in a mango orchard during two growing seasons in the semi-arid region of Brazil. The actual evapotranspiration (ET) was acquired by eddy correlation (EC) and Bowen ratio energy balance (BR) techniques. The daily energy balance closure in the EC measurements showed an average gap of 12%, with a root mean square error (RMSE) of 1.7 MJ m⁻² d⁻¹. Three different correction procedures were tested for closing the energy balance from the EC system: (1) the surface energy balance residual method (RES), (2) the Bowen ratio determined from the EC fluxes, the combination approach (EC_BR), and (3) a new regression energy balance closure technique (REG). All closing energy balance methods presented good correlation with the direct EC measurements, but the trends were not similar. The latent heat fluxes estimated by the BR method—λE _BR—were higher than those from the direct EC measurements—λE _EC. When using the RES method, the half-hour λE _EC measurements represented around 88% of the λE _RES values, as the uncertainties of net radiation—R _n—and soil heat fluxes—G—are propagated into the RES method. The latent heat flux derived from the combination approach—λE _{EC_BR}—also brings these uncertainties, being the agreements comparable with those for RES method. It was therefore concluded that a single correction method for EC measurements considering only the latent and sensible heat fluxes does not exist. A new way to solve the lack of energy balance closure from EC techniques was tested by means of a curve fitting, the REG method. Considering the REG corrections applied to the energy balance components involving all periods of the day and the average conditions of the two growing seasons, half-hour values of λE _EC were overmeasured by 18%, H _EC was undermeasured by 17%, and G values required a correction of 466%. The REG method appeared promising because it considers different weights for all energy balance components in the optimization process. Taking the REG results for the drier second growing season as a reference, it was concluded that seasonal ET values by the other methods in mango orchard ranged from 7 to 28% higher, showing that turbulent flux measurements lack accuracy for executing on-farm water-saving programmes and calibrating transient soil water flow models.     

水稻纹枯病菌对啶酰菌胺的敏感性测定

采用菌丝生长速率法测定了54株水稻纹枯病菌对啶酰菌胺的敏感性,建立了水稻纹枯病菌对该药剂的敏感基线。结果表明:啶酰菌胺对54个菌株的EC50值最小为0.4710μg/mL,最大为2.0607μg/mL,EC50均值为1.0603μg/mL;菌株敏感性频率分布呈单峰曲线,EC50均值可作为水稻纹枯病菌对啶酰菌胺的相对敏感基线。     

历史上羊楼洞茶业盛衰表象及原因分析

羊楼洞茶业起于唐,盛于宋,清末民初达到鼎盛,之后逐步衰落。茶区得天独厚的自然环境和区位优势为茶业发展提供了物质基础,随着全面饮茶之风的兴起,茶叶市场需求逐渐旺盛,加之宗教的影响,羊楼洞茶业蓬勃发展,主要表现在茶区扩大、名茶发展、茶政变迁、贸易兴起、出口扩张5个方面;但是随着政局动荡、外茶冲击、自身墨守陈规以及竞争上种种不利因素的影响,而逐渐走向衰落,主要表现在茶号衰落、茶园面积和贸易量下滑2个方面。