水稻适雨灌溉对稻田CH_4和N_2O排放的影响

采用静态暗箱-气相色谱法,观测分析了水稻适雨灌溉和常规灌溉2种模式下稻田CH_4和N_2O的季节排放情况,评估了水稻适雨灌溉对稻田CH_4和N_2O排放的影响。结果表明,适雨灌溉稻田CH_4、N_2O排放峰值分别出现在分蘖期和拔节孕穗期,整个生育期CH_4、N_2O平均排放通量分别为16.77 mg/(m~2·h)、6.64μg/(m~2·h),适雨灌溉稻田CH_4、N_2O排放量较常规灌溉显著下降(p0.05),分别下降了74.47%和67.06%。水稻适雨灌溉通过合理利用雨水资源,减少灌溉次数及灌水量,显著降低了稻田CH_4和N_2O的排放。     

棉花DUS测试标准品种的SSR指纹数据库构建

基于SSR核心引物,采用荧光毛细管电泳检测系统与多重PCR技术相结合,构建我国棉花DUS(Distinctness,Uniformity and Stability)测试标准品种的DNA指纹数据库并进行遗传多样性分析。依据多重PCR组合的基本原则与五色荧光检测系统的特点,采用40对核心引物构建了10个4重PCR组合,利用DNA遗传分析仪进行指纹检测与数据采集。40对荧光引物在30份DUS测试标准品种中共扩增产生146个等位变异,每对引物的等位变异数为2~7个不等,平均每对引物产生3.65个等位变异。海7124与陆地棉品种明显划分为2类,来源于新疆的新陆早1号区别于其他陆地棉品种,单独聚为1类。多色荧光检测系统相比常规聚丙烯酰胺凝胶电泳具有高精度、高通量、自动化程度高的优点,尤其适用于大规模指纹数据库的构建,提出了通过构建已知品种DNA指纹数据库,将分子标记技术应用于棉花DUS测试的初步设想。     

不同粒叶比小麦品种非叶片光合器官光合特性的研究

通过测定两个不同粒叶比小麦品种Lu 22和Lu 14叶片和非叶片光合器官叶绿素含量、光合速率及叶绿素荧光参数，探讨了非叶光合器官光合特性的差异。结果表明，高粒叶比品种Lu 22各部位的叶绿素含量均高于低粒叶比品种Lu 14，特别是在衰老后期，Lu 22能维持较高的叶绿素含量；在叶片叶绿素含量及光合速率明显下降时，非叶片光合     

水稻植株通气系统与稻田CH4排放相关性研究

水稻植株是稻田甲烷(CH₄)排放的重要通道,90%的CH₄气体由水稻植株通气组织排放到大气中。探讨水稻植株通气组织与水稻CH4排放量之间的相关性,可为水稻栽培和育种实践中减排CH₄提供理论和实践依据。2005年早、晚2季大田试验测定了16个水稻品种CH₄排放量和植株地上部各节间组织1     

根结线虫侵染对茄子叶片叶绿素荧光特性的影响

为了揭示根结线虫侵染对茄子叶片光合性能影响的原初反应机制,以‘紫阳长茄’为试材,采用盆栽幼苗人工接种方法,对根结线虫侵染期间茄子叶片叶绿素荧光参数的变化进行了研究。结果表明,随着根结线虫侵染时间延长,茄子叶片最大光化学效率(Fv/Fm)、实际光化学效率(ΦPSⅡ)、光化学猝灭系数(qP)持续降低,而非光化学猝灭系数(NPQ)则持续升高,并在接种15天时出现拐点,在此之前变化平缓,之后则变化剧烈,说明根结线虫侵染使茄子光系统Ⅱ(PSⅡ)反应中心遭受损伤。上述叶绿素荧光参数可作为茄子对根结线虫抗性的苗期鉴定指标,该方法简便、易行、高效、准确。     

基于激光诱导荧光高光谱技术无损检测脐橙表面敌敌畏残留

常规化学方法检测农药残留不仅对样品具有破坏性,而且费时费力。本文以激光诱导荧光结合高光谱图像技术为手段,对脐橙表面的敌敌畏农药残留进行光谱无损检测;实验方法是在脐橙表面,喷施用自来水配制的不同浓度的敌敌畏农药溶液,在实验室条件下风干后,采集激光诱导荧光高光谱图像,再用气相色谱法检测脐橙表面的农药残留量,应用偏最小二乘(Partial least squares,PLS)方法建立农药残留的预测模型,并找出最佳光谱区间,然后应用支持向量机(Support vectormachine,SVM)方法在最佳光谱区间的基础上建立农药残留的预测模型;所建模型结果其预测集样品的农药残留量实测值(0.4862~10.3791mg/kg)和预测值之间的相关系数为0.8101;实验结果说明,以激光诱导荧光结合高光谱技术为手段的无损检测技术,在检测脐橙农药残留方面是有可行性的。     

Oxidation of methane in the rhizosphere of rice plants

Oxidation of CH₄ in the rhizosphere of rice plants was quantified using (1) methyl fluoride, a specific inhibitor of CH₄ oxidation, and (2) measuring changes in plant-mediated CH₄ emission after incubation under air, N₂, or 40% O₂. No significant rhizospheric CH₄ oxidation was observed from rice plants in the ripening stage. CH₄ emission from rice plants 1 week before panicle initiation increased by 40% if CH₄ oxidation in the rhizosphere was blocked. The growth stage of the rice plant is an important factor determining the rhizospheric CH₄ oxidation. Fluctuation of rhizospheric CH₄ oxidation during the growing season may help to explain the observed seasonal CH₄ emission patterns in field studies. Measurements from four rice varieties showed that one variety, Pokkali, had higher rhizospheric CH₄ oxidation. This was probably because Pokkali was in an earlier growth stage than the other three varieties. Both in the early and in the late growth stages, incubation under N₂ caused a much stronger CH₄ flux than inhibition of CH₄ oxidation alone. Apparently, N₂ incubation not only blocked CH₄ oxidation but also stimulated methanogenesis in the rhizosphere. Incubation under a higher O₂ atmosphere (40% O₂) than ambient air decreased the CH₄ flux, suggesting that increasing the oxidation of the rice rhizosphere may help in reducing CH₄ fluxes from rice agriculture. The O₂ pressure in the rhizosphere is an important factor that reduces the plant-mediated CH₄ flux. However, inhibition of methanogenesis in the rhizosphere may contribute more to CH₄ flux reduction than rhizospheric CH₄ oxidation.     

Methane emission from two Indian soils planted with different rice cultivars

In a greenhouse study, methane emissions were measured from two diverse Indian rice-growing soils planted to five rice cultivars under similar water regimes, fertilizer applications and environmental conditions. Significant variations were observed in methane emitted from soils growing different cultivars. Total methane emission varied between 8.04 and 20.92gm^–2 from IARI soil (Inceptisol) and between 1.47 and 10.91gm^–2 from Raipur soil (Vertisol) planted to rice. In all the cultivars, emissions from IARI soil were higher than from Raipur soil. The first methane flux peak was noticed during the reproductive phase and the second peak coincided with the grain-ripening stage of the rice cultivars. Received: July 7, 1996     

浅谈推算和预测宏观尺度土壤N_2O释放量的方法

土壤是N2 O的最主要释放源 .本文综述了根据局部地区土壤N2 O释放观察结果 ,推算和预测宏观尺度土壤甚至全球土壤N2 O释放通量变化和年释放量的方法 ,评述了各类方法的优缺点 ;并着重讨论了释放过程机理模型的应用 .     

不同秸秆还田模式与氮肥施用量对土壤N2O排放的影响

以山东省桓台县为试验地点,分析在高产条件下,不同秸秆还田模式和氮肥施用量对农田N2O排放的影响.试验结果表明,氮肥施用量与秸秆还田模式都是影响土壤N2O排放的重要因素;小麦秸秆还田可以大大降低土壤N2O的排放,施用有机粪肥是影响N2O排放的另一重要因素.