春季栽培甜玉米品种鄂甜玉6号的种植密度筛选试验

为了研究春季栽培时,不同定植密度对甜玉米品种鄂甜玉6号主要农艺性状、产量及品质的影响,对2800、3200、3500、4000株／667m^2 4个种植密度进行了比较试验,结果显示,春季栽培时3200～3500株／667m^2为鄂甜玉6号最适宜的种植密度．其产量较高。     

Long-term nutritional effects on the primary liver and kidney metabolism in rainbow trout (Oncorhynchus mykiss). II. Adaptive response of glucose 6-phosphate dehydrogenase activity to high-carbohydrate/low-protein and high-fat/non-carbohydrate diets

The influence of long-term administration of high-carbohydrate/low-protein and high-fat/non-carbohydrate diets were studied in relation to kinetic behaviour of glucose 6-phosphate dehydrogenase in liver and kidney of rainbow trout. In all cases studied, the saturation curves of these enzyme showed typical hyperbolic kinetics without evidence of sigmoidicity. After 30 days of feeding with a high-fat diet (170 g kg^?1), there was a significant decrease in V_max and specific activity (45%) as well as catalytic efficiency (39%) without changes in K_m or activity ratio of hepatic glucose 6-phosphate dehydrogenase. These changes agree more with a clearly decreased cell concentration than with an inhibition of the pre-existing enzyme. The administration of a high-carbohydrate diet (60 g kg^?1), contrary to what was previously thought, decreased V_max by 21% and specific activity and catalytic efficiency by 30%, without significant changes in the other kinetic parameters of the hepatic enzyme. The kinetic behaviour under these nutritional conditons was due to the rejection of this diet by the fish and thus could be considered a low-feeding situation. On the other hand, no variations in the kinetics of renal glucose 6-phosphate dehydrogenase were found, clearly demonstrating that in this organ, the pentosephosphate pathway showed no adaptive response related to fattyacid and other lipid synthesis. The activity of the renal enzyme was consistently half that of the hepatic enzyme.     

6-BA对小麦开花期渍害的缓减效应

为了解6-苄氨基嘌呤(BA)对小麦开花期渍害的减缓效应,在大田条件下,于2012-2013和2013-2014年度,以郑麦9023为材料,研究了开花期喷施BA对小麦光合、干物积累及产量的影响。结果表明,开花期渍水使小麦两年分别减产51.4%和52.3%,减产的主要原因是千粒重和穗粒数降低,尤其是千粒重的下降,而穗粒数的减少主要归因于弱势粒的减少(两年分别减少21.4%和71.4%)。渍水前喷施6-BA处理比渍水处理显著增产,两年分别增产7.8%和31.6%,增产的主要原因是提高了千粒重和穗粒数。渍水前喷施6-BA可提高旗叶光合速率及SPAD值、干物质积累总量及收获指数,缓减旗叶及倒三叶衰老。说明渍水前喷施6-BA可通过促进小麦光合作用和干物质积累及其向籽粒的分配,减缓渍水对产量形成的不利影响。     

GA3和6-BA对降香黄檀种子发芽的影响

用两种植物生长调节剂GA3和6-BA不同药剂浓度（0、20、40、80 mg/L）和不同浸种时间（3、6、12、24 h）处理带果荚和去果荚的降香黄檀种子,结果表明：去果荚的种子用GA340 mg/L溶液浸泡12 h的发芽率最高,达到78%,壮苗指数和根冠比最优,效果最好。     

基于高分六号卫星红边波段的森林蓄积量遥感反演——以西宁市针叶林为例

红光波段和近红外波段常被作为森林蓄积量反演的敏感波段,介于两者之间的红边波段往往被忽略,为了明确红边波段对森林蓄积量的遥感反演精度的影响,本研究基于高分六号卫星宽幅影像（GF6-WFV）,结合西宁市2014年森林资源二类调查数据,从光谱特征、植被指数、地形因子、影像纹理等4个方面选取蓄积量反演的自变量,采用多元线性回归（MLR）、随机森林（RF）模型,分析比较了有无红边波段对西宁市针叶林蓄积量遥感反演精度的影响。结果表明：（1）无红边波段（No Red-Edge）和加入红边波段（Red-Edge Added）两组处理的纹理特征变量降维后,其主成分信息主要解释了红外、近红外以及红边1波段的纹理特征。（2）与蓄积量相关的光谱特征变量：No Red-Edge处理主要包括红边波段和近红外波段的地表反射率,Red-Edge Added处理主要为红边1波段的地表反射率;植被指数变量：No Red-Edge处理主要包括NDVI和SAVI,Red-Edge Added处理为MTCI。（3）加入红边波段后,RF模型的R²优于MLR模型,分别为0.6719和0.5487,RF模型的均方根误差（RMSE）小于MLR模型,分别为26.3m³hm⁻²和20.8m³hm⁻²。（4）去除模型对反演精度的影响后,相对于No Red-Edge,Red-Edge Added处理的反演结果与观测值拟合的R2提高了11.6%,RMSE降低了9.1%。说明加入红边波段可显著提高西宁市针叶林蓄积量的反演精度,研究结果可为森林蓄积量的遥感反演提供科学依据。     

Carbon Sequestration in Soil Humic Substances Under Long-Term Fertilization in a Wheat-Maize System from North China

The changes in humic substances （HS） is fundamental in detecting soil carbon sequestration mechanisms in natural and cultivated environments. Based on a long-term trial, the amounts of water dissolved substances （WSS）, humic acid （HA）, fulvic acid （FA） and humin （HU） were determined to explore the impact of long-term fertilization on HS. Increases in the amounts of WSS, HA, FA and HU were significant different among the treatments with manure. A significant correlation was found between the increased soil organic carbon （SOC） and HS （R^2=0.98, P〈0.01）. The change in the E4/E6 ratio was significantly correlated with the increased SOC （R2=0.88, P〈0.01）, HA （R^2=0.91, P〈0.01）, FA （R^2=0.91, P〈0.01） and HU （R^2=0.88, P〈0.01）. The cluster was mainly divided into two parts as manure fertilization and inorganic fertilization, based on the increases in HA, FA and HU. These results suggest that long term fertilization with manure favours carbon sequestration in HS and is mainly stabilized as HU, while the HA becomes more aliphatic. We conclude that increases in SOC can be linked to changes in the molecular characteristics of HS fractions under long term fertilization.