Influence of soil temperature and moisture on micronutrient supply,plant uptake,and biomass yield of wheat,pea, and canola

Abstract

Crop yield response to micronutrient fertilization is difficult to predict, particularly under unfavorable environmental conditions as these may alter both crop nutrient demand and the soil micronutrient supply to plant roots. The research objective was to evaluate the effect of various soil temperature and moisture conditions on crop growth response to added micronutrient copper (Cu), zinc (Zn), and boron (B) along with soil micronutrient supply and distribution among fractions. Brown and Dark Brown farm soils collected from southern Saskatchewan were used to grown wheat, pea and canola within controlled environment chambers. The biomass yields of all crops decreased under cold soil temperature and moisture stress (drought and saturated) conditions. Greater plant uptake of Cu, Zn, and B was associated with optimum (i.e., field capacity) soil moisture and warm temperature (23°C) growing conditions, compared to drought (i.e., 50% field capacity), saturated, and cold (5°C) temperature conditions. Environmental stress had the greatest impact on pea growth, reducing crop yield and micronutrient utilization efficiency more than 95%. Soil supplies of Cu and Zn were most negatively impacted by drought stress due to reduced mobility of these diffusion limited nutrients. The extractable micronutrients levels and chemical speciation fractions of Cu, Zn, and B indicating that bioavailability and micronutrient transformation were not affected during our short-term (i.e., six-weeks) study. However, it is suggested that assessments of micronutrient forms also be conducted on soil samples under actual moisture and temperature conditions as they exist in the experiment, as well as on dried, processed samples.     

用32P示踪法研究昆明市水土流失的规律

应用32P研究山地水土在不同时间、坡度、方向、深度、距离的吸收和分布规律。结果表明:1g山地土壤对32P的吸收随着深度、距离的增加而减小。土壤对32P的吸收率的最大距离为3470.7969×10-5%,最小为1.2097×10-5%;最大深度为2407.9855×10-5%,最小为0.4752×10-5%。在坡度上,磷的吸收率呈波形变化,即在15°～30°,50°～80°时随坡度的增加而减小,在30°～40°时无明显变化,在40°～50°时随坡度的增加而增加。32P的吸收率与距离、坡度、方向呈显著负相关。     

Influence of microbial activity and soil moisture on herbicide immobilization in soils

Mobility, extractability, and disappearance of the herbicides diuron, terbuthylazine, metolachlor, and pendimethalin were examined in incubation experiments with two topsoil samples of different natural microbial activity and after sterilization. Soil moisture was held constant at 10, 40, and 60 % WHC. In other variants, the soil water content was changed during the incubation. The four herbicides reveal a fairly different extent of microbial and chemical degradation and immobilization. The herbicide mobility – expressed by coefficients of partition between adsorbed and dissolved herbicide amounts – decreases at a lower rate and extent, when the microbial activity is low or the soil is sterile. With increasing initial soil moisture, also herbicide mobility and extractability increase; but in the course of time, abiotic immobilization occurs to a higher extent. When soil moisture changes during the incubation, formerly non‐extractable herbicide fractions (up to 40 % of the applied amounts) become extractable. Kinetics of herbicide immobilization follow an empirical sigmoidal function, which describes three periods of immobilization. The three‐period shape of the curve and its possible reasons are discussed for the data of the incubation experiments as well as for the results of a long‐term field trial with diuron.     

抚顺煤矿西露天采场裸露岩石的污染潜势研究

利用净产酸量、净产酸势实验和连续化学浸取实验,研究了抚顺西露天采场裸露岩石的酸化潜势和重金属的表生活动性。结果表明,露天采场的裸露岩石在自然风化过程中会发生酸化,油母页岩属于中高度产酸范围,绿色泥岩、褐色泥岩处于低度产酸范围。原岩中Zn的潜在表生活动性最强,原岩中Zn含量的95%左右可被带出,进入表生环境;Cd,Cu,N i的潜在表生活动性有所差异,但原岩中Cd,Cu,N i含量的50%以上可被浸出进入表生环境;Pb的潜在表生活动性相对较小,只有20%的可被浸出进入表生环境。研究结果为预测煤矿开采环境污染的程度和防治提供了理论依据。     

家禽精子迁移率Mobility是反映家禽精液质量的重要指标

精子活率是精子的重要特性,传统精子活率的评价方法并不代表精子在家禽机体内生殖道的真实运动情况,具有主观性的特点,准确性差。精子迁移率Mobility的测定方法模拟精子在母鸡体内液体环境和温度下的运动情况,能够反映精子在体内真正的活力。从37只纯种白洛克公鸡中挑选出具有不同精子迁移率Mobility的高、低2组,每组5只公鸡,其精子迁移率分别为1.103,0.219,相应的受精率分别为83.7%、76.8%(P<0.05)。结果表明:精子迁移率Mobility反映了不同家禽个体精液质量的差异,是预测人工授精效果的一个重要指标。     

Effect of curcumin on learning-memory ability and expression of HMGB1 and JNK in rat model of Alzheimer disease

AIM: To evaluate the effect of curcumin on impaired learning-memory ability and the expression of high mobility group box protein 1 (HMGB1) and c-Jun N-terminal kinase (JNK) in a rat model of Alzheimer disease (AD). METHODS: Male Sprague-Dawley rats, weighing 250~270 g, were randomly divided into 4 groups (n=9): blank control group (group A), model group (group B), curcumin treatment group (group C, curcumin injected intraperitoneally at 100 mg·kg-1·d-1 for 6 consecutive days) and solvent control group (group D). The rats of AD model were induced by injection of ibotenic acid into the nucleus basalis of Meynert (NBM) bilaterally. All rats were trained in Morris maze to assess the ability of learning and memory. The expression of HMGB1 and JNK in the hippocampus was detected by the methods of immunohistochemistry and Western blotting. RESULTS: Compared with group A, the average escape latency (AEL) in groups B and D were obviously longer (P<0.05), while AEL in group C in the 5th and 6th days were significantly shorter (P<0.05). The releases of HMGB1 in the CA1 and CA3 areas in groups B and D from the nucleus were abundant. Compared with groups B and D, HMGB1 in hippocampal CA1 and CA3 areas in group C secreted out of the nucleus decreased obviously (P<0.05). No significant difference of the release of HMGB1 between group A and group C was observed (P>0.05). No significant difference in the expression of HMGB1 in the hippocampus among the 4 groups was found (P>0.05). However, compared with groups B and D, the expression of JNK in group C was decreased obviously (P<0.05). CONCLUSION: Curcumin significantly improves the learning and memory ability of AD rats. The probable mechanisms may be related to inhibiting the release of HMGB1 from the nucleus of hippocampal neurons and decreasing the expression of JNK in the hippocampus.     

转crylAh基因玉米花粉对龟纹瓢虫生长发育和成虫移动能力的影响

本文利用花粉饲喂法研究了转crylAh基因玉米花粉对龟纹瓢虫Propyleajaponica生长发育及成虫移动能力的影响。结果显示,与混有适量蚜虫的非转基因亲本对照玉米花粉（花粉与蚜虫重量比为2：1）相比,龟纹瓢虫幼虫取食混有适量蚜虫的转crylAh基因玉米花粉（花粉与蚜虫重量比为2：1）后,幼虫总发育历期、蛹期和成虫寿命均无显著差异,但l、3和4龄幼虫的发育历期显著高于对照,2龄幼虫的发育历期显著低于对照;2龄和4龄幼虫的存活率与对照无显著差异,但3龄幼虫的存活率显著增加;幼虫取食Bt花粉对该虫的蛹重、羽化率和雌雄比与对照无显著差异。幼虫期取食Bt玉米花粉而成虫期取食蚜虫对成虫的日产卵量无不利影响,与对照无显著差异。幼虫取食Bt玉米花粉羽化后雄虫和雌虫的步速和翻跃时间与对照均无显著差异。     

一种新的快速鉴定蛋白与靶DNA结合位点的方法

DREB转录因子在植物逆境胁迫响应中起非常重要的作用, 对植物的生长发育起重要的调控作用。传统的DNA酶I足迹法应用同位素标记DNA, 采用序列胶分离DNase I酶切片段, 操作较复杂, 分辨率较低, 不适用于高通量的样品检测。为阐明植物体内DREB转录因子的调控机制, 本研究利用改进的DNA酶I足迹法(DNase I Foot-printing)结合凝胶阻滞法(electrophoretic mobility shift assay, EMSA), 选用荧光色素代替同位素标记, 毛细管电泳技术代替序列胶检测DNase I酶切片段, 判定GmMYB1蛋白与GmDREB3启动子DNA结合的区域。采用限制性内切酶酶切GmDREB3启动子DNA验证以上结果。同时, 在判定的GmMYB1结合区域的基础上, 选择可能的DNA结合元件与GmMYB1进行EMSA试验, 证明GmMYB1可以与相应元件结合。该方法比传统的DNA酶I足迹法快速、简便、准确并可靠, 作为一种高通量的鉴定方法可用于大规模鉴定蛋白质的DNA结合位点。     

在人才流动中促进高校师资队伍建设

人才流动是社会主义市场经济发展的客观要求，对高等学校而言，这既是机遇，又是挑战。高等学校必须进一步深化人事管理体制改革，在人才流动中促进师资队伍建设。