Response of pea (Pisum sativum L.) to mepiquat chloride under varying application doses and stages

Grown as a monoculture, peas (Pisum sativum L.) exhibit severe lodging after flowering and lodging causes yield reductions considerable. This study was conducted to investigate the effects of dose (untreated, 25, 50, 75 and 100 g a.i. ha^?1) and stage (late vegetative, early blooming and early pod filling) of mepiquat chloride (MC) application on the growth, lodging control, seed yield and yield parameters of pea (Pisum sativum L.) under field conditions in Erzurum, Turkey in 2002 and 2003. Application doses of 25, 50, 75 and 100 g a.i. ha^?1 significantly reduced stem height by 5.3 %, 7.2 %, 7.5 % and 6.4 % and increased stem width by 7.5 %, 12.7 %, 12.3 % and 15.7 % respectively, when compared with the untreated control, and thereby reduced the tendency of the crop to lodging. Increases of the seed yield under different application doses of MC ranged between 13.7 % and 20.1 % over the untreated control. However, in all parameters investigated, except for stem width, higher application doses of MC gave no clear advantages compared with the application dose of 25 g a.i. ha^?1. Seed yield was also significantly influenced by application stage of MC and application at early blooming stage of crop, MC significantly increased seed yield by 11.4 % and 10.2 % when compared with the late vegetative and the early pod filling stages respectively. Furthermore, the interaction of application dose and stage was significant, and spraying of pea plants with 25 g a.i. ha^?1 MC at early blooming stage has the most beneficial effects on the characters evaluated.     

氯化钾缓解肉仔鸡热应激的研究

120只28日龄艾维茵(AVIAN)肉仔鸡随机分为1、2、3、4组.1组为对照组,饮自来水;2、3、4组为试验组,分别饮添加0.18％、0.26％、0.34％氯化钾的自来水.舍温控制在34±1℃.试验期为4周.结果,各组鸡增重、采食量、饲料效率、饮水量的顺序均为第4组→第3组→第2组→第1组.饮水中添加KCI,肉仔鸡血清K~ 浓度高于对照组,而直肠温度、呼吸率及血清尿酸浓度则相反.血清Na~ 前两周3、4组显著低于1组,以后趋于一致.血细胞压积(PCV)、血液PH、CO_2分压(PCO_2)、氧分压(PO_2)、碳酸氢根(HCO_3)和血清中总蛋白、白蛋白、白/球比以及血糖,组间均差异不显著.本试验表明,饮水中添加KCI能较好地缓解热应激对肉仔鸡生长的影响,增强肉仔鸡对高温的耐受性,并可提高其生产性能.     

氯化胆碱对烟草植株生长的促进效应

对烟草喷施不同浓度（０，５０，２００，３００，５００和１０００ｍｇ·Ｌ－１）的氯化胆碱（ＣＣ）后，可提高烟草的株高，尤其对茎粗生长、叶数和叶面积等有明显的促进作用。ＣＣ对增强烟草苗期根系活力和提高苗期的抗寒性也有明显作用。其中以喷施２００和３００ｍｇ·Ｌ－１的ＣＣ者对烟草生长的促进效果最大。     

氯化钠影响下蓝藻Anabaena 7120的固氮活性和去铵阻抑

正常培养液中NaCl浓度增高时,蓝藻固氮活性明显下降,去铵阻抑速率也减慢。NaCl浓度越高,阻抑程度越大。如果NaCl浓度过高,固氮酶活性即完全丧失,铵阻抑效应也不能消除。低光照度、光合抑制剂、O_2、N_2以及N_2+CO_2都加剧高浓度NaCl对蓝藻固氮酶活性和去铵阻抑的阻抑,而外源蔗糖、H_2和H_2+O_2则有一定程度的促进。     

Organic chlorine and chloride in submerged paddy soil: a case study in Anhui province, southeast China

Abstract. Efforts to understand the fate of organochlorine compounds in arable soil have concentrated on anthropogenic compounds, in spite of the fact that organochlorine compounds are both produced and mineralized in soil through natural processes. In order to understand the fate of chlorinated pesticides, it is necessary to take account of the natural chlorine cycle. The present study is a first attempt to illuminate the relationship between the natural chlorine cycle and agricultural practices. The concentration and storage of organic chlorine (Cl_org) and chloride (Cl_inorg) were determined in topsoil of a paddy field compared to an adjacent afforested hill at a sampling site in the Meicun area, Anhui Province, China. The concentration of Cl_org, as well as the chlorine-to-carbon ratio, was significantly lower in the paddy field samples than in the forest soil samples. A weak relationship between the concentration of Cl_org and the organic carbon content was observed in the paddy field, in contrast to the observations made in the adjacent forest soil as well as those made in previous studies, which have suggested a positive correlation between organic carbon content and Cl_org. The similarity between our results at the forest site and the previous studies, which have been carried out in temperate regions, suggests that it is the land use rather than the climate that makes the current paddy soil results different. Our results suggest that the contribution of Cl_org to the paddy soil from above-ground litter and from production within the soil are small or negligible compared with the contribution from pesticide application and wet and dry deposition.     

Drought and salinity: A comparison of their effects on mineral nutrition of plants

The increasing frequency of dry periods in many regions of the world and the problems associated with salinity in irrigated areas frequently result in the consecutive occurrence of drought and salinity on cultivated land. Currently, 50% of all irrigation schemes are affected by salinity. Nutrient disturbances under both drought and salinity reduce plant growth by affecting the availability, transport, and partitioning of nutrients. However, drought and salinity can differentially affect the mineral nutrition of plants. Salinity may cause nutrient deficiencies or imbalances, due to the competition of Na⁺ and Cl^– with nutrients such as K⁺, Ca²⁺, and NO . Drought, on the other hand, can affect nutrient uptake and impair acropetal translocation of some nutrients. Despite contradictory reports on the effects of nutrient supply on plant growth under saline or drought conditions, it is generally accepted that an increased nutrient supply will not improve plant growth when the nutrient is already present in sufficient amounts in the soil and when the drought or salt stress is severe. A better understanding of the role of mineral nutrients in plant resistance to drought and salinity will contribute to an improved fertilizer management in arid and semi‐arid areas and in regions suffering from temporary drought. This paper reviews the current state of knowledge on plant nutrition under drought and salinity conditions. Specific topics include: (1) the effects of drought and salt stress on nutrient availability, uptake, transport, and accumulation in plants, (2) the interactions between nutrient supply and drought‐ or salt‐stress response, and (3) means to increase nutrient availability under drought and salinity by breeding and molecular approaches.     

腰果酚基乙酸酯增塑剂的合成及其增塑聚氯乙烯性能

为了进一步利用农林剩余物资源替代石化原料,该研究以腰果酚为原料,通过对其酚羟基进行酯化改性,制备腰果酚基乙酸酯(cardanol acetate,CA)增塑剂。采用核磁共振氢谱(1H nuclear magnetic resonance,1H NMR)和核磁共振碳谱(13C nuclear magnetic resonance,13C NMR)对产物的结构进行表征。通过动态力学性能(dynamic thermo mechanical analysis,DMA),拉伸性能测试,热重分析(thermogravimetric analysis,TGA),以及与聚氯乙烯(polyvinyl chloride,PVC)共混样品的傅里叶红外分析(fourier transform infrared spectroscopy,FT-IR)等方法,评价腰果酚基乙酸酯作为辅助增塑剂应用于软质聚氯乙烯的增塑效果,并与商业增塑剂对苯二甲二辛酯(bis(2-ethylhexyl)benzene-1,4-dicarboxylate,DOTP)进行对比。研究结果表明,m(DOTP)∶m(CA)=4∶6为较佳配伍比例,共混体系的玻璃化转变温度由41.52℃降低至35.93℃,断裂伸长率由244.75%增加到了302.13%,热稳定性及相容性均得到有效改善,因此腰果酚基乙酸酯可用作聚氯乙烯的优良辅助增塑剂。研究结果为腰果酚在增塑剂领域的应用提供了参考。     

氯化钠不同浓度对夏玉米生长和吸氮的影响

采用珍珠岩为基质的温室盆栽试验,研究不同盐分(NaCl)水平对夏玉米生长和吸氮的影响。试验设灌溉水中NaCl浓度为0、10、20、40和60mmol.L5个处理。结果表明,在出苗后的25～101d(7月25日～10月10日),当NaCl浓度达到60mmol.L时,明显降低了夏玉米的叶面积、株高、干物质量和根长;盐分对植株体内各器官的氮含量影响不大。随着NaCl含量的增加,植株的总氮累积量将减少,且植株中累积氮量随时间呈二次函数增长。     

A non-ACC pathway for ethylene biosynthesis in Botrytis cinerea

Premature softening and tissue senescence occur in kiwifruit infected with Botrytis cinerea. While ethylene production is enhanced in infected fruit and B. cinerea produces ethylene on defined media in vitro the source of ethylene in this pathosystem is unclear. Ethylene production by B. cinerea was enhanced when methionine or ∝-keto-methylthiobutyric acid (KMBA) was added to a defined (modified Pratts) medium. Although 1-aminocyclopropane-1-carboxylic acid (ACC) did not stimulate ethylene production, ∝-aminooxyacetic acid (AOA) was inhibitory suggesting a role for a pyridoxal phosphate mediated enzyme reaction down stream from the methionine/KMBA stimulated ethylene biosynthetic pathway. Cobalt chloride (Co²⁺) was inhibitory, but after a 4-d lag period ethylene production from B. cinerea cultures containing methionine and Co²⁺ reached the same level as those without Co²⁺. [U ¹⁴C] methionine was converted to ¹⁴C-ethylene with high efficiency indicating that it is a direct precursor, while [2,3 ¹⁴C]-ACC did not yield radioactively labelled ethylene. These results suggest that the ethylene biosynthetic pathway in B. cinerea does not involve ACC as a precursor and that the enzyme responsible for synthesising ethylene is similar to, but different from, ACC oxidase from higher plants. The ethylene biosynthetic pathway in B. cinerea is yet to be determined.     

Boundary Element Method for Time-dependent Chloride Diffusion and the Chloride Distribution in Concrete

The process of chloride diffusion in concrete is time-dependent.The boundary element method (BEM) with a time-dependent diffusion coefficient is presented for chloride diffusion in concrete based on the suitable transformation of variables.The fundamental solution of the partial differential equation for time-dependent chloride diffusion in concrete is developed,and the compensation length of the diffusion field is defined as well as the compensation coefficient.The scheme of BEM with a time-dependent diffusion coefficient is developed.Two examples are given to demonstrate the accuracy and efficiency of the presented method and the rationality and the importance of the compensation length for the method.