枸杞幼苗对钒胁迫的生理响应和积累特性

在不同的钒（V）胁迫浓度（0、25、50、100和200 mg＆#183; kg -1）条件下,通过40 d盆栽试验,研究了枸杞植株对V积累及V对枸杞叶中细胞膜透性、抗氧化酶活性,以及丙二醛（ MDA）、脯氨酸（ Pro）、叶绿素和可溶性蛋白含量的影响。结果表明,枸杞中各部位V含量分布大小的顺序依次为根＞叶＞茎。随着V浓度增大,过氧化氢酶（CAT）和过氧化物酶（POD）活性、叶绿素含量和可溶性蛋白含量等呈先上升、后下降的变化趋势,当 V 胁迫浓度≤100 mg ＆#183; kg -1时,与对照组相比, CAT和POD的活性、叶绿素含量和可溶性蛋白含量分别增大了227.9％、76.2％、40.2％和117.4％;当V胁迫浓度＞100 mg＆#183; kg -1,则分别降低了5.1％、5.8％、22.8％和36.7％。在不同浓度V的处理下, MDA含量、细胞膜透性和 Pro 含量比对照分别增加了13.3％～220.7％、12.4％～76.9％和69.7％～276.3％。可见,低浓度V （＜100 mg＆#183; kg -1）刺激了叶绿素和抗氧化酶活性的增加,促进了植物可溶性蛋白质的合成;高浓度V （≥100 mg ＆#183; kg-1）破坏了叶绿素结构,抑制了抗氧化酶和可溶性蛋白的合成,膜脂过氧化作用和细胞膜透性显著增大,游离脯氨酸含量明显增加。     

二氧化硫污染损害水稻的定性与定量

研究了二氧化硫污染损害水稻的作用机制,水稻受二氧化硫污染可能出现的症状,二氧化硫污染大气监测,以及环保部门在处理此类污染赔偿案时如何定性与定量.     

Ecophysiological Effect of La-Gly on Soybean Harmed by Acid Rain

Ｔｈｅｈａｒｍｆｕｌｎｅｓｏｆａｃｉｄｒａｉｎｉｓｏｎｅｏｆｔｈｅｓｅｒｉｏｕｓｅｎｖｉｒｏｎｍｅｎｔａｌｐｒｏｂｌｅｍｓｏｆｔｈｅｍｏｄｅｒｎｗｏｒｌｄ．Ｃｈｉｎａｈａｓｂｅｃｏｍｅｔｈｅｔｈｉｒｄｌａｒｇｅａｒｅａｏｆａｃｉｄｒａｉｎｉｎｔｈｅｗ...     

UV-B辐射对豌豆伸长生长和细胞壁多糖组分的影响

为探讨紫外线-B（UV—B）辐射引起的豌豆幼苗生长抑制与细胞壁结构组分变化的关系,以豌豆幼苗为对象,研究UV—B辐射对豌豆幼苗株高、细胞壁多糖组分（包括果胶、半纤维素A、半纤维素B和纤维素）中总糖含量与醛酸含量的影响。研究结果表明：自然生长的豌豆幼苗,随着生长天数的增加,幼苗株高增加,但单位长度细胞壁多糖总量降低,两者呈显著负相关（p〈0．05）;UV-B辐射会抑制豌豆幼苗的伸长生长,从而提高了单位长度内细胞壁的多糖总量;在UV—B辐射第5天时,相比对照组,幼苗株高降低了7．35cm,细胞壁多糖增加0．07mg／cm。豌豆幼苗茎细胞壁果胶、半纤维素A、半纤维素B和纤维素中的总糖含量分别比对照提高了22．30％、42．30％、21．47％和12．05％;醛酸含量分别比对照提高6％、33．3％、17．24％和18．08％。提示UV-B辐射调节了细胞壁组分代谢,提高了细胞壁多糖组分总糖与醛酸的含量,使细胞壁增厚,这可能使细胞壁刚性增强、延展性降低,因而限制了细胞伸长生长,抑制了豌豆幼苗生长。     

烟草托盘育苗钵苗力学性能试验

为设计机械化取苗机构,以山东农业大学温室大棚培育的“革新一号”移栽期烟草钵苗为试验材料,在万能试验机上对烟苗进行了钵苗拔取、烟苗茎秆拉伸、压缩、弯曲和剪切力学性能试验。结果表明,营养基质含水率为（52.70±6.50）%时,烟苗拔取力为（2.09±1.28）N;烟苗茎秆含水率为（85.15±2.21）%时,烟苗茎秆抗拉强度为（1.96±0.68）MPa;烟苗茎秆径向抗压强度以及底部、中部的轴向抗压强度分别为（0.096±0.043）、（1.20±0.34）、（1.28±0.28）MPa;简支梁、悬臂梁弹性模量分别为（0.0042±0.0018）、（0.0130±0.0062）MPa;剪切强度为（1.64±0.39）MPa。此结果为机械化取苗机构的设计提供了理论依据。     

Growth response of rubber seedlings to N,P, and K fertilizer in Nigeria

A two-year study (1977/78 and 1978/79) was carried out using GT I seedlings raised in polybags at the Rubber Research Institute of Nigeria (RRIN) main station, to determine the response of rubber seedlings to the application of N, P, K fertilizer. The fertilizers were each applied at three rates as follows: 0, 45 and 90 kg N per ha as sulphate of ammonia; 0, 14.80 and 29.60 kg P per ha as single superphosphate and 0, 9 and 18 kg K per ha as muriate of potash. Stem diameter and height were measured at monthly intervals, while dry matter of tops was estimated at the end of each year of study. P emerged as the single most important nutrient followed by N and K in order of magnitude. Growth response to N and K were enhanced by the presence of P at both levels. The degree of response was related to the level of each nutrient in the soil. Best growth was obtained in the treatments containing all three nutrients. In conclusion, application of fertilizers to rubber seedlings on the soils used, is justified by the growth increases obtained, especially where all three nutrients were applied together.     

弱光下番茄穴盘育苗增施CO2的效应研究

在番茄穴盘育苗条件下,对不同弱光条件增施CO2的效应进行了研究。结果表明:即使采用了抑制徒长和提高秧苗质量的株型调控和增施CO2手段,重度弱光下不仅造成秧苗生育量的显著减小,且物质分配愈倾向于徒长,在轻度弱光下增施CO2,虽然不及正常光照下增施CO2的处理效果,但与正常光照下不施CO2处理相比还有一定的提高作用,也就是说,在轻度弱光下通过增施CO2可以弥补弱光对秧苗生长发育和物质分配造成的不良影响。     

不同种子药剂处理对小麦纹枯病控制效果和小麦苗情素质的影响

笔者通过设置不同的拌种剂处理小麦,得出药剂拌种后可有效控制小麦纹枯病的发生,其中31%苯醚·咯·噻虫表现较好。药剂拌种提高小麦的基本苗数和产量,增强了对逆境的抵抗能力,并提高了后期的小麦的成穗数。因此,这类药剂的使用既增加产量又提高抗病虫害能力。     

Effect of Lanthanum （Ⅲ） on Reactive Oxygen Metabolism of Soybean Seedlings under Supplemental UV-B Irradiation

The effect of lanthanum （Ⅲ） on reactive oxygen metabolism of soybean seedlings under elevated ultraviolet-B radiation（UV-B：280~320 nm）at 0.15 and 0.45 W·cm-2 levels respectively was studied through hydroponics in the laboratory.Plasmolemma permeability and contents of malonadialdehyde（MDA）,hydrogen peroxide（H2O2）,and proline gradually increased during the imposition of UV-B radiation and subsequently decreased during recovery from UV-B stress.The dynamic tendency of catalase（CAT）activity was similar to that of the above four indices.The activity of peroxidase（POD）initially increased,then remained at a high level,and finally dropped steeply when soybean seedlings were exposed to a low dosage of UV-B radiation.However,POD activity rose throughout and declined slightly on the eleventh day when soybean seedlings were stressed by a high dosage.With the addition of La （Ⅲ） of 20 mg·L-1,the rising tendency of plasmolemma permeability and contents of MDA,H2O2,and proline were slowed down during the stress period,whereas the declining speed was accelerated during the recovery period.The activities of CAT and POD were higher than those without La （Ⅲ） in all experiments.It suggested that the regulative effect of La （Ⅲ） on antioxidant enzymes such as CAT and POD could strengthen their capacities to scavenge reactive oxygen species（ROS）,decrease contents of MDA and proline,and maintain normal plasmolemma permeability.Further more,the protective potential of La （Ⅲ） was better under low UV-B radiation than under a high one.     

Stress Sensitivity Is Associated with Differential Accumulation of Reactive Oxygen and Nitrogen Species in Maize Genotypes with Contrasting Levels of Drought Tolerance

Drought stress decreases crop growth, yield, and can further exacerbate pre-harvest aflatoxin contamination. Tolerance and adaptation to drought stress is an important trait of agricultural crops like maize. However, maize genotypes with contrasting drought tolerances have been shown to possess both common and genotype-specific adaptations to cope with drought stress. In this research, the physiological and metabolic response patterns in the leaves of maize seedlings subjected to drought stress were investigated using six maize genotypes including: A638, B73, Grace-E5, Lo964, Lo1016, and Va35. During drought treatments, drought-sensitive maize seedlings displayed more severe symptoms such as chlorosis and wilting, exhibited significant decreases in photosynthetic parameters, and accumulated significantly more reactive oxygen species (ROS) and reactive nitrogen species (RNS) than tolerant genotypes. Sensitive genotypes also showed rapid increases in enzyme activities involved in ROS and RNS metabolism. However, the measured antioxidant enzyme activities were higher in the tolerant genotypes than in the sensitive genotypes in which increased rapidly following drought stress. The results suggest that drought stress causes differential responses to oxidative and nitrosative stress in maize genotypes with tolerant genotypes with slower reaction and less ROS and RNS production than sensitive ones. These differential patterns may be utilized as potential biological markers for use in marker assisted breeding.