甘蓝田蜘蛛群落结构及优势种群动态分析

采用物种丰富度(S)、每单位样方个体数(N)、多样性指数(H′)、优势度指数(E) 和均匀度指数(D), 对不同时期甘蓝田蜘蛛群落结构及其优势种群动态进行了初步研究。结果表明, 甘蓝田蜘蛛种类有8科, 18属, 23种, 其中优势种为星豹蛛、阴瘤胸蛛、草间小黑蛛、黑侏儒蛛、和温室希蛛; 随着甘蓝的生长发育, 蜘蛛群落的多样性值逐渐增大, 群落逐渐趋于稳定, 优势种的种群密度也随之上下波动。这对揭示蜘蛛在菜田生态系统中控制害虫的发生发展机理及对保护和利用这类天敌资源有重要的意义。     

不同肥料组合对酸性土壤白菜产量和品质的影响

通过田间小区试验,研究了肥料组合对酸性土壤白菜产量和品质的影响.结果表明,与CK处理相比,不同肥料组合白菜产量提高了22.3 %～114.6 %,以N_(20)P_(10)K_(150)M+L处理产量最高, N_(20)P_(10)K_(15)M+C处理其次.与N_(20)P_(10)K_(15)处理相比,在N_(20)P_(10)K_(15)基础上减氮、磷、钾处理显著降低了白菜产量7.6 %～19.3 %,而在N20P10K15基础上增施石灰、炭灰和菜籽粕的处理,显著提高白菜产量4.18 %～41.6 %.在N_(20)P_(10)K_(15)基础上增施炭灰显著降低了白菜硝酸盐含量,提高了卫生品质.不同肥料组合(除N_(20)P_(10)K_(15)M+C处理外)均提高了白菜维生素C 含量,且以N_(20)P_(10)K_(15)L处理的增幅最大,达43.0 %.增施石灰、菜籽粕和炭灰的白菜氨基酸含量增加,以N_(20)P_(10)K_(15)M+C处理的效果最佳.单一配施石灰和炭灰的处理白菜还原糖含量增加.增施石灰、炭灰和菜籽粕的处理提高白菜氮、磷和钾肥的养分利用率分别为47.1 %～208.3 %, 53.7 %～122.0 %和3.70 %～41.8 %.     

Effects of Graded Levels of Cadmium on Spinach and Cabbage Grown in an Inceptisol

Cadmium (Cd) contamination of the soil and its concentrations in spinach and cabbage were studied in a pot culture experiment. Eight levels of Cd (0–100 mg kg^?1 soil) were applied singly. Application of Cd of up to 10 and 15 mg kg^?1 resulted in safe Cd concentrations (1.56 and 1.38 mg kg^?1) in the shoots of spinach and cabbage, respectively, at the consumable stage. The total chlorophyll content gradually decreased with the addition of Cd, and the maximum decreases were 31.7 and 32% in spinach and cabbage, respectively, at 60 days of crop growth in the treatment Cd₁₀₀ over the control. The greatest diethylene triamine penta-acetic acid (DTPA)–extractable Cd contents in the postharvest soil of spinach and cabbage were 22.09 and 24.22 mg kg^?1, respectively, in the treatment Cd₁₀₀. The DTPA Cd was significantly negatively correlated with leaf area and total chlorophyll content while positively correlated with root and shoot Cd concentrations of spinach and cabbage.     

Monitoring sap nitrate in vegetable crops: Comparison of test strips with electrode methods,and effects of time of day and leaf position

Abstract

A field crop of 3‐month old cabbages was sampled every 2 h from 0600 h until 2000 h. At each sampling, an upper, middle and lower leaf were taken from four plants, and their petiole nitrate status measured by three methods (a) “Merckoquant”; test strips (b) specific ion electrode on a fresh macerated extract and (c) the same electrode on an extract of oven dry tissue. All three methods led to similar conclusions: a. there were very big differences in concentration with leaf position, the middle leaf having the highest;

b. there were large concentration differences between plants, especially for the lower leaves;

c. the effect of time of day was not significant.

The test strips are capable of giving satisfactory results provided that sufficient plants are sampled, but values thus obtained for sap may be lower than for macerated fresh tissue, especially at the low end of the concentration range.     

啶虫脒在甘蓝中的残留测定及安全使用评价

田间小区试验结果表明:40%啶虫脒水分散粒剂在土壤中的半衰期为1.4～2.6 d,药后5 d消解90%以上;在甘蓝中的半衰期为1.1～2.2 d,药后5 d消解92%以上。最终残留量测定结果表明:40%啶虫脒在甘蓝上用于防治蚜虫、菜青虫,以22.5～33.75 g a.i./hm2,连续喷药2～3次为宜,药后7 d收获的甘蓝中啶虫脒残留量为0.022～0.382 mg/kg,均低于最高限量标准0.5 mg/kg。按照推荐使用剂量在甘蓝上使用,采收间隔期7 d是安全的。     

甘蓝密度与惠满丰最佳组合及其协同效应的研究

采用Ｄ－饱和最优回归设计田间试验测得的参数，建立了以甘蓝产量为目标函数的数学模型。通过数学运算得出，１ｈｍ２底施惠满丰高效活性肥９６０．７ｋｇ、叶喷惠满丰活性液肥３７５０ｍｌ，栽植密度６８５４４株，可望获得最高产量６４１３２ｋｇ，并对单因素效应、互作效应作了剖析。     

白菜新品种‘矮抗5 号’

 ‘矮抗5 号’系白菜一代杂种, 亲本为SW-13 和V-126 (矮×短) , 于1998 年育成。该品种株形直立、束腰, 叶片广卵圆形、绿色, 叶柄半圆、白色、质嫩, 叶片与叶柄质量比值为0.59 , 单株质量约为0.3 kg。高抗TuMV , 抗霜霉病和黑斑病, 适宜在喜食白梗菜的地区进行夏季和秋季栽培。     

水肥耦合下草炭对小白菜生长的影响

为了探讨水肥耦合作用下,不同比例的不同草炭对植物生长的影响。以小白菜为供试植物,通过4个灌水水平和施肥与不施肥两个肥分水平处理,采用了石河子草炭与加拿大草炭不同添加量处理在温室里进行盆栽试验,试验结果表明:施肥与不施肥对小白菜根系发育没有明显影响,而草炭的添加有利于其根系的发育和叶绿素的增加。在50%(对照饱和田间持水量为100%)灌水水平下,草炭对小白菜的生长反而起抑制作用,降低了其地上部鲜重,随着灌水量的增加,草炭的整体优势得以发挥,当灌水量达到100%时、125%时,草炭保水的优势发挥了,8%石河子和5%加拿大草炭混合处理的明显优于对照,地上部鲜重达到了对照4倍多。因此,8%石河子和5%加拿大草炭在100%灌水条件下是比较理想的处理方案,有利于小白菜的生长发育。     

等电聚焦同工酶电泳技术鉴定甘兰一代杂种纯度

等电聚焦丙烯酰胺凝胶电泳方法分析了京丰一号、中甘十一甘兰一代杂种及双亲幼苗的过氧化物同工酶,共分离出12条谱带,两个杂交组合F_1杂种与亲本间同工酶图谱表现出明显不同,均为互补型差异。在此基础上,我们开展了应用等电聚焦电泳技术对甘兰杂交种纯度的检测,并同时在田间进行验证性测定,酶谱纯度和田间纯度二者回归方程式为y=7.93 0.93x,相关系数r=0.96.对r进行t测验t=4.47>2.79(t_(0.01)=2.79,n=26),表明同工酶测定和田间测定结果之间存在着极显著的正相关关系。     

小白菜镉耐性形成的生理生化机理研究

以50μmol/L Cd胁迫培养13个品种的小白菜,通过形态指标和生理生化指标的测定,探讨其Cd耐性形成的生理生化应答机制。结果表明:Cd胁迫下,供试材料生长和生理生化代谢均不同程度受到抑制,但与其茎叶Cd累积量无直接关系,且不同品种小白菜对Cd耐性不同。对供试材料Cd耐性指数(Tolerance index,TI)分析表明,基于植株干物质累积的耐性指数(TI-P)与基于茎叶生长的耐性指数(TI-S)极显著相关(R2=0.686),而前者与基于根系生长的耐性指数(TI-R)的显著相关(R2=0.349)。可见,以基于茎叶生长的耐性指数比基于根系生长的更能反映小白菜的Cd耐性。Cd胁迫条件下,供试材料体内脯氨酸(Pro)、丙二醛(MDA)含量以及抗坏血酸过氧化物酶(AsA-POD)和超氧化物歧化酶(SOD)活性都有不同程度的提高。Cd胁迫下,各品种叶片脯氨酸增量、SOD活性增量均与供试小白菜Cd耐性正相关,二者可作为供试材料Cd耐性的生化指标。