氨氮和亚硝酸氮对偏顶蛤的急性毒性研究

[目的]研究氨氮和亚硝酸氮对偏顶蛤的急性毒性,为合理调控偏顶蛤水体中氨氮与亚硝酸氮提供参考价值。[方法]采用常规生物毒性试验方法,研究偏顶蛤对氨氮和亚硝酸氮毒性的耐受力。[结果]氨氮对偏顶蛤的半致死浓度96 h LC50为158.85 mg/L,安全浓度(SC)为15.89 mg/L;非离子氨对偏顶蛤半致死浓度96 h LC50为14.06 mg/L,安全浓度(SC)为1.41 mg/L。亚硝酸氮对试验蛤的半致死浓度96 h LC50为54.20 mg/L,安全浓度(SC)为5.42 mg/L。[结论]与亚硝酸盐相比,偏顶蛤对总氨氮毒性的耐受力更强,非离子氨对偏顶蛤的毒性最强。     

缺锌条件下小麦的养分吸收状况及不同基因型的耐性差异

采用螯合-缓冲营养液（Chelator-buffer culture solution）进行培养试验,对缺锌条件下3种小麦基因型（绵阳19、邯6172、新麦13）的生长发育状况及对P、Cu、Fe、Mn营养的影响进行了研究,并且应用4种指标,即锌效率（缺锌与锌充足供应条件下小麦地上部干物质之比）、相对冠根比（缺锌与锌充足供应条件下小麦冠根比之比）、缺锌条件下小麦地上部的锌吸收量、干物质量,对3种小麦的耐缺锌能力进行了比较。结果表明,在锌缺乏条件下小麦地上部生长量明显降低,而根系依然能保持相对较强的生长发育能力;不同小麦基因型对缺锌的耐性存在明显差异,其中邯6172的耐性最强;在缺锌胁迫条件下,小麦地上部Cu、Fe、Mn含量及Cu／Zn、Fe／Zn、Mn／Zn均明显升高,地上部锌含量与Cu、Fe、Mn含量均呈极显著负相关,说明锌缺乏能够促进Cu、Fe、Mn在地上部的累积。与此相反,锌缺乏条件下小麦P含量及吸收量均明显降低,地上部磷、锌含量之间极显著正相关,但与Cu,Fe,Mn相似,缺锌后P从根系向地上部的转运率升高。同时,对缺锌耐性最强的小麦基因型邯6172在锌缺乏条件下,地上部Cu、Fe、Mn含量的升高与P含量的降低幅度均是3种供试小麦中最大的,似乎表明小麦对锌缺乏的耐性大小与对Cu、Fe、Mn的吸收能力及与对P吸收的抑制有关。     

铁春1号"小麦耐白粉病机制研究

 铁春1号小麦耐小麦白粉病的机制是:①光合补偿作用:"铁春1号"小麦旗叶的表现光合速率下降较小,而真正光合速率比健康植株高,表明侵染点间的绿色组织具有光合补偿作用,一定程度上弥补病原菌的破坏与消耗。②超氧化物歧化酶活性增强,能及时清除因病害胁迫产生的超氧自由基(O₂·),避免了O₂对细胞膜的伤害。"铁春1号"膜磷脂种类在染病后没有变化,而感病品种膜磷脂在染病后增加了2个组份。③贮存物质运转的补偿作用:"铁春1号"在病害胁迫下,叶、茎、叶鞘中的干物质,以及氮、磷等养分的运出率增大,通过充分利用贮存物质部分的补偿光合产物低之不足。最终使籽粒中氮、磷及碳水化合物不减少。     

苜蓿品种间种子萌发及苗期耐盐性差异的研究

本文模拟内蒙古河套灌区盐分组成,对九种紫花苜蓿品种种子萌发及苗期的耐盐性进行了研究。结果表明:苜蓿品种在种子萌发期和苗期所能忍受的极限盐浓度不同,分别为1.0%和0.7%左右,揭示出苗期对盐分反应较种子萌发期更为敏感。综合评定苜蓿品种耐盐能力强弱:芋县苜蓿=准格尔苜蓿≥沙湾苜蓿>新疆抗旱苜蓿=苏联36号苜蓿=公农1号苜蓿≥阳高苜蓿>公农2号苜蓿=紫苜蓿。     

Difference In Tolerance To Potassium Deficiency Between Two Maize Inbred Lines

Abstract

Northeast China Produces An Abundance of Maize (Zea Mays L.), and Improvement of Maize Yield At This Region Correlates Closely With Ensure Food Supply Safely of China. in Recent Years, Deficiency Or Relative Deficiency of Potassium (K) in The Soil Is An Important Limitation To Maize Production. Maize inbred Lines Tolerant To K Deficiency (T) and Sensitive To K Deficiency (C) Were Hydroponically Grown in 1/2 Hoagland Solution To Study The Possible Mechanism of Maize Tolerance To Potassium Deficiency From Physiological Point of View. With The Reduction of K⁺ Concentration, Dw of The Plant Became Apparently Greater in T Than in C, The Symptom of Potassium Deficiency Advanced in C. Under K Deficiency, The Taproot Elongation increased and Root Top Ratio Decreased To A Greater Degree in C Than in T, C Had Fawer Lateral Roots. T Had A Stronger K⁺-Uptake Ability Than C, and The Difference Was More Obvious in Culture Solution With A Lower K⁺ Concentrations of Culture Solution. K⁺ Dependent H⁺ Extrusion From The Root Treated With K⁺ Deficiency Was Larger in T Than in C.     

湘烟5号对植烟土壤镉耐受力响应研究

为探讨烟草对镉（Cd）胁迫的耐受性,以湘烟5号为材料进行盆栽试验,研究了不同浓度硫酸镉一次性灌溉施入对烤烟生长发育特性的影响。结果表明,同时期内,随着有效态Cd浓度的提高,烟株主要农艺性状指标以及根茎叶各部位干物质积累量呈下降趋势;烟叶叶绿素相对含量（SPAD）呈下降趋势,过氧化氢酶（CAT）、过氧化物酶（POD）和超氧化物歧化酶（SOD）活性显著下降,丙二醛（MDA）和脯氨酸含量显著增加,可溶性糖含量先升高后下降。当有效态Cd浓度超过6.0mg/kg时,可能是因为细胞膜系统受到严重损害而导致烟株生长发育严重受损,因此本研究条件下湘烟5号对有效态Cd最大耐受浓度为6.0mg/kg。此结果为烤烟植烟区选择及烤烟安全优质生产提供了参考。     

露地黄瓜新品种北京403的选育

北京403是一个高产、抗病的露地黄瓜一代杂种。其母本为自交系96-Ch4,父本为96-55。该品种较耐热,抗霜霉病、白粉病和CMV等病害|植株生长势强,以主蔓结瓜为主,第5～7节着生第1雌花,其后每隔2～3节出现1个雌花。瓜色深绿、有光泽,长约33 cm,单瓜质量200～250 g,中刺瘤,白密刺,质脆味甜|每667 m2产量4 000～5 200 kg。目前已在北京、河北、辽宁、陕西、山西等地推广。适于北方和南方部分地区春季露地栽培。     

不同品种杞柳对高锌胁迫的忍耐与积累研究

采用营养液培养实验方法,研究了高浓度Zn对3个杞柳品种"微山湖","大红头"、"一枝笔"生长,耐性及Zn吸收积累的影响.结果表明,Zn对杞柳生长的影响与品种、植物部位以及介质中Zn浓度有关,低Zn(100 μmol·L-1)、高Zn(1 000 μmol·L-1)均不同程度降低了3个杞柳品种的生长参数,低Zn显著减少了"微山湖"、"大红头"的根长及"大红头"根生物量,高Zn显著降低了3个品种株高、根长、生物量等生长参数;3个品种对Zn吸收与积累存在一定差异,地上部Zn含量随介质中Zn浓度升高而降低,根系中Zn含量随Zn浓度升高而增加,Zn在根中含量高于地上部,低Zn时3个品种地上部Zn含量为1477.58～1 583.19 μg·g-1,平均1 530.29 μg·g-1;位移系数(TF)随Zn浓度升高而降低,低Zn时"微山湖"、"一枝笔"位移系数高于"大红头"而接近1;迁移总量随Zn处理浓度增加而降低,3个品种迁移总量为2 332.58～3 871.41 μg,平均3 266.27μg,迁移总量比大于1;耐性指数(TI)随营养液中Zn浓度增加而降低,低Zn时3个品种耐性指数均大于0.5.以上结果表明,高Zn严重干扰了3个杞柳品种的生长,3个品种对低Zn有较强的耐性及积累能力,显示出具有修复≤100 μmol·L-1Zn潜力.     

Screening Cultivars at Low Dissolved Oxygen Level for Water-seeded Rice

Abstract

Eighteen local varieties of japonica rice and two japonica rice varieties introduced from Japan were studied to collect the basic information on the relationship between the amylographic characteristics and eating quality. The materials were planted in the first and second crop seasons of 1998 in central Taiwan. The pasting behaviors including peak viscosity, hot-paste viscosity, cool-paste viscosity, breakdown viscosity, setback viscosity, consistency viscosity, pasting temperature and the time to reach peak viscosity were measured. The eating quality of rice was evaluated by trained panelists in terms of overall palatability score. All amylographic characteristics except for hot-paste viscosity and overall palatability score varied significantly between the first and the second crops and the interactions between crops and varieties were also significant for all characteristics. Teikeng 2, Teikeng 3, Teikeng 4, and Teikeng 9 showed higher overall palatability scores than the other varieties in the first crop, and Koshihikari and Teikeng 6 showed the best overall palatability in the second crop, respectively. The coefficient of variation was higher in the second crop than in the first crop except the time to reach peak viscosity. Setback viscosity showed the highest variation in all amylographic characteristics. The heritability estimate was also higher in the second crop than in the first crop with the exception of consistency viscosity. The highest heritability values were given for consistency and breakdown viscositites in the first and second crops, respectively. However, the lowest heritability value was given for the time to reach peak viscosity in both crop seasons. The close relationship among peak, hot paste, and cool paste viscosities was found for both crops. The highest correlation coefficient was found between peak and breakdown viscosities in both crops. A significant negative correlation between breakdown viscosity and setback viscosity was observed in both crop seasons. Likewise, peak viscosity had a significant correlation with setback viscosity in both crops. In the first crop, the palatability score was negatively correlated with pasting temperature (r=-0.43**) but positively correlated with the time to reach peak viscosity (r=0.36*). There was a positive correlation between palatability score and peak viscosity (r=0.33**) and a negative correlation between palatability score and setback viscosity (r=0.34**) in the second crop.