牡丹切花保鲜研究进展

牡丹是我国的传统名花之一,牡丹切花在国际市场有一定的需求。笔者对有关牡丹切花保鲜研究概况和研究方法进行了系统的论述,并对牡丹切花保鲜研究中存在的问题和研究重点进行了展望。     

高效低风险是农药发展的必由之路

农药是与人类生存活动紧密相关的一类重要的农用化学品,随着人们对环境安全和自身健康日益关注,对农药认识和理解趋于全面和理性.笔者认为,目前对农药发展的要求已由“高效、低毒、低残留”发展和延伸到高效低风险的阶段.农药产业也应调整思路,积极更新产品.高效低风险农药已成为当前农药发展的必由之路.     

三种杜鹃花组培快速繁殖初步研究

用三种杜鹃花的茎尖组培快速繁殖,主要对增殖培养中激素种类与浓度进行了较深入的研究。根据本试验的增殖系数和培养时间推算,一个茎尖一年内可获得试管苗15000～20000株。     

新农村建设中农村生态环境保护对策研究

农村生态环境保护是建设社会主义新农村的重要内容,但是目前我国农村生态环境问题日益严重。主要分析了农村生态环境面临的主要问题,并提出了一些解决之道。     

排酸处理对湘南黄牛氨基酸以及脂肪酸的影响

[目的]为改善湘南黄牛肉用品质,并在生产中推广应用。[方法]试验选取6头同一品种、月龄接近的湘南黄牛经同一饲喂条件育肥后进行屠宰,测定排酸前后牛肉中氨基酸、脂肪酸含量等指标。[结果]结果表明,排酸牛肉组氨酸、甘氨酸、蛋氨酸、肌氨酸、色氨酸、∑鲜味氨基酸、∑苦味氨基酸含量显著升高(P0.05);丙氨酸、缬氨酸、脯氨酸、苏氨酸、瓜氨酸、∑甜味氨基酸含量显著降低(P0.05)。排酸牛肉十二酸、十四酸、十五酸、顺-11-二十碳烯酸、饱和脂肪酸(SFA)含量显著升高(P0.05);顺-9,12,15-十八碳三烯酸、顺-8,11,14-二十碳三烯酸、顺-5,8,11,14-二十碳四烯酸、二十碳五烯酸、二十二碳六烯酸、多不饱和脂肪酸(PUFA)、PUFA/SFA、n-6 PUFA、n-3 PUFA含量显著降低(P0.05)。[结论]最终得出,通过排酸处理湘南黄牛能够满足人体从肉类摄取氨基酸的需求,同时有效改变脂肪酸含量,提高肉用品质。     

Extracts of killedPenicillium chrysogenum Induce resistance against Fusarium wilt of melon

Dry fungal biomass ofPenicillium chrysogenum (dry mycelium), a waste product of the pharmaceutical industry, was extracted with water and applied to the roots of melon plants before or after inoculation withFusarium oxysporum f.sp.melonis (Font). Seedlings (4–6 days after emergence) treated with either acidic dry mycelium extract (DME) or neutralized dry mycelium extract (NDME) were protected against challenge infection withFom. A single drench with 2–5% DME applied 12–72 h before inoculation provided significant control of the disease compared with water-drenched, challenged seedlings. No protection was seen in plants treated 0–6 h before inoculation or 0–48 h after inoculation. Neither DME nor NDME (0.5–5%) had any effect on fungal growthin vitro, which implied that disease controlin vivo was mediated by induced resistance. The resistance induced by DME protected melon plants not only against race 1,2, but also against the three other races of the pathogen, indicating a race-non-specific resistance againstFom. Both DME and NDME significantly increased peroxidase activity and free L-proline content in seedlings 12 h and 48 h after soil drench, respectively. Resistance to Fusarium wilt was significantly associated with elevated levels of peroxidase activity but not with free L-proline content. Thus, peroxidase might be involved in the defense mechanisms activated by DME or NDME. http://www.phytoparasitica.org posting Aug. 31, 2001.     

近５０年辽西北半干旱区降水变化与 花生水分适宜性评价

辽宁省花生优势区域的拓展及转移受多种因素制约,且以降水量的制约最为明显。为探讨辽宁花生产业的区域布局及拓展空间,以阜新近50 a的降水变化为例,采用降水保证率、降水变率、土壤水分蒸发量及土壤水分盈亏特征等参数分析辽西北降水规律,并进行花生水分适宜性评价。分析表明,“十年九旱”仍是辽西北基本气候特征,且这种特征可能有继续恶化趋势。该区域4-5月的降水保证率偏低,土壤缺水量达100 mm ,冬春季的降水变率大于110％,发生春旱的机率最大,对花生春播极其不利。而从花生生长季节水分分析,辽西北的降水条件基本能够满足花生生长对水分的需求,且花生生物产量 y与降水量x间显著服从于方程y＝ a＋ bx ,相关系数 r＝0．999。从区域可持续发展角度出发,辽西北花生生产需着重攻克避旱播种、生态防风蚀和避免与粮争地等三个方面的技术难点。     

基于面向对象的GF-1遥感影像采煤沉陷区湿地分类

为掌握采煤沉陷区湿地的类别和分布,促进矿区土地的复垦、规划和管理,该文以兖州煤田为例,探讨了基于GF-1遥感影像的面向对象的采煤沉陷区湿地分类方法。对河流湿地和景观湿地的影像进行基于矢量的棋盘分割,采用标准最邻近法进行分类。水产养殖湿地、植被型湿地、未复垦的常年积水湿地和未复垦的季节积水湿地的影像采用基于矢量的多尺度分割,通过反复试验获取最优分割参数,进而进行综合分析得到局部最优分割参数,由此确定分类层次,选取易于区分各类型湿地的影像特征建立分类规则,采用模糊分类法进行分类。选取141个样本点进行实地验证,结果表明分类精度达到96.95%,Kappa系数为0.958 4。该研究为采煤沉陷区湿地的分类提供了借鉴。     

The effects of sperm–egg ratios on polyspermy in the blood clam,Tegillarca granosa

Polyspermy in Tegillarca granosa, which leads to failure or abnormal development of early embryos, appears to be directly related to varying sperm–egg ratios. We investigated the correlation between sperm–egg ratios and conditions of embryonic development by setting six strict sperm–egg ratios and subsequently scoring fertilization rate, abnormal rate, rates of trochophore and D‐shaped larvae. When sperm–egg ratios rose from 2 × 10²:1 to 1 × 10³:1, D‐shaped larvae rate dropped significantly from 78.8 ± 13.3% to 47.8 ± 14.9% (analysis of variance, P< 0.05), and to 3.6 ± 2.8% in the 2 × 10⁴:1 group. Using fluorescence microscope observation, polyspermy rates rose from 2.6 ± 0.8% to 72.9 ± 4.8% with increases in sperm–egg ratios. Sperm–egg ratios were therefore correlated with polyspermy rate, which seriously affected larval survival. Under the premise of higher fertilization rate, the sperm–egg ratios of ≤2 × 10²:1 appeared to be more beneficial for embryonic development of T. granosa.     

反刍动物瘤胃内甲烷的产生及营养调控

概述了反刍动物甲烷排放研究的意义、瘤胃内甲烷的产生机制和影响因素、及从营养控制方面减少甲烷排放量的几种方法。