外源乙醛对中熟和晚熟桃果实采后活性氧代谢的影响

 【目的】研究外源乙醛处理对桃果实采后活性氧代谢的影响。【方法】以中熟品种‘久保’和晚熟品种‘绿化9号’桃为试材,用0、0.25、0.50 和 1.00 ml?L-1 乙醛处理果实 12 h ,研究桃果实在（20±1）℃与(0±1)℃贮藏期间活性氧代谢的变化。【结果】在2种贮藏温度下,1.00 ml?L-1乙醛处理提高了桃果实超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）的活性,降低了超氧负离子游离基（ ）生成速率和过氧化氢（H2O2）含量;0.50 ml?L-1处理在室温下降低了 生成速率和H2O2含量,提高了SOD和POD的活性,但对CAT活性的影响不显著,在0℃下,0.50 ml?L-1处理效果不明显;0.25 ml?L-1处理在2种贮藏温度下效果均不明显。在货架期间,不同处理间这些变化的差异不明显。【结论】在2种贮藏温度下,适当浓度的外源乙醛处理可有效延缓桃果实活性氧代谢。     

基于AOS的扩展C-V模型及背景填充耦合的单板节子缺陷识别

分析木材单板节子缺陷图像的特点,提出一种基于AOS的扩展C-V模型及背景填充耦合的单板节子缺陷识别算法。首先,对Chan-Vese提出的基于Mumford-Shah模型的水平集图像分割算法进行改进,使分割速度得到提高;其次,用AOS算法改进原模型的差分格式,使得差分格式无条件稳定;最后,结合背景填充技术,使得到的新图像缩减了目标与背景间的特征差别。通过对比试验,表明该分割方法能够快速识别单板单个节子缺陷,充分说明该耦合方法比Chan-Vese方法及其改进方法有更好的分割效果。通过用多水平集作为初始轮廓演化曲线,结果表明该方法也可快速实现对单板多节子缺陷图像的识别,实现对单板节子图像的多目标分割。     

Effect of Juglone on Active Oxygen Species and Antioxidant Enzymes in Susceptible and Partially Resistant Banana Cultivars to Black Leaf Streak Disease

The black leaf streak disease (BLSD), caused by Mycosphaerella fijiensis, is the most destructive disease of bananas and plantains around the world. Breeding for resistance is the most promising strategy to fight this disease especially in small farmer plantations. Mycosphaerella fijiensis produces many phytotoxins such as juglone, which can be used, jointly with field and inoculations under controlled conditions, for screening banana cultivars for BLSD-resistance. This non-host specific phytotoxin has been shown to act on chloroplasts and disturbs the proton electrochemical gradient across the plasmalemma membrane. Moreover, an involvement of the oxidative burst during the interaction has been suggested. The present study was carried out using two cultivars that differed for either their juglone-responses or their resistance to BLSD (cv. Grande Naine susceptible to BLSD and juglone and cv. Fougamou partially resistant to BLSD and highly tolerant to juglone). The production of active oxygen species (AOS) and the enhancement of the enzymatic and/or non-enzymatic AOS-scavenging systems were investigated after treatment of the two cultivars with juglone. The time-course of AOS-production and AOS-scavenging was shown to be the key difference between these two tested cultivars after treatment with juglone. Thus, an early release of AOS (O₂⁻ radical and H₂O₂) and a quick stimulation of a preferment anti-oxidant system (superoxide dismutases, catalases, and peroxidases) was observed for cv. Fougamou as compared to cv. Grande Naine for which a late and weak generation of AOS accompanied by a late stimulation of the anti-oxidant systems were detected.     

From Web Resources to Agricultural Ontology: a Method for Semi-Automatic Construction

In recent years,with the rapid development of information science,ontology becomes a popular research topic in the fields of knowledge engineering and information management.The reason for ontology bei...     

陆地棉体细胞胚发育过程中AOS基因家族的表达谱初步分析及功能预测

茉莉酸在调控棉花体细胞胚增殖方面有重要作用,而丙二烯氧化物合酶(AOS)是植物茉莉酸合成途径中的关键酶。作者鉴定出在胚发育过程中表达的AOS基因,这些基因编码区长度均在1500 bp左右,被定位在5条染色体上,有2个基因含有内含子。对其启动子元件分析发现,它们可能受激素和胁迫的调控在体细胞胚胎发生中起作用。荧光定量分析发现,这些基因在棉花不同组织中的表达模式主要分为3类,GhAOS1和GhAOS6在棉花胚发育过程中表达量相对较高,GhAOS2和GhAOS3在棉花愈伤和胚性愈伤中表达量相对较高,GhAOS4和GhAOS5在茎和叶中表达水平相对较高,暗示这些基因的表达有时空特异性,且GhAOS1和GhAOS6可能在棉花胚发育中发挥重要作用。亚细胞定位分析显示,大部分被定位在过氧化物酶体中,可能参与调控光呼吸、体细胞胚成熟和萌发。上述分析为进一步研究AOS基因家族在棉花体细胞胚发育中的功能奠定了基础。     

基于Visual C++的AOS卫星中转节点仿真系统设计

AOS通信系统在空间领域已占据重要地位,相应的仿真技术也得到了迅速的发展,本仿真系统选用多点通信系统中的一个卫星中转节点作为研究对象,借助Visual C++平台,根据AOS协议标准,对卫星中转节点的各模块进行了设计和仿真实现。     

自身他感作用物对木麻黄苗木活性氧代谢影响

以15年实生木麻黄根系水浸液作为他感作用物,采用水培方法研究木麻黄自身他感作用物对木麻黄苗木活性氧代谢的影响。结果表明,在木麻黄自身他感作用下,木麻黄苗木叶片活性氧代谢失衡,活性氧大量积累。具体表现在:细胞膜透性增强,膜的结构和功能受到破坏,电解质增强,内溶物外渗增加;丙二醛(MDA)含量增加,膜质过氧化程度加剧;叶细胞中超氧阴离子自由基O-2产生的速率和H2O2含量增加,活性氧产生和清除平衡被打破,细胞内活性氧大量累积;活性氧酶促消除系统失衡,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱苷肽还原酶(GR)和过氧化物酶(POD)活性下降,细胞清除O-2和H2O2的能力减弱。     

Boron uptake and toxicity in maize genotypes in relation to boron and phosphorus supply

The effect of increasing levels of applied phosphorus (P) and boron (B) on the growth and the concentration and uptake of P and B were examined in eight maize genotypes (Furio, Riogrande, Sele, DK 743, Helix, Missouri, Betor, and Poker) with two individual greenhouse experiments. Phosphorus was applied at 0, 50, and 100 mg kg^‐1 in Experiment I and B at 0, 10, and 30 mg kg^‐1 levels in Experiment II. Application of B resulted in increased concentration and uptake of B and a decreased P concentration and uptake in all genotypes. The dry weight of all genotypes was decreased by application of B. However, applied P decreased B concentration and uptake and increased P concentration and uptake of the genotypes. The dry weight of all genotypes was increased by application of P. These experiments show that B is more toxic in the absence of rather than the presence of P, and that this toxicity could be alleviated with applications of P in the calcareous soils of semiarid areas.     

赤霉菌粗毒素对小麦幼苗活性氧代谢的影响

比较赤霉菌粗毒素液或外源SA预处理抗病和感病小麦幼苗不同时间,叶片活性氧代谢变化。结果表明：赤霉菌粗毒素液处理小麦幼苗根部2—48h后．O2^-产率先增加后降低,感病品种（川麦28）H2O2含量逐渐增加;用外源SA预处理小麦幼苗叶片2h后再用赤霉菌粗毒素液处理小麦幼苗根部2—48h,抗、感病品种的O2^-产率和H2O2含量均明显提高,且抗病品种（89107）先于感病品种达到其峰值,粗毒素液处理24h后抗性品种保护酶（SOD,CAT和POD）活性比感病品种的高。抗病品种PAL活性变化对SA预处理响应强烈。SA可能作为信号分子之一,诱发小麦幼苗对赤霉菌粗毒素液产生一定的系统抗性。     

草酸对冷藏期间桃果实抗氧化系统和PPO活性的影响

 桃( Prunus persica L. ) 栽培品种‘八月脆’果实采后经5 mmol·L ^{- 1}草酸溶液浸泡10 min后在低温条件下贮藏, 与对照相比, 果实的CAT和PPO活性提高, SOD和POD活性在贮藏10 d后较高; 还原型抗坏血酸(AsA) 含量下降减缓; 超氧阴离子(O₂· ) 生成速率随贮藏增加, 过氧化氢(H₂O₂ ) 含量先升后降, 但经草酸处理后O₂ ·生成速率和H₂O₂ 含量分别在5 d和5、10 d时显著低于对照。说明草酸处理通过提高果实抗氧化防御系统的能力和PPO活性来延缓果实成熟和增强果实抗病能力。