几种叶菜叶片硝酸盐含量差异及原因的研究

采用相同营养液进行水培的方式研究了7种叶菜硝酸盐含量积累及其原因。结果表明,7种叶菜叶片硝酸盐含量差异较大,这种差异主要是由于不同叶菜叶片内硝酸还原酶活性的差异、根系对硝酸盐的吸收速率以及叶片中硝酸盐的代谢库和贮存库的不同造成的;不同叶菜叶片硝酸盐含量与内在硝酸还原酶活性和代谢库的大小有明显的负相关,与贮存库和吸收速率有明显的正相关。     

Efficiency of manganese and copper uptake by excised roots of maize genotypes

In this study three maize (Zea mays L.) genotypes, a single‐cross hybrid and its parents were evaluated for their efficiency to absorb Mn²⁺ and Cu²⁺. All experiments were run using excised roots and uptake efficiency was expressed as Vmax and Km. Also, the genotypes were investigated for possible mutual effects between Mn²⁺ and Cu²⁺ during their absorption by roots.

Vmax values for both Mn²⁺ and Cu²⁺ showed that an appreciable heterotic effect occurred, higher for Mn²⁺ than for Cu²⁺ At the same time the hybrid displayed with respect to the inbreds higher Km values for Mn²⁺ and only slightly lower Km values for Cu²⁺. Hence a clear positive level of heterosis was evidenced with reference to the maximum absorption capacity

(Vmax) but not to the affinity (1/Km) for substrates. Cu²⁺ inhibited uptake of Mn²⁺ in a non‐competitive fashion (Vmax for Mn²⁺ fell in the presence of Cu²⁺ while Km remained constant) and this effect appeared to a lesser extent in the hybrid than in its parentals. At the same time no relevant effects of Mn²⁺ on the uptake of Cu²⁺ could be evidenced.     

板栗叶片POD动力学研究

研究板栗叶片的POD动力学特性,结果表明,板栗叶片POD的最适温度为38℃,最适pH为4.6,最适H2O2浓度为0.1%,Km值为128.17mmol/L,Vmax值为281.68U/(s·gFW).硫脲和亚硫酸氢钠对POD活性具有一定的抑制作用,而氯化钙和硝酸钾对POD活性具有一定的激活作用.     

抗旱品种‘豫烟6号’钾吸收积累特性研究

为研究抗旱烟草品种苗期的钾吸收积累特性,采用砂培和水培的方法,以‘豫烟6号’、‘农大202’和常规品种‘K326’3个基因型烟草作为材料,研究‘豫烟6号’的根系生理特性和钾吸收特征,以及干物质积累差异。结果表明,在不同供钾条件下,‘豫烟6号’的干物质积累以及各器官钾含量均与‘农大202’相近,而显著高于‘K326’,并且具有较大的吸收面积和较强的根系活力。钾吸收动力学的研究结果表明,‘豫烟6号’的最大吸收效率(Vmax)接近‘农大202’,而极显著的高于‘K326’,而不同基因型烟草间米氏常数(Km)和最低浓度(Cmin)无明显差异。结果表明,‘豫烟6号’具有较强的钾素吸收和积累能力,是一个富钾的烟草品种。     

几种叶菜叶片硝酸盐含量差异及原因的探究

采用相同营养液进行水培的方法研究了7种叶菜硝酸盐含积累,并分析其原因。结果表明:不同叶菜叶片硝酸盐含量差异较大,原因是叶片内在硝酸还原酶活性的差异、根系对硝酸盐的吸收速率以及硝酸盐的代谢库和贮存库的不同造成的;叶片硝酸盐含量与内在硝酸还原酶活性和代谢库的大小有明显的负相关,与贮存库和吸收速率有明显的正相关。     

婆婆纳、离子草与小花糖芥三种麦田杂草吸收NO_3~-,H_2PO_4~-,K~+的动力学研究

采用耗竭法,研究了婆婆纳、离子草与小花糖芥三种麦田常见杂草吸收NO3-、H2PO4-、K+的动力学差异。试验结果表明:在吸收NO3-、H2PO4-、K+时,婆婆纳的Vm ax值要显著高于其它两种杂草;在吸收H2PO4-时,离子草的Km值要显著低于其它两种杂草;而在吸收K+时,却是小花糖芥的Km值最低。从而说明:三种杂草中,婆婆纳最能适应高N、P、K养分条件,离子草最能适应低P养分条件,而小花糖芥则最能适应低K养分条件。     

Nitrate and Ammonium Uptake Kinetics of Three Annual Range Species

The uptake kinetics of nitrate and ammonium ions was compared for the annual range species: subclover ( Trifolium subterraneum L.), soft chess ( Bromus mollis L.), and broadleaved filaree ( Erodium botrys [Cav.] Bertol.) to study competitive interactions in nitrogen deficient soils. Fifteen-day-old seedlings were allowed to deplete solutions of nitrate or ammonium in the range of 5 to 500 μM concentrations for a 10-hour period during which net uptake (depletion) was monitored by a sensitive conductance technique. Subclover uptake rates were markedly less than those for soft chess and filaree for both nitrate and ammonium at both low and high concentrations. The evidence supports the hypothesis that subclover is a poor competitor for soil N in part because of this physiological difference.