辣椒苗期耐低氮指标与评价方法研究

以25份不同基因型辣椒为材料,采用苗期营养液水培的方法,对辣椒苗期耐低氮筛选指标与评价方法进行了研究。结果表明,低氮处理对辣椒18个苗期形态和生理指标均有影响,但影响的程度存在基因型差异。叶面积、地上部干质量、根干质量、根冠比、植株干质量、地上部氮积累量、根氮积累量和植株氮积累量等8个指标的相对值变异系数最大,可作为耐低氮能力的关键评价指标。分别以筛选出的8个关键指标和18个指标标准化的变异系数为权重进行辣椒耐低氮能力模糊隶属函数综合评价,并与利用主成分分析法评价的结果进行比较。结果表明,两种评价方法结果基本一致,8个关键指标评价结果与18个指标评价结果也基本一致,耐低氮能力强和弱的前5份材料重合率达80%以上。对筛选出的3份苗期耐低氮水平不同的辣椒材料进行了成熟期耐低氮初步评价,结果成熟期耐低氮水平与苗期耐低氮水平趋于一致;苗期8个关键指标中,除根冠比外,其余7个指标均与成熟期耐低氮性显著相关。因此,利用8个关键指标和模糊隶属函数综合分析法可有效地在苗期对辣椒耐低氮水平进行大批量初步鉴定。

Studies of Indexes and Evaluation of Low Nitrogen Tolerance of Pepper at Seedling Stage

To develop a rapid and effective method for screening low nitrogen resistant pepper cultivars at seedling stage，the tolerance of 25 different pepper genotypes under low nitrogen stress was evaluated by hydroponic investigations. It indicated that 18 morphological and physiological indexes of pepper at seedling stage were affected by low nitrogen treatment，however，the effect degrees among genotypes were significantly different. Based on their higher coefficients of variation，relative values of 8 indexes including leaf area，dry weight of shoot，dry weight of root，root-shoot ratio of dry weight，dry weight of plant，nitrogen accumulation of shoot，nitrogen accumulation of root and nitrogen accumulation of plant were selected as the key indexes for screening and evaluation of low nitrogen tolerance of pepper. The low nitrogen tolerance of pepper was evaluated by fuzzy membership function with the normalized coefficients of variation of the 8 key indexes and all of the 18 indexes as weight，and the evaluation results were compared with the results of principal component analysis. It was showed that the evaluation results of the two analysis method were largely identical，so were the 8 key indexes and the 18 indexes，the coincidences rates of low nitrogen tolerance and sensitivity of the first 5 materials were above 80%. The nitrogen tolerance of 3 pepper materials with different degree of nitrogen tolerance at seedling stage was evaluated at maturity stage and it was revealed that the results were largely identical to that of seedling stage. Excepted for root-shoot ration of dry weight，significant correlations between the other 7 of the 8 key screening indexes and the nitrogen tolerance of pepper at maturity stage were observed. It is suggested that we can effectively and in large quantities evaluated the nitrogen tolerance of pepper at seedling stage by the 8 key screening indexes and fuzzy membership function.