白枪杆幼苗叶片形态和生理性状对钙的响应

  目的  研究不同钙浓度对白枪杆Fraxinus malacophylla幼苗的叶片形态指标、叶绿素质量分数及酶活性的影响，了解白枪杆幼苗在不同钙浓度下的生长发育情况，以进一步探究白枪杆对不同钙浓度的环境适应性。  方法  以1年生白枪杆实生苗为材料，研究0 (对照)、25、50、75 mmol·L?1钙浓度处理对白枪杆幼苗的叶片形态指标、叶绿素质量分数和酶活性的影响。  结果  不同钙浓度处理对白枪杆幼苗的叶片形态结构、叶绿素质量分数和酶活性有不同的影响。不同钙浓度处理间，白枪杆幼苗的叶片形态结构除比叶长和比叶面积随钙浓度的增加而增加外，其余相关指标均呈先上升后下降的趋势，且叶片数、叶生物量、比叶长、比叶面积、叶绿素质量分数、过氧化氢酶活性、过氧化物酶活性与对照差异显著(P＜0.05)。在钙浓度≥50 mmol·L?1时，对白枪杆幼苗无抑制作用，说明白枪杆幼苗对中、低钙浓度具喜适性；钙浓度为75 mmol·L?1时，对白枪杆幼苗生长发育有抑制作用，说明钙浓度过高会抑制白枪杆幼苗的生长。当钙浓度为50 mmol·L?1时，白枪杆幼苗叶片形态指标及叶片相关指标、叶绿素质量分数及酶活性均达到最大值，白枪杆幼苗生长发育最好。  结论  白枪杆幼苗适宜生长的钙浓度为50 mmol·L?1，钙浓度过高会抑制白枪杆幼苗的生长、叶片叶绿素质量分数和叶片酶活性。图1表2参28

Response of leaf morphological and physiological traits of Fraxinus malacophylla seedlings to calcium

  Objective  This study, with an investigation of the effects of different calcium concentrations on leaf morphological indexes, chlorophyll content and enzyme activity of Fraxinus malacophylla seedlings, is aimed to better understand the growth and development of F. malacophylla seedlings under different calcium concentrations so as to further explore the environmental adaptability of F. malacophylla seedlings when treated with different calcium concentrations.   Method  With 1-year-old F. malacophylla seedlings selected as the materials, a research was conducted of the effects of 0 (ck), 25, 50, 75 mmol·L?1 calcium treatments on their leaf morphological indexes, chlorophyll content and enzyme activity.   Result  Different calcium concentrations had different effects on leaf morphological indexes, chlorophyll content and enzyme activity of F. malacophylla seedlings. When treated with different calcium concentrations, with the increase of calcium concentration, all indexes of leaf morphology and structure of F. malacophylla seedlings increased first and then decreased, except for specific leaf length and specific leaf area which increased, whereas leaf number, leaf biomass, specific leaf length, specific leaf area, chlorophyll content, catalase activity and peroxidase activity were significantly different from those in control (P＜0.05). When the calcium concentration was more than 50 mmol·L?1, the treatment had no inhibitory effect on F. malacophylla seedlings, indicating that F. malacophylla seedlings responded favorably to medium-low calcium concentration. When the concentration of calcium was 75 mmol·L?1, it inhibited the growth and development of F. malacophylla seedlings, implying that too high a calcium concentration can inhibit the growth of F. malacophylla seedlings. When the calcium concentration was 50 mmol·L?1, the leaf morphological indexes, leaf related indexes, chlorophyll content and enzyme activity of F. malacophylla seedlings reached the maximum, and the growth and development of F. malacophylla seedlings were the best.   Conclusion  The optimal calcium concentration for the growth of F. malacophylla seedlings is 50 mmol·L?1 since too high a calcium concentration inhibits the growth, leaf chlorophyll mass fraction and leaf enzyme activity of F. malacophylla seedlings. Ch, 1 fig. 2 tab. 28 ref.]