不同溶解氧质量浓度对雷竹水培苗生长和生理生化的影响

  目的   了解溶解氧质量浓度对雷竹Phyllostachys violascens水培苗生长、生理指标及根系结构的影响，初步探究雷竹水培苗对缺氧的适应性机制。   方法   以雷竹水培苗为材料，设置0、2、4、6、8 mg·L?1不同溶解氧质量浓度进行处理，分析不同溶解氧质量浓度对雷竹水培苗生物量积累、叶面积、根系活力、抗氧化酶活性、光合色素质量分数及根系结构的影响。   结果   雷竹水培苗生物量积累、叶面积、根系活力、叶片抗氧化酶活性和光合色素质量分数均随溶解氧质量浓度的升高而显著升高(P＜0.05)。8 mg·L?1处理组中雷竹水培苗叶片超氧化物歧化酶、过氧化氢酶、过氧化物酶和抗坏血酸过氧化物酶活性达到峰值，分别为746.13×16.67 nkat·g?1、63.13×16.67 nkat·g?1·min?1、59 395.45×16.67 nkat·g?1·min?1和407.46 ×16.67 nkat·g?1·min?1。水培条件下，雷竹水培苗根系中形成溶生型通气组织，其面积占根系横截面面积的百分比随溶解氧质量浓度降低而显著升高(最高达到7.1%)，通气组织个数变化趋势则相反(P＜0.05)。   结论   水培条件下，溶解氧质量浓度越高，雷竹水培苗长势越好，且雷竹水培苗生长对氧气的需求大于8 mg·L?1。水培条件下，缺氧会诱导雷竹根中形成溶生型通气组织，但不足以使其具有高度耐水淹的能力。图5参50

Effects of different dissolved oxygen concentration on growth,physiology and biochemistry of hydroponic Phyllostachys violascens seedlings

[Objective]This study aims to investigate the effects of dissolved oxygen concentration on growth,physiological indexes and root structure of hydroponic Phyllostachys violascens seedlings,and to explore the adaptive mechanism of hydroponic P.violascens seedlings to hypoxia.[Method]The hydroponic P.violascens seedlings were used as materials,and the effects of different dissolved oxygen concentrations(0,2,4,6,8 mg·L^-1)on biomass accumulation,leaf area,root activity,antioxidant enzyme activity,photosynthetic pigment content and root structure were analyzed.[Result]The biomass accumulation,leaf area,root activity,leaf antioxidant enzyme activity and photosynthetic pigment content of hydroponic seedlings significantly increased with the increase of dissolved oxygen concentration(P<0.05).The activities of SOD,CAT,POD and APX of hydroponic seedling leaves treated with 8 mg·L^-1 dissolved oxygen reached the peak,which were 746.13×16.67 nkat·g^-1,63.13×16.67 nkat·g^-1·min^-1,59395.45×16.67 nkat·g^-1·min^-1 and 407.46×16.67 nkat·g^-1·min^-1 respectively.Under hydroponic conditions,lysigenous aerenchyma was formed in the roots of hydroponic seedlings,and its percentage of root cross-sectional area significantly increased with the decrease of dissolved oxygen concentration(up to 7.1%),while the number of lysigenous aerenchyma changed in the opposite direction(P<0.05).[Conclusion]Under hydroponic conditions,the higher the dissolved oxygen concentration is,the better the growth of hydroponic seedlings can be.The oxygen requirement for the growth of hydroponic seedlings is greater than 8 mg·L^-1.Hypoxia can induce the formation of lysigenous aerenchyma in the root of hydroponic seedlings,but it is not enough to make it highly resistant to flooding.