碳酸氢盐处理下桑树和构树的生长、光合和抗逆性差异

为探究喀斯特生境中,在碳酸氢盐的胁迫下HCO^-₃对植株生长及生理特性的影响,该文以构树和桑树幼苗为研究对象,对不同浓度NaHCO₃溶液(0、15、30 mmol·L^-1)处理下植株的生长情况、光合能力、抗氧化酶活性、渗透调节物质含量和细胞膜系统损伤情况进行研究。结果表明:(1)在HCO^-₃处理下,构树和桑树的生长和光合能力均受到抑制,叶片细胞内均发生显著的抗氧化和抗渗透胁迫生理响应。(2)HCO^-₃对构树和桑树生长的抑制作用与其浓度有关,并有显著差异性(P<0.05)。(3)30 mmol·L^-1 HCO^-₃处理对植株生长、光合、抗氧化酶系统和渗透调节系统的抑制作用以及植物细胞的损伤情况要显著强于15 mmol·L^-1 HCO^-₃处理的效果。(4)同等浓度的HCO^-₃处理下,构树的生长、光合能力、抗氧化酶活性、渗透调节物质含量显著高于桑树,其叶片细胞损伤情况显著低于桑树。综上结果均表明,构树对碳酸氢盐胁迫的耐受能力要优于桑树。该研究为阐明桑科植物对喀斯特环境适应机制提供科学支撑。

Differences in growth, photosynthesis and resistance physiology of Morus alba and Broussonetia papyrifera under bicarbonate treatments

To investigate the effects ofHCO^- ₃ on the growth and physiological characteristics of plants under the stress of bicarbonate in karst environment. The growth, photosynthetic capacity, antioxidant enzyme activity, osmotic regulation substance content and cell membrane damage of Broussonetia papyrifera and Morus alba seedlings under three different concentrations of NaHCO₃(0, 15, 30 mmol·L^-1, respectively)were examined in the present study. The results were as follows:(1)Under HCO^-₃ treatment, the growth and photosynthetic capacity of Broussonetia papyrifera and Morus alba seedlings were significantly inhibited, accompanying the physiological responses of leaf cells to antioxidant and osmotic stress were significant.(2)The inhibitory effects of HCO^-₃ on the growth of Broussonetia papyrifera and Morus alba were concentration-dependent, and showed significant differences among examined concentrations(P<0.05).(3)The inhibitory effects of the growth, photosynthesis, antioxidant enzyme system and osmotic regulation system and the damage of plant cells under 30 mmol·L^-1HCO^- ₃treatment were significantly stronger than those of 15 mmol·L^-1HCO^-₃ treatment.(4)Under the same concentration of HCO^-₃, the growth, photosynthetic capacity, antioxidant enzyme activity, osmotic regulating substance content of Broussonetia papyrifera were significantly higher than those of Morus alba, and its leaf cell damage was significantly lower than that of M. alba. The results mentioned above indicate that HCO^- ₃ inhibits the growth, photosynthesis and resistance physiology of M. alba and Broussonetia papyrifera under bicarbonate stress, and the tolerance of B. papyrifera to bicarbonate stress is better than that of Morus alba, which means that Broussonetia papyrifera is more adaptable to the environment of bicarbonate stress. This study provides scientific support for the adaptation mechanism of Moraceae to karst environment.