石榴耐盐性研究与指标筛选

以3个石榴Punica granatum品种的扦插苗为材料，研究不同浓度（0，150，300，450 mmol·L-1）氯化钠胁迫对各品种生长和生理生化指标的影响，并筛选适合评价石榴耐盐性的指标。结果表明:与对照相比，‘红珍珠’ ‘Hongzhenzhu’的生物量随氯化钠浓度升高而降低，而低盐胁迫（150 mmol·L-1）下，‘泰山红’ ‘Taishanhong’和‘超大籽’ ‘Chaodazi’的生物量增加。随着盐浓度增大，各石榴品种盐害加重；单位质量新鲜叶片中叶绿素质量分数降低；脯氨酸质量分数、丙二醛质量摩尔浓度、钠离子质量分数升高；可溶性蛋白质质量分数先降低后升高；超氧化歧化酶（SOD），过氧化氢酶（CAT）酶活性和钾离子质量分数先升高后降低，300 mmol·L-1处达到最大值；氯化钠浓度不超过300 mmol·L-1时，钾钠离子比均大于1。研究说明:石榴能够抵抗中度盐胁迫（≤ 300 mmol·L-1），主要通过增加脯氨酸、钾离子等渗调物质质量分数和提高抗氧化酶活性来缓解盐害。灰色关联分析筛选出单株生物量、SOD酶活性、盐害指数、钾钠离子比值和丙二醛质量摩尔浓度作为评价石榴耐盐性的主要指标。

Salt tolerance and screening for identification indexes with pomegranate cuttings

To choose suitable indexes for evaluating salt resistance in pomegranates (Punica granatum), cuttings from three pomegranates cultivars:'Tanshanhong', 'Chaodazi', and 'Hongzhenzhu' were selected as materials. Effects on growth, physiological, and biochemical indexes were observed after CRD design treatments of 0, 150, 300, and 450 mmol·L-1 NaCl, each block was 5 pots and 3 replications. The analysis of variance (ANOVA) and Duncan multiple comparison were determined at P=0.05 level. Results showed that biomass of 'Tanshanhong' and 'Chaodazi' increased by 21% and 18% at low salinity (150 mmol·L-1), but that of 'Hongzhenzhu' decreased. With the increased NaCl concentration, salt injury was aggravated; chlorophyll content decreased; proline, malondialdehyde, and Na+ content increased; soluble protein content of the three cultivars all first decreased and then increased; the activities of superoxide dismutase (SOD), catalase (CAT), and K+ content first rose and then dropped with maximums at 300 mmol·L-1 NaCl; and K+/Na+ was greater than 1 at moderate salinity level (≤ 300 mmol·L-1). Thus, pomegranates could alleviate salt stress by increasing the content of osmoregulating substances and improving antioxidant enzyme activities in moderate salinity with seven crucial indexes for evaluating pomegranate salt tolerance being biomass, salt injury index, SOD, K+/Na+, Na+, K+, and MDA content.