低温胁迫下不同浓度ABA对4个油棕新品种幼苗生理特性的影响

Effects of Exogenous ABA on Physiology of Four New Oil Palm Varieties under Cold Stress

探讨低温胁迫下不同品种油棕幼苗ABA合成酶基因NCED3表达特性及不同浓度ABA对其幼苗生长和生理的影响,为提高不同品种油棕幼苗抗寒能力提供理论依据。以油棕新品种Ni、C×N、B×E、D×N为材料,对其进行低温胁迫处理(15、10、5℃,5 d),利用实时荧光定量PCR(qPCR)检测4种油棕幼苗的NCED3基因表达特性;然后,10℃低温胁迫下对4种油棕幼苗外施不同浓度ABA(50~300μmol/L ABA),测定其可溶性蛋白、可溶性糖、脯氨酸含量和超氧化物歧化酶(SOD)及过氧化物酶(POD)活性等生理指标。结果表明,低温胁迫可触发4种油棕幼苗ABA合成酶基因NCED3的过量表达,外施50~300μmol/L ABA均降低幼苗质膜透性和SOD酶活性,抑制MDA和H2O2含量上升,缓解低温胁迫引起的膜脂过氧化,提高可溶性蛋白、可溶性糖含量和POD活性,进而提高油棕幼苗抗寒性。4个品种中,B×E材料的耐寒能力较强。

In order to provide theoretical basis for improving cold resistance of different oil palm varieties, the present experiment was conducted to investigate the expression characteristics of ABA synthase gene NCED3 of different oil palm varieties under cold stress and the growth and physiology effects of different ABA concentrations on cold resistance of different oil palm varieties. The new oil palm varieties Ni, C×N, B×E and D×N were used as the materials, treated with low temperature stress(15 ℃, 10 ℃, 5 ℃, 5 d). The expression characteristics of NCED3 in the seedlings were detected by real-time quantitative PCR(qPCR). Then, different concentrations of ABA(50-300 μmol/L ABA) were applied to the seedlings under 10 ℃, and the physiological indexes were determined, including soluble protein content, soluble sugar content, proline content, H2O2 content, MDA content, SOD and POD activity. Cold stress could trigger the overexpression of ABA synthase gene NCED3 in the seedlings. The application of 50-300 μmol/L ABA decreased the plasma membrane permeability and SOD activity of the seedlings, inhibited the increase of MDA and H2O2 levels, so the membrance lipid peroxidation caused by cold stress was relieved, soluble protein, soluble sugar content and POD activity were increased, and thus improved cold resistance of the seedlings. B×E had strong cold tolerance.