混合盐碱胁迫下外源茉莉酸甲酯对黑果枸杞种子萌发特性的影响

Effects of exogenous methyl jasmonate on the seed germination characteristics of Lycium ruthenicum under mixed saline-alkali stress

摘要:

为明确外源茉莉酸甲酯(MeJA)对混合盐碱胁迫下黑果枸杞种子萌发特性的影响，以黑果枸杞种子为试验材料，采用纸上萌发法，研究了混合盐碱胁迫下施加外源 MeJA 后黑果枸杞种子萌发进程、发芽率(GP)、发芽势(GR)、发芽指数(GI)、活力指数(VI)、异状发芽率(HGP)、茎长(LS)、根长 (LR)及萌发期幼苗生长表型变化。结果显示：(1)中性混合盐(L)和中度碱性混合盐(M)在适当低、中浓度时能在一定程度上加速黑果枸杞种子萌发，重度碱性混合盐(H)则使黑果枸杞的萌发起始时间延后，萌发总时长缩短；MeJA 对混合盐碱胁迫下黑果枸杞种子萌发起止时间和发芽延续时间没有明显影响；(2)GP、GR、GI、VI、LS、LR 在中性混合盐(L)、中度(M)和重度(H)碱性混合盐处理时均随盐碱浓度升高呈逐渐降低趋势；外源 MeJA 对混合盐碱胁迫下黑果枸杞种子的萌发存在“低促高抑”现象， 适当低、中浓度起促进作用，过高浓度则抑制；(3)生长表型(长势)随盐碱浓度及碱性盐占比升高明显减弱；适当浓度外源 MeJA(MJ-10、MJ-20)能在一定程度上缓解盐碱胁迫对幼苗生长的伤害，过高浓度外源 MeJA(MJ-40、MJ-80)则使伤害加剧。综上：不同盐碱组成及盐碱浓度胁迫对黑果枸杞种子萌发具有不同程度的抑制作用，碱性盐占比和盐碱浓度越高，抑制作用越强；MeJA 对混合盐碱胁迫下黑果枸杞种子萌发的伤害缓解有明显剂量效应，适当低中浓度 MeJA 起缓解作用，过高浓度则使伤害加剧，以 20 μmol/L 的综合缓解效果最佳。本研究为盐碱地发展黑果枸杞小浆果产业和盐碱荒漠化治理提供了一种新的思路。

Abstract:

In order to clarify the effect of exogenous methyl jasmonate (MeJA) on the germination characteris- tics of Lycium ruthenicum seeds under mixed saline-alkali stress，this study used Lycium ruthenicum seeds as the ex- perimental material and used the paper germination experiment to study the L. ruthenicum seed germination process， germination percentage(GP)，germination rate(GR)，germination index(GI)，vigor index(VI)，heteromorphic germi- nation percentage(HGP)，length of stem(LS)，length of root(LR) and phenotypic changes of seedling growth in dur- ing germination under mixed saline - alkali stress. The results showed that：(1) Neutral mixed salt (L) and moder- ately alkaline mixed salt (M) can accelerate the germination of L. ruthenicum seeds to a certain extent at moderately low and medium concentrations，while the germination initiation time of L. ruthenicum was delayed and the total ger- mination time was shortened by heavy alkaline salt (H). MeJA has no significant effect on the germination start and stop time and the duration of germination of L. ruthenicum seed under mixed saline-alkali stress.(2) The GP，GR，GI and VI of seeds and LS and LR of seedlings of L. ruthenicum were decreased gradually with the increase of salt and alkali concentration when treated with neutral (L)，moderate (M) and severe (H) alkaline mixed salts. Exogenous MeJA had a phenomenon of "low promotion and high inhibition" on GP，GR，GI and VI of L. ruthenicum seeds and LS and LR of L. ruthenicum seedlings under mixed salt-alkali stress. Appropriate low and medium concentration will promote the effect，while excessive concentration will inhibit the effect.(3)The growth phenotype decreased sig- nificantly with the increase of salt and alkali concentration and proportion of alkaline salt. Exogenous MeJA(MJ-10， MJ-20) with appropriate concentration can alleviate the damage of saline-alkali stress on seedling growth to a certain extent，while excessively high concentration of exogenous MeJA(MJ-40，MJ-80) can aggravate the damage. In sum- mary，different salt- alkali composition and salt- alkali concentration stress have different degrees of inhibition on the seed germination of L. ruthenicum. The higher the proportion of alkaline salt and the salt - alkali concentration，the stronger the inhibition. MeJA has a significant dose effect on the injury mitigation of the seed germination of L. ru- thenicum under the mixed salt - alkali stress. Appropriate low and medium concentration of MeJA can alleviate the damage，while the excessive concentration will aggravate the damage，the comprehensive alleviation effect of 20 μmol/L is the best. This research provides a new idea for the development of small berry industry of L. ruthenicum and the control of saline-alkali desertification in saline-alkali land.