4种激素浸种对南极假山毛榉萌发与幼苗生长的影响

Influence of Four Hormones on Germination and Seedling Growth of Nothofagus antarctica

南极假山毛榉是优良的用材和景观树种,但是种子的自然发芽率极低。为了筛选出既能高效解除南极假山毛榉种子休眠,又有利于幼苗生长的浸种外源激素,采用不同浓度的硝普钠(SNP)、乙烯利(EHT)、赤霉素3(GA3)和丙二酸(MA)浸泡南极假山毛榉种子24h,观测了从种子萌发到幼苗形态建成的8项指标(发芽率、株高、地径、叶面积、相对叶绿素含量、根系总长度、根系总表面积和根尖数量)变化,并应用灰色关联分析和因子分析进行综合评价。结果表明,低浓度(≤4 000mg/L)SNP处理能显著提高种子发芽率,6 000mg/L的EHT、GA3和MA处理具有显著的抑制萌发效应;SNP能明显增加根系总长度,随着浓度增加,各项指标呈先增后减的变化趋势;EHT浓度增加导致各项生长指标呈现下降趋势;GA3浓度增加引起幼苗株高增长,其他生长指标却低于对照;MA处理的多项生长指标的最大值出现在2 000mg/L浓度时。灰色关联度分析和因子分析表明,用4 000mg/L的SNP浸种24h既能获得相对较高的发芽率,又能促进幼苗生长,是解除南极假山毛榉种子休眠的最优方法。

Nothofagus antarcticais an excellent timber and ornamental tree species,but its seed germination rate is very low under natural conditions.To select the optimum exogenous hormones which can not only effectively relieve the dormancy of the N.antarcticaseeds,but also help the seedlings to successfully complete the morphogenesis.This research adopted different concentrations of sodium nitroprusside(SNP),ethephon(EHT),gibberellin 3(GA3)and moronic acid(MA)to soak the N.antarcticaseeds for24 h,and 8 indexes(germination percentage,plant height,ground diameter,leaf area,relative chlorophyll content,total root length,total root surface area and root tip number)of the seedlings were treated with grey relativity analysis and factor analysis.The results showed that low concentration(≤4 000 mg/L)of SNP treatment could significantly increase the seed germination rate,and EHT,GA3 and MA treatment with 6 000 mg/L had significant inhibitory effect on germination.SNP could significantly increase the total root length,and as the concentration increased,most indexes showed a trend of first increasing and then decreasing.The increase of EHT concentration caused growth indicators decreased.The increase of GA3 concentration caused the growth of the seedlings,but the other growth indicators were lower than the control group.MA treatment reached the maximum value of growth indicators at 2 000 mg/L.The grey correlation analysis and factor analysis showed that soaking seeds with 4 000 mg/L of SNP could not only obtain relatively high germination rate,but also improve seedling growth,which was the optimal way to relieve the dormancy of the N.antarcticaseeds.