摘要
以绿豆种子为材料，研究种子吸胀过程中的萌发行为、脱水耐性的变化以及不同脱水速率对脱水耐性丧失的影响．在吸胀过程中，种子含水量迅速增加，不表现出典型的吸水三阶段模式；种子的电解质渗漏速率和相对电导率显著增加直到３ｈ，然后下降．５０％种子萌发需要的时间和热时间分别是５．５ ｈ和 ７ ℃ｄ．在种子预吸胀过程中，种子的脱水耐性和由脱水后存活种子产生的幼苗生长量逐渐下降，５０％种子丧失脱水耐性的时间是７ｈ，以及脱水后种子的电解质渗漏明显增加．下胚轴的脱水耐性大于胚根．吸胀１２ｈ的绿豆种子对脱水非常敏感；缓慢脱水时，５０％种子丧失脱水耐性的水分含量（以干质量计）为０．１５ ｇ．ｇ～（－１）．根据水分含量对存活率、幼苗生长和电解质渗漏的影响，缓慢脱水比快速脱水好．这些结果表明，吸胀的绿豆种子脱水耐性的丧失是一种数量特征，吸胀的正常性种子脱水耐性的变化可以作为种子顽拗性研究的一个模式系统．
Mung been (Phaseolus radiatus L.) seeds were used as experimental material. Germination behaviour and changes in desiccation tolerance of seeds during imbibition, and effect of different dehy- dration rate on desiccation tolerance were studied. Water uptake by seeds rapidly increased with imbi- bition, and did not exhibited a typical triphasic pattern of water uptake. Rate of electrolyte leakage and relative leakage from seeds dramatically increased up to 3 h of inibibition, and then declined. The time and thermal time required for 50% germination seeds were 5.5 h and 7 degree days, respectively. During pre-imbibition of seeds, desiccation tolerance of seeds and seedling growth rate produced by survival seeds was progressively decreased, and imbibition time at which 50% of seeds were lost dehy- dration tolerance was 7 h, and electrolyte leakage from seeds which were pre-inibibed and consequently dehydrated significantly increased. Desiccation tolerance of hypocotyl was larger than that of radicle. Mung been seeds imbibed for 12 h were very sensitive to desiccation. Water content at which 50% seeds were killed by dehydration was 0. 15 g H2O g^(-1) DW as dehydration rate was slow. On the basis of the influence of water content on survival, seedling growth and electrolyte leakage, slow dehydration was better than rapid dehydration. The results showed that the loss of desiccation tolerance of imbibed mung been seeds was a quantitative feature, and that the changes in desiccation tolerance of imbibing orthodox seeds could serve as a model system for the study of seed recalcitrance.
出处
《中山大学学报（自然科学版）》
CAS
CSCD
北大核心
2000年第z2期104-111,共3页
Acta Scientiarum Naturalium Universitatis Sunyatseni
基金
国家教育部留学回国人员科研启动基金资助项目
国际植物遗传资源研究所(IPGRI) 基金资助项目
关键词
脱水
脱水耐性
萌发活性
吸胀
正常性种子
绿豆
dehydration
desiccation tolerance
germination activity
imbibition
orthodox seed
Phaseolus radiatus L.
