熱處理對草莓植株生長與生理變化之影響

Effect of Heat Treatment on the Growth and Physiological Changes in Fragaria ananassa

草莓莖頂組織培養瓶苗經38°C熱空氣處理2～4週後，其出瓶成活率可達95%，且營養生長情況良好，若將熱處理瓶苗再取莖頂培養時，有明顯促進其初期生長、側芽發生率及發根的效果。草莓組織培養苗出瓶後健化期間以熱處理6週著葉片面積最大，葉柄最長。熱處理2週者與對照差異不大。高溫長日下之營養生長並無明顯差別。開花率則以對照組最高。45°C熱水處理15分鐘會使草莓葉片及莖頂內的16種氨基酸含量增多；38°C埶空氣對氨基酸的影響則是先增加，而後減少，然後再回增。對組織培養苗莖頂而言，各種氨基酸含量皆隨熱空氣處理而增加，且此增加現象可持續四個月以上。澱粉含量變化在根部與冠芽（crown）的趨勢相同，隨處理時間，其含量先增加而後急速減少。葉片部份是先微量增加，而後維持穩定，與對照組差異不大。可溶性糖與葡萄糖、果糖含量的變化趨勢相似，在葉片是先減少，而後增加。冠芽部分是呈緩慢漸減趨勢。根部之變化則無一定規則。經過熱處理後植株各部位的蔗糖含量均呈減少之趨勢。

The growth of cultured meristem plantlets were enhanced by 38℃ hot air treatment. The response of subsequent growth vigor, multiplication and rooting rates of hot air treated meristem plantlets were affected by hot air treatment. The effects of both hot water 45℃ and hot air 38℃ on the composition of sugars, starch and amino acids have been studied. The results showed that, when tissue cultured plantlets were hot-treated at 38℃ for 2~8 weeks, the meristems subcultured from these plantlets grew faster and better at the early stage than those from untreated controls. Hot air treatment also increased the occurrence of lateral buds in cultured meristems. Plantlets heat-treated 4 weeks seemed to root most rapidly among 4 treatments (2, 4, 6 and 8 weeks). During acclimation period, 6 week hot air-treated plantlets seemed to have the largest leaf area and the longest petioles. After planting, hot air-treated plants had better vegetative growth than the control plants, while the control plants had the highest percentage of flowering. Both hot water and hot air treatments increased the amount of most amino acids in leaves and meristems except those of hot air treatment for 3 days. The content of starch in roots and crowns increased at the beginning of the treatment and dropped subsequently. There was no significant change of starch in leaves. The patterns of changes in total soluble sugars, glucose and fructose were similar. There were slight changes in these 3 components except at the beginning of heat treatment, where a decrease was found in leaves. The content of these components decreased slowly, and no regular pattern of changes of sugars appeared in crown.