植物生長促進細菌對昭和草種子發芽率與幼苗生長勢之影響

Abstract

昭和草(Crassocephalum rabens)為分布於臺灣中低海拔的一年生菊科作物，全株萃取物可被用於生產治療癌症的藥物。然而，現有的商業生產規模受種子尺寸與台灣環境溫度限制，不利於大規模及週年性生產。為此，業界正在研製昭和草披衣種子以克服種子尺寸所造成的限制。本研究將目標放在溫度對昭和草發芽表現與幼苗生長勢之影響，並期望以接種植物生長促進細菌(plant growth-promoting bacteria；PGPB)改善其種子發芽與幼苗生長勢表現。試驗材料分為披衣種子(pelleted seed)與無披衣處理種子(non-pelleted seed)，並在接種PGPB後栽種於不同環境溫度下，透過調查種子發芽表現與幼苗生長勢了解PGPB施用對昭和草之影響及其作為改善方案的潛力。試驗結果顯示，在培養皿進行的發芽試驗以30/25℃環境下培養基處理(LB)的93.33%為最高之最終發芽綠。在六、七月間於精密溫室中進行的幼苗生長勢試驗中以披衣種子土壤接種PGPB有最佳的幼苗生長勢表現；生長箱試驗中以種子接種Bacillus subtills (WO3)處理在減緩溫度對幼苗生長勢影響上有較佳表現。雖然環境溫度是影響種子發芽表現與幼苗生長勢的主要因素，但亦觀察到PGPB接種對幼苗生長勢有正向影響的趨勢。說明PGPB接種處理具有改善幼苗生長勢之潛力，未來研究可以接種菌株、接種濃度為研究主題，並對植物體中的化合物或藥用成分進行進一步的調查，以對PGPB接種所造成之影響有更明確的了解。PGPB接種則幼苗生長勢有助於改善高溫下幼苗生長勢表現，發芽表現主要受環境溫度影響。

Crassocephalum rubens, a herbaceous plant belonging to the Asteraceae family, is distributed in Taiwan’s mid to low elevations. The whole plant can be used as a vegetable, and its extract can be used for producing anticancer drugs. However, the existing commercial production scale is limited by seed size and high-temperature environments, which restricts large-scale and year-round production. The industry is developing pelleting material for C. rubens to overcome the limitation caused by the seed size. This study investigates the effects of plant growth-promoting bacteria (PGPB) inoculation on germination performance and seedling growth of C. rubens under different temperature conditions in Taiwan. The seed materials include pelleted seeds and non-pelleted seeds. The potential of PGPB for improving C. rubens growth would be evaluated by investigating how seed germination and seedling growth performance after the inoculation of PGPB. The experiments will be conducted in a greenhouse and growth chambers separately. The greenhouse experiments showed that the combination of pelleted seed and soil inoculation reached the best seedling growth performance from May to July. For the chamber experiment, seed inoculation with Bacillus subtillis mitigated the damage caused by high temperatures on seedling growth. For the results from seed germinated in the petri dish showed that the highest final germination rate (93.33%) was observed in the chamber set at 30/25℃ and inoculated with the LB medium. In conclusion, PGPB inoculation positively impacts seedling growth performance under 30/25℃ temperature conditions, while temperature was the main factor affecting germination performance. Which suggest that PGPB inoculation has the potential to improve the growth of the seedlings. Future studies can focus on finding the optimum PGPB strains or the inoculation concentration, also investigate how inoculation treatment affect the compounds inside the host plant. Which could help people understand the mechanism of PGPBs on C. rubens and make better use of them.