토양수분함량이 지황 ‘토강 ’의 생육 , 광합성 및 항산화효소 활성에 미치는 영향 (Effect of Soil Water Status on Growth, Photosynthesis, and Antioxidant Enzyme Activity in Rehmannia glutinosa var. ‘Togang’)

서지정보

· 발행기관 : 한국약용작물학회
· 수록지 정보 : 한국약용작물학회지 / 31권 / 4호 / 235 ~ 246페이지
· 저자명 : 권아름, 장원석, 김선익, 성봉재, 곽성희

초록

Background: Rehmannia glutinosa, a rhizomatous herbaceous perennial plant, is widely used as a medicinal plant in the Far East region. Although the influence of waterlogging on the growth and yield of R. glutinosa has been evaluated, few studies have focused on how these plants respond to a wide range of soil water status including wet and dry conditions, in terms of growth and physiolog- ical characteristics. Therefore, this study investigated the effect of contrasting soil moisture regimes on the growth, photosynthesis, chlorophyll fluorescence, antioxidant enzyme activity, and bioac- tive compound content in R. glutinosa var. ‘Togang’.
Methods and Results: Potted ‘Togang’ plants were irrigated according to five different soil water statuses, −10, −20, −30, −40, and −50 ㎪, with each moisture level controlled using tensiom- eters throughout the experiment. The effects on sprouting rate from rhizome propagules, vegetative growth, rhizome yield, photosynthetic characteristics, antioxidant enzyme activity, and rhizome catalpol content were determined. A significant reduction in the sprouting rate of propagules and vegetative growth (leaf number and growth) was found when plants were irrigated at −50 ㎪. Yield components such as the number of rhizomes and the total and marketable weights of rhizomes were the highest at the −30 ㎪ treatment. Although the total rhizome weight in the −10 ㎪ and −20 ㎪ treatments was as high as that in the -30 ㎪ treatment, the marketable weight was significantly reduced because root rot occurred under these high moisture conditions; root rot decay was the highest at −10 ㎪ (7.6% of total rhizome weight), followed by 5.3% at −20 ㎪, whereas it was neg- ligible in the range of −30 ㎪ and −50 ㎪ soil water status. Regarding water stress-induced antioxi- dant levels, the superoxide dismutase, peroxidase, and catalase activities increased when the plants were stressed with water excess (−10 ㎪) or shortage treatment (−50 ㎪), compared to those with the −30 ㎪ treatment. The net photosynthesis and transpiration rates were considerably higher at −20 ㎪ and −30 ㎪ than those at the other treatments. Chlorophyll fluorescence measurements showed that the −20 ㎪ and −30 ㎪ treatments showed a maximum quantum yield (Fv/Fm) of higher than 0.8 (considered as the stress threshold), whereas the −10 ㎪ or −50 ㎪ treatments showed a quantum yield of less than 0.8. The content of catalpol, a bioactive compound in rhi- zomes, was the highest at −30 ㎪ (35.9 ㎎/g FW).
Conclusions: Considering its effect on vegetative growth, yield, some physiological characteristics (photosynthesis and chlorophyll florescence), and rhizome catalpol content, our results indicate that approximately −30 ㎪ of soil water potential is the appropriate soil water status for cultivating Rehmannia glutinosa var. ‘Togang’.

영어초록

Background: Rehmannia glutinosa, a rhizomatous herbaceous perennial plant, is widely used as a medicinal plant in the Far East region. Although the influence of waterlogging on the growth and yield of R. glutinosa has been evaluated, few studies have focused on how these plants respond to a wide range of soil water status including wet and dry conditions, in terms of growth and physiolog- ical characteristics. Therefore, this study investigated the effect of contrasting soil moisture regimes on the growth, photosynthesis, chlorophyll fluorescence, antioxidant enzyme activity, and bioac- tive compound content in R. glutinosa var. ‘Togang’.
Methods and Results: Potted ‘Togang’ plants were irrigated according to five different soil water statuses, −10, −20, −30, −40, and −50 ㎪, with each moisture level controlled using tensiom- eters throughout the experiment. The effects on sprouting rate from rhizome propagules, vegetative growth, rhizome yield, photosynthetic characteristics, antioxidant enzyme activity, and rhizome catalpol content were determined. A significant reduction in the sprouting rate of propagules and vegetative growth (leaf number and growth) was found when plants were irrigated at −50 ㎪. Yield components such as the number of rhizomes and the total and marketable weights of rhizomes were the highest at the −30 ㎪ treatment. Although the total rhizome weight in the −10 ㎪ and −20 ㎪ treatments was as high as that in the -30 ㎪ treatment, the marketable weight was significantly reduced because root rot occurred under these high moisture conditions; root rot decay was the highest at −10 ㎪ (7.6% of total rhizome weight), followed by 5.3% at −20 ㎪, whereas it was neg- ligible in the range of −30 ㎪ and −50 ㎪ soil water status. Regarding water stress-induced antioxi- dant levels, the superoxide dismutase, peroxidase, and catalase activities increased when the plants were stressed with water excess (−10 ㎪) or shortage treatment (−50 ㎪), compared to those with the −30 ㎪ treatment. The net photosynthesis and transpiration rates were considerably higher at −20 ㎪ and −30 ㎪ than those at the other treatments. Chlorophyll fluorescence measurements showed that the −20 ㎪ and −30 ㎪ treatments showed a maximum quantum yield (Fv/Fm) of higher than 0.8 (considered as the stress threshold), whereas the −10 ㎪ or −50 ㎪ treatments showed a quantum yield of less than 0.8. The content of catalpol, a bioactive compound in rhi- zomes, was the highest at −30 ㎪ (35.9 ㎎/g FW).
Conclusions: Considering its effect on vegetative growth, yield, some physiological characteristics (photosynthesis and chlorophyll florescence), and rhizome catalpol content, our results indicate that approximately −30 ㎪ of soil water potential is the appropriate soil water status for cultivating Rehmannia glutinosa var. ‘Togang’.

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