S-Space College of Agriculture and Life Sciences (농업생명과학대학) Dept. of Plant Science (식물생산과학부) Theses (Ph.D. / Sc.D._식물생산과학부)
Non-destructive Measurement of Plant Internal Electrical Conductivity of Hydroponically Grown Paprika
수경재배 파프리카의 비파괴적 식물 내부 전기전도도 측정
- 농업생명과학대학 식물생산과학부(원예과학전공)
- Issue Date
- 서울대학교 대학원
- 학위논문 (박사)-- 서울대학교 대학원 : 농업생명과학대학 식물생산과학부(원예과학전공), 2018. 8. 손정익.
- The electrical properties of plant stems represent physiological activities in-cluding water and ion transport. Plant responds to changes in environmental condition, which can be reflected in internal electrical conductivity of plant stems (ECps). Therefore, monitoring of ECps may help understand the plant physiological changes related to environmental stress. Because direct and stable measurement of ECps was very difficult, complicated, and expensive, the ECps could not be easily adapted to monitor plant responses to stressed environmental conditions. The objectives of this study were to develop a stable and simple measuring method of internal ECps and investigate the re-lationship between the ECps and environmental factors in greenhouse. Two electrodes with three needles were inserted into both sides of paprika stem to monitor paprika ECps and stable ECps was acquired. Environmental fac-tors such as temperature, irradiance, and relative humidity were recorded and compared with the ECps. The ECps was positively correlated with light intensity and temperature (R2=0.642 and 0.815, respectively), while nega-tively correlated with relative humidity (R2=-0.416). The ECps was predicted using a regressed equation describing environmental data, and the predicted ECps corresponded well to measured ones. The ECps was higher during the day than at night, which was attributed to higher daytime water content in the stems. The ECps was better correlated with water content than ion con-centrations in the stem. To use ECps for monitoring of paprika responses to environmental stress, relationship of ECps with plant physiological responses was established. The relationships between ECps and photosynthetic re-sponses of paprika as well as sap flow were evaluated. Monitoring of papri-ka ECps relative to various environmental conditions such as low irradiance and water shortage showed that plant responses to environmental stress could be explained by changes in ECps. High ECps was related to high pho-tosynthetic rate, stomatal conductance, and transpiration rate. Sap flow of the plant was also associated with ECps, with a correlation coefficient of 0.606. However, the sap flow reflected only water flux, while ECps was de-termined by both water and ion contents in stem of paprika. Comparison of measured and predicted ECpss could be used to detect unusual cultivation conditions of paprika. Plant responses to water shortage could be reflected on lower ECps compared with predicted value. Therefore, continuous moni-toring of ECps can be used to detect plant responses to water stress. In order to use this method in the field, it will be necessary to test and develop field application techniques through further experiments such as comparison with sap flow.
- Files in This Item: