P-V 곡선법에 의한 참취와 수리취의 수분포텐셜 비교

Comparison of Water Potential Parameters in Aster scaber and Synurus deltoides Leaves Obtained from P-V Curves

P-V 곡선을 적용하여 참취와 수리취의 수분특성인자를 측정한 결과 최대포수시의 삼투포텐셜 Ψosat과 초기원형질분리점의 삼투포텐셜 Ψotlp은 참취가 수리취보다 낮은 값을 나타냈으나 큰 차이를 보이지는 않았다. 최대팽압 ΨP, max는 참취가 수리취에 비해 높게 나타났으며, 최대탄성계수 Emax는 참취가 수리취에 비해 약 2.4배 정도 높은 값을 나타냈다. 초기원형질분리점에서의 상대함수율 RWCtlp은 참취와 수리취 모두 90% 이상의 함수율을 보여 비교적 삼투조절기능이 좋은 것을 알 수 있었고, apoplastic water의 비율은 참취가 더 크며, Vo/DW, Vt/DW, Ns/DW은 수리취가 참취에 비해 약 1.5~2.0배 정도 큰 경향을 보였다. 위 결과를 통해 참취와 수리취 모두 초기원형질분리점과 최대포수시의 삼투포텐셜이 높은 편으로 내건성은 비교적 약한 것으로 나타났으며, 습윤한 지역이 생육에 적합함을 알 수 있었다. 또한, 참취와 수리취를 비교할 때 참취가 수리취에 비해 건성잎의 특성을 가지고 있으며, 최대탄성계수와 삼투포텐셜이 높아 내건성이 약간 더 강한 것을 알 수 있었다.

This study was carried out to establish a proper cultivation site and diagnose the drought-tolerance of Aster scaber and Synurus deltoides leaves by using Pressure-volume curves. In order to measure pressure-volume (P-V) curves, Aster scaber and Synurus deltoides were cut off above ground part and the tip of the cutting were placed in water, which was covered with a plastic bag. Samples were kept overnight (about 12 hours) in darkness at room temperature (20~25℃) to achieve maximal turgor (full saturation). The pressure in the chamber was gradually increased from 0.3MPa to 1.8MPa by nitrogen gas. After measured, leaf samples were dried at 80℃ for 48 hours and dry weight of each samples were determined. The result of the original bulk osmotic potential at maximum turgor Ψosat was lower -0.8 MPa in Aster scaber leaves than -0.7 MPa Synurus deltoides leaves. Also the osmotic potential at incipient plasmolysis Ψotlp in Aster scaber leave was -0.9 MPa. In contrast, the value of maximum bulk modulus of elasticity Emax of Aster scaber leaves were approximately two folds higher than that of Synurus deltoides leaves. The values of the relative water content at incipient plasmolysis RWCtlp are all above 90% showing that the function of osmoregulation is somewhat better, and Vo/DW, Vt/DW, Ns/DW of Synurus deltoides leaves were approximately 1~2 times higher than that of Aster scaber leaves. Thus, responses to water relations of Aster scaber and Synurus deltoides such as Ψosat, Ψotlp, Emax, ΨP, max, RWCtl were shown that the Aster scaber leaves was slightly higher drought- tolerance than Synurus deltoides leaves. However, in both of Aster scaber and Synurus deltoides, occurring incipient plasmolysis at the high water content, have a relatively lower drought-tolerance property indicating that growth of these plants are cultivated appropriate in high moisture soil sites.