| Autor: |
Fujita K; Graduate School of Biosphere Sciences, Hiroshima University, 1-4-4 Kagamiyama, Higash-hiroshima, 739-8528, Japan. Corresponding author; email: fujiko@hiroshima-u.ac.jp., Ito J; Hiroshima Prefectural Agricultural Center, Hara, Hachihonmatsu, Higashi-hiroshima, 736-0151 Japan., Mohapatra PK; School of Life Science, Sambalpur University, Jyoti vihar, Sambalpur 768019, India., Saneoka H; Graduate School of Biosphere Sciences, Hiroshima University, 1-4-4 Kagamiyama, Higash-hiroshima, 739-8528, Japan., Lee K; Graduate School of Biosphere Sciences, Hiroshima University, 1-4-4 Kagamiyama, Higash-hiroshima, 739-8528, Japan., Kurban H; School of Life Science, Sambalpur University, Jyoti vihar, Sambalpur 768019, India., Kawai K; Keisoku Engineering Company, 23-9 Kamishinonome-cho, Minami-ku, Hiroshima, 734-0021, Japan., Ohkura K; Faculty of Environmental and Information Sciences, Yokkaichi, 512-8512, Japan. |
| Abstrakt: |
Early diagnosis of water deficiency is essential to mitigate salt stress injury in plants. The effects of salt stress during the fruit growth stage on stem and fruit diameters of Japanese persimmon trees (Diospyrus kaki Thunb.) were measured by a micromorphometric technique under greenhouse conditions. This technique is less cumbersome and more precise in comparison to measurement of water potential in a small pressure chamber. The effect of stress was measured on photosynthetic rate, pre-dawn water potential, stomatal conductance, transpiration and Na + and K + contents of the stem and leaves. Salt stress was imposed by irrigating the plants with NaCl solution. Stem and fruit diameters of the plants given the control treatment started to decrease around 0600 h and reached a minimum at 1400 h. Salt stress did not change the diurnal pattern of response in stem and fruit diameter dynamics, but decreased the amplitude of the circadian rhythm by influencing both declining and recovery phases. The effect of salt stress on stem diameter appeared after 1 d of treatment, and on the third day in the fruit. Salt stress also reduced water potential, photosynthesis, transpiration and stomatal conductance, and increased concentrations of Na and K in the plant parts. Most of these effects were expressed after a lag period of 5 d of salt application. Utilization of micromorphometric techniques for early diagnosis of water deficiency in salt-prone environments is recommended based on results of this study. |
