| Effects of drought on physiological characteristics and potassium content of flue\|cured tobacco seedlings under low potassium stress |
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| DOI：10.7606/j.issn.1000-7601.2023.04.19 |
| Key Words: flue\|cured tobacco seedlings low potassium drought stress resistance physiology plant potassium content |
| Author Name | Affiliation | | SHI Qiuhuan | Luoyang City Company, Henan Tobacco Company, Luoyang, Henan 471023, China | | XU Gaoqiang | Fujian Jinmin Reconstructed Tobacco Development Co., Ltd., Fuzhou, Fujian 350600, China | | DAI Xiaoyan | College of Tobacco Science, Henan Agricultural University, Key Laboratory for Tobacco Cultivation in Tobacco Industry, Zhengzhou, Henan 450002, China | | ZHANG Tongjin | College of Tobacco Science, Henan Agricultural University, Key Laboratory for Tobacco Cultivation in Tobacco Industry, Zhengzhou, Henan 450002, China | | CHEN Peiyu | College of Tobacco Science, Henan Agricultural University, Key Laboratory for Tobacco Cultivation in Tobacco Industry, Zhengzhou, Henan 450002, China |
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| Abstract: |
| To investigate the effects of different drought levels on physiological characteristics and potassium uptake of flue\|cured tobacco seedlings under low potassium stress, flue\|cured tobacco variety K326 was used as the experimental material and the physiological indexes, photosynthetic characteristics and potassium content of each part of the tobacco plant were measured by indoor hydroponics. A two\|factor design was used with different potassium levels (low potassium 0.15 mmol·L-1 and normal potassium 5.00 mmol·L-1) and simulated drought degree with PEG-6000 (concentration 0, 5%, 10%, 15%, 20%, respectively). The results showed that at the lower potassium level, the dry and fresh weight of above\|ground part and root of tobacco seedlings, root activity, photosynthetic indexes of leaf (except intercellular CO2 concentration and water vapor pressure saturation deficit) and potassium content in all parts of tobacco plants were lower than that at the normal potassium level under the same PEG-6000 concentration.The potassium content in above\|ground part and root of tobacco plant under low potassium stress decreased by 10.62%~21.70% and 35.96%~58.82% compared with normal potassium level, respectively. At normal potassium level, with the increase of PEG-6000 concentration, root dry weight, root activity, leaf net photosynthetic rate, stomatal conductance, water utilization, leaf soluble protein content, POD and CAT activities of tobacco plant first increased and then decreased. And all of these indexes achieved the maximum value when PEG-6000 concentration was 10%.Compared with PEG-6000 concentration 0 treatment, the increases were 16.01%, 131.66%, 27.87%, 73.68%, 78.57%, 44.13%, 179.11% and 49.21%, respectively. Under low potassium stress, the dry and fresh weight of all parts of tobacco and photosynthetic characteristics of tobacco leaves were significantly reduced after the addition of PEG, in which the net photosynthetic rate, stomatal conductance, transpiration rate and water utilization were reduced by 56.25%, 41.94%, 57.14% and 36.90% in the PEG-6000 concentration 20% treatment compared with 0 PEG concentration. The relative conductivity, hydrogen peroxide, superoxide anion and malondialdehyde contents in tobacco leave gradually increased with the increase of PEG-6000 concentration. Compared with PEG concentration 0 treatment, and they increased by 20.45%~108.55%, 34.53%~197.61%, 67.38%~106.24%, 10.98%~69.80% respectively. Under the two potassium levels, the potassium content in all parts of the plant gradually decreased with the increase of PEG-6000 concentration. When the PEG-6000 concentration was 20%, the potassium content in aboveground part and root of tobacco plants at normal level decreased by 63.44% and 40.66% compared with the treatment of PEG concentration 0, while that decreased by 76.49% and 34.39% at low potassium level. In summary, drought stress significantly inhibited the growth and development of flue\|cured tobacco at low potassium level, while increasing potassium levels alleviated the damage caused by drought stress by enhancing root activity and photosynthesis and reducing leaf reactive oxygen content to improve the overall drought resistance of flue\|cured tobacco.However, when drought stress was severe to a certain extent, potassium level was not able to alleviate the adverse effects of drought on growth and physiology of flue\|cured tobacco. |
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