Changes in Invertase Activities during Hardening to Hypothermia of Nicotiana tabacum L. and Arabidopsis thaliana Heynh. (L.)
2021
Popov, V. N. | Astakhova, N. V.
Changes in invertase activities were studied upon hardening of chilling-sensitive (Nicotiana tabacum L.) and cold-resistant (Arabidopsis thaliana Heynh. (L.)) plants to hypothermia. In tobacco plants, the activity of cytoplasmic and vacuolar invertases was found to decrease by 20% during hardening, while the activity of cell wall invertase increased almost twofold. In arabidopsis, the activity of all three types of invertases increased more than twofold during hardening. The hardened tobacco plants showed a 20% increase in sugar content, while the relative content of sucrose and hexoses (fructose and glucose) in sugars did not change after hardening and equaled approximately 50% each. During hardening of arabidopsis plants, the sugar content increased 2.5 fold, whereas the proportion of sucrose in the total sugar content decreased (from 44 to 24%) and the proportion of hexoses increased (from 56 to 76%). It was proposed that the increase in activity of cell wall invertase in both plant species suppressed the outflow of assimilates and facilitated the accumulation of photosynthates in mesophyll cells of tobacco and arabidopsis leaves. The decrease in activity of cytoplasmic and vacuolar invertases in N. tabacum restricted the formation of hexoses in cells and reduced the efficiency of cold hardening in tobacco plants. More than a twofold increase in the content of soluble carbohydrates in arabidopsis was mainly caused by hexose accumulation, which was due to the increased activity of cytoplasmic and vacuolar invertases and ensured high efficiency of A. thaliana hardening to hypothermia.
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