Influence of light quality on fluctuating asymmetry of bilateral traits of forced parsley leaves
2017
Rakutko, S., Institute for Engineering and Environmental Problems in Agricultural Production - IEEP, Tyarlevo, Pushkinsky distr., St. Petersburg (Russian Federation) | Rakutko, E., Institute for Engineering and Environmental Problems in Agricultural Production - IEEP, Tyarlevo, Pushkinsky distr., St. Petersburg (Russian Federation) | Kaposhko, D., Saint-Petersburg State Agrarian Univ. (Russian Federation) | Vaskin, A., Saint-Petersburg State Agrarian Univ. (Russian Federation) | Tranchuk, A., Riga Technical Univ. (Latvia)
Under the influence of radiation energy the plants feature a number of physical effects, which lead to regulatory and other processes, up to gene expression. Single photons of irradiation absorbed by plant organisms initiate quick and visible transformation of the morphological and physiological state of plants. The most striking manifestation of developmental stability of a biological object at macro level is fluctuating asymmetry, which involves slight and random deviations in bilateral (mirror) traits. The fluctuating asymmetry is known to be minimal only under optimal environmental conditions but it increases under any stress conditions. If non-optimal irradiation parameters, affecting the plants, are considered a stress factor, the fluctuating asymmetry level may be taken as an indicator of the plant status for assessment of effectiveness and sustainability of the plant growing process under artificial conditions. We conducted several studies to identify the relationship between the level of fluctuating asymmetry of forcing parsley leaves (Petroselinum crispum var. tuberosum) and the light quality of different radiation sources. Two sources with equal photosynthetic photon flux density of 80 µmol.m -2.s -1 in the growing zone were used: a LED irradiator, with the ratio of radiation density (blue kB 400-500 nm, green kG 500-600 nm and red kR 600-700 nm) being kB : kG : kR = 31 % : 9 % : 60 %, and high pressure sodium lamps with the ratio of kB : kG : kR = 9 % : 54 % : 37 %. The length of the first leafstalks of the first order extending from the rachis was considered as a bilateral trait. The size-dependence of this trait was not found. Statistical analysis of the (L-R) variant distribution by the Wilcoxon test showed the fluctuating type of asymmetry. The effect of irradiation light quality on the leaf fluctuating asymmetry level was revealed. The higher fluctuating asymmetry level was found to correspond to smaller values of parsley productivity.
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