ABSTRACT
In the chapter, problem is considered of application of data on the content of pigments in plant leaves for (1) diagnostics of resistance to stressful abiotic factors; (2) differentiation of closely related taxonomic groups of plants on the example of two subspecies of oats: covered oats (Avena sativa subsp. sativa L.) and naked oats (Avena sativa subsp. nudisativa L.). It is shown that under influence of a stress of aluminum ions, conditions of harvesting of light energy change in high degree whereas processes of its transformation into organic substances in the reaction centers (RC) are rather protected from a stressor. At decrease in pH value of soil solution the content of chlorophyll b most decreased (by 53.22%). The total content of chlorophyll a decreased by 42.84% and depression concerned mostly light-harvesting complexes (LHCs) (52.71%), than RC of photosystems (16.98%). The depression of carotenoids’ synthesis was the least considerable—only by 19.48%. Naked samples of oats reduce content of pigments in flag leaves under stressful soil growth conditions in significantly smaller degree that does them more attractive for breeding of aluminum- and acid-resistant cultivars of this agricultural crop. The researchers conducted in 2015–2018 showed significant differences in structural and quantitative composition of a pigment machinery of flag 198leaves in naked and covered oats at flowering stage of development. Naked oats contained higher amount of pigment as a part of LHCs, and covered oats—in RC of photosystems: in LHCs—9.53 ± 0.30 and 8.44 ± 0.30 mg/g, in RC—3.57 ± 0.07 and 4.11 ± 0.10 mg/g, respectively. The average content of chlorophyll b in leaves of covered samples of oats (7.03 ± 0.25 mg/g of dry matter) was 13.1% lower, then in naked samples (7.95 ± 0.25 mg/g of dry matter). Variability of pigments’ content by years was significantly higher for group of covered samples (21.5%), than for naked one (17.9%). At naked oats chlorophyll a/b ratio was statistically significant lower, than at covered oats, respectively, 1.73 ± 0.02 and 1.92 ± 0.04. Thus, the content of photosynthetic pigments can be use as a diagnostic indicator of resistance to environmental factors (air temperature, conditions of moistening, existence of toxic ions of metals in the soil) at cultivars and breeding lines of cereal crops and as a diagnostic indicator of belonging to different genetic taxa.
