Plants experience a number of limiting factors, as drought and heat, which are often coinciding stress factors in natural environment. This study evaluated the changes in mesophyll cell ultrastructure in the leaves of two varieties of winter wheat (Triticum aestivum L.), differing in their drought tolerance, under individual or combined drought and heat treatment. Although the individual stress factors affected leaf ultrastructure, the damaging effect of the combined drought and heat was more pronounced and manifested certain differences between genotypes. Chloroplasts and mitochondria were affected in a variety-specific manner under all adverse treatments. The organelles of the drought-tolerant Katya were better preserved than those in the sensitive variety Sadovo. Leaf ultrastructure can be considered as one of the important characteristics in the evaluation of the drought susceptibility of different wheat varieties.

No abstract

Досліджено вплив короткотривалих температурних стресів на активність ліпоксигенази, вміст фотосинтетичних пігментів і ультраструктурну будову клітин мезофілу листків жаростійкого сорту Triticum aestivum L. Ятрань 60. Встановлено, що в проростках міститься три ізоформи 9-ліпоксигенази. Виявлені специфічні зміни у складі фотосинтетичних пігментів. Встановлено збільшення кількості пластоглобул у стромі хлоропластів після дії низької позитивної температури і відсутність таких змін після теплового стресу Ключові слова: Triticum aestivum L., ліпоксигеназа, пігменти, ультраструктура, температурний стрес The effect of short-term temperature stresses on the activity of lipoxygenase, content of photosynthetic pigments and ultrastructure composition of mesophyll cells of leaves heat-resistant cv. Triticum aestivum L. Yatran 60 has been investigated. It is determined that three isoforms of 9-lipoxygenase is found in seedlings. Specific changes in the photosynthetic pigments were revealed. The increase in the number of globular inclusions in chloroplast stroma after exposure to low positive temperatures and the lack of change after heat stress were found