Вплив абіотичних факторів на ріст і розвиток рослин пастернаку посівного

Abstract

The main factors that have a great influence on plant growth, as well as on increasing the yield and its quality characteristics, are biotic and abiotic. Combinations of abiotic stresses, such as drought and heat, have a much greater impact on yields and product quality. The response of plants to these stresses can vary depending on the species, as well as at different stages of development. Understanding the mechanisms and how they protect plants from stress has become vital to improving the yield and quality of parsnip products in changing climatic conditions. The research aimed to study the influence of abiotic factors (temperature and precipitation) on yield, duration of phenological phases of plant growth and development, dynamics of growth of leaves and roots of parsnip in the Right Bank Forest-Steppe of Ukraine. The research was conducted in the field experiment of the Department of Vegetable Growing and Closed Soil in NL "Fruit and Vegetable Garden" NUBIP of Ukraine in the Right Bank Forest-Steppe of Ukraine during 2015-2017. The area of the accounting plot was 11.3 m2, the repetition of the experiment was 4 times. The arrangement of the research plots was systematic. As a result of research, it is established that the shortest period of sowing-seedlings lasted 16 days in the options for sowing in the 3rd decade of May and the 1st decade of June. Significant delay for 21 days of this period was observed for sowing from the 1st to the 3rd decade of April. The duration of the period from the beginning of root formation to beam ripeness was the smallest for sowing in the 1st decade of April – 28 days, and the largest for sowing in the 1st decade of June – 51 days. The vegetation period ranged from 110 to 165 days and passed for the sum of temperatures (> 10 °С) 1102.4-1439.0 °C and the sum of precipitation 128.1-225.2 mm. During sowing in April, an intensive increase in root crops from 2.9 to 3.5 g/day was observed in the second half of August. During sowing in May, the largest increase in root crops from 2.1 to 2.7 g/day was observed in the first half of September. Thus, for sowing in the 1st decade of June, this figure was highest in the second half of September (1.9 g/day). The option for sowing in the 1st decade of April provided a high yield of root crops of 50.3 t/ha, which is 5.3 t/ha or 11.8% significantly more than the control. When sowing in the following periods, a significant decrease in yield was observed compared to the control, namely: for the 3rd decade of April – by 3.5 t/ha, or 7.7%, for the 1st decade of May – by 8.8 t/ha, or 19.6%, for the 2nd decade of May – by 17.4 t/ha, or 38.6%, for the 3rd decade of May – by 23.0 t/ha, or 51.1%, for the 1st decade of June – by 31.7 t/ha, 70.6% compared to the control. There was a direct strong relationship (r = 0.74-0.99) between the growing season and yield, root weight, marketability, and biochemical parameters, namely: dry matter, dry soluble matter, sugars, vitamin C. The inverse of the strong (r = -0.98) was observed between the duration of the growing season and nitrates. Increasing the growing season by 10 days increases the yield to 6.9 t/ha, marketability up to 2.7%, root weight up to 31 g, dry matter content up to 0.7%, dry soluble matter up to 0.3%, sugars up to 0,5%, vitamin C to 0.8 mg/100 g and reduces the nitrate content to 8.4 mg/kg. Leaf area, photosynthetic potential, net photosynthesis productivity are in strong direct connection (r = 0.92-0.98) with yield. As the leaf surface area increases to 1.0 thousand m2/ha, the yield increases to 0.7 t/ha. Increasing the photosynthetic potential to 0.05 million m2 per day/ha increases the yield to 0.2-1.2 t/ha. Also, the yield increases to 0.3-0.7 t/ha by increasing the net productivity of photosynthesis to 0.05 g/m2 per day. Promising for further study is molecular knowledge of plant responses to abiotic stress, likely to pave the way for making crops resistant to climate change and increase the economic efficiency of production.