Morphological features of oat (Avena Sativa L.) shoots formation in the southern part of Ukraine

Abstract

Oats is essential for agricultural production and processing industry due to the unique biochemical composition of its grain. Thus, it is very important to study the biological and morphometric features of oats. The length and area of the plant's organs can establish a degree of comfort of growing conditions and determine during which period of plant's life the external weather conditions changed. Phytomers are basic repetitive functional units of the oat shoot. This paper presents the description and parameters of development of oat shoot metamers, namely, the identification of growth patterns of terrestrial vegetative metamers of oat shoots and their parts. The experiments were conducted in 2013, 2014 and 2018. The weather conditions of the specified years varied greatly – 2013 and 2014 were the most favorable in terms of humidification and precipitation, while 2018 was a very dry one. The paper determines the absolute and relative growth rates of the oat shoot internode paper and the maximum growth rate of each metamer in the linear phase. According to our observations, the absolute growth rate of oats was negligible and increased from 0.01 to 0.5 mm/d when the air temperature varied from 15 °C to 20 °C. However, when the air temperature reached about 20 °C, the absolute growth rate increased from 0.5 mm/d to almost 2 mm/d. We also found the effective sum temperatures under which the beginning and the end of the growth of each internodes take place. Thus, the first internode starts to grow the effective temperature sum of up to 117 °C is with the accumulated while the panicle starts growing when the effective temperature sum of up to 668 °C is accumulated. The growth of both the seventh internode and the panicle stops at the same time when the effective temperature sum of up to 1173 °C is accumulated. The ontogeny of oat shoots has a regular sequence of growth and development of terrestrial vegetative shoot metamers and their parts. The average growth duration of oat stem internode duting the years of research constituted 9 days for the first internode, 30 days for the seventh internode and 26 days for the panicle .