Abstract
Improving nitrogen use efficiency is a significant scientific problem to be solved. Two maize hybrids JD27 (Jidan 27) and SD19 (Sidan 19) were selected to study the effects of nitrogen levels on root characteristic parameters and plant dry matter accumulation, distribution and transportation. We set five different nitrogen levels, which were nitrogen deficiency (000N), low nitrogen (075N), medium nitrogen (150N), high nitrogen (225N) and excessive nitrogen (300N). The results showed that the root length and root surface area of JD27 were significantly higher than those of SD19 under 075N. With the increase of nitrogen levels, the root difference among varieties gradually decreased. The root length, projection area, total surface area and total volume reached the maximum values at silking stage. The average root diameter kept stable or decreased slowly with the growth stage. The dry matter accumulation of JD27 was higher than that of SD19 at all growth stages. Increasing the amount of nitrogen fertilizer can promote the transport of dry matter to grain and improve dry matter transport efficiency after anthesis. Under the treatment of medium and high nitrogen fertilizer, maize was easy to obtain a higher yield, but excessive nitrogen fertilizer inhibited the increase of yield. This study provides theoretical and practical guidance for maize production techniques.
Highlights
Accepted: 29 March 2021Nitrogen is an essential factor affecting plant growth and development, yield and quality, and plays an important role in plant life’s physiological regulation [1]
In V13 stage, there was no significant difference in root volume between Jidan 27 (JD27) and Sidan 19 (SD19) under nitrogen levels
The results showed that SD19 was superior to JD27 in average root diameter under high nitrogen condition, and the increase or decrease of nitrogen levels had little effect on the average root diameter of JD27 (Table 3)
Summary
Accepted: 29 March 2021Nitrogen is an essential factor affecting plant growth and development, yield and quality, and plays an important role in plant life’s physiological regulation [1]. Nitrogen fertilizer is the most widely used in maize production [2,3]. Maize nitrogen use efficiency is a quantitative trait controlled by multiple genes, so it must be expressed through a series of morphological, physiological and biochemical characteristics [6,7]. Root growth is closely related to physiological metabolism and dry matter accumulation of shoots [8,9]. The difference of nitrate utilization ability of maize varieties depends on the amount of nitrogen absorbed by aboveground parts, and depends on the root growth [11,12]. The root morphology, distribution and physiological and biochemical characteristics have significant effects on nitrogen absorption. The difference in nitrogen use efficiency was mainly related to nitrogen absorption and dry matter production.
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