Nitrogen modulates cotton root morphology by affecting abscisic acid (ABA) and salicylic acid (SA) content

Abstract

A hydroponic experiment was conducted to explore the effects of nitrogen on cotton root morphology and related hormone contents and to analyse the correlation between the indexes. The effects of different nitrogen concentrations (N0, N1, N2, and N3 with 0, 2, 4, and 8 mmol l −1 , respectively) on main and lateral roots were evaluated. A moderate nitrogen concentration (N2, 4 mmol l −1) promotes root growth. Lateral roots responded quickly to changes in nitrogen concentrations. Compared with N0 treatment, N2 treatment resulted in significantly greater main root volume after 12 days as well as increased lateral root length, root projected area, root surface area, and root volume after 8 days. Nitrogen significantly decreased abscisic acid (ABA), salicylic acid (SA), and isopentenyladenine (iP) content, which were the lowest in N2 treatment (33.92% lower than N0). The ABA and SA content were negatively correlated with root morphology. This shows that a moderate nitrogen concentration (4 mmol l −1) significantly decreased ABA and SA content in the main and lateral roots and promoted root growth in cotton plants. These results will contribute to root growth theory regarding efficient nitrogen utilization by cotton plants and will provide a theoretical basis to ensure nitrogen resources are utilized efficiently.

Root Reduction Caused Directly or Indirectly by High Application of Nitrogen Fertilizer Was the Main Cause of the Decline in Biomass and Nitrogen Accumulation in Citrus Seedlings

“…Meanwhile, the root length, root surface area, root volume, root-crown ratio, and biomass of all organs, total N concentrations, and N accumulations of citrus seedlings showed a tendency to first increase and then decrease with the increase of N rates. These were in agreement with the results of previous studies on spruce [55], cotton [56], and passion fruit [57]. The idea was further supported that the root dry weight, root length, and root surface area of rice were increased with an increase of N within a certain range of N applications [58].…”

Enhancement of Wheat Seed Germination, Seedling Growth and Nutritional Properties of Wheat Plantlet Juice by Plasma Activated Water

“…Previous studies showed that H 2 O 2 could diffuse through the plant cell membrane and act as a signalling molecule mediating in the early growth during imbibition and germination (Ranieri et al 2020 ), yet the positive effects of PAW in the current study could not be associated with it. In PAWs, NO 3 − and NO 2 − could serve as the source of N and be metabolized by wheat seed, which was the key effector, on the other hand, they could be reduced to NO, which modulated various hormones controlling seed dormancy and germination such as abscisic acid, gibberellins and indoleacetic acid (Chen et al 2020 ; Mu et al 2018 ). And the content of plant nitrogen was closely related to photosynthesis and further affected the accumulation of dry matter in crops (Verkroost and Wassen 2005 ), which explained why wheat seeds exhibited higher mean dry weight and seed vigour when irrigated with PAWs as reported in the current study.…”

Insights on Phytohormonal Crosstalk in Plant Response to Nitrogen Stress: A Focus on Plant Root Growth and Development

“…At the same time, it has been found that several plant species link ABA levels with nitrogen status. Although there is considerable evidence of a correlation between ABA levels and nitrogen status in several plant species, the relationship between both is not generally consistent [ 30 , 65 , 82 , 83 , 84 , 85 ]. For instance, there is no statistically significant difference in ABA levels of A. thaliana between high-nitrogen (HN) and low-nitrogen (LN) seedlings [ 86 , 87 ].…”