Leaf nitrogen metabolism during reproductive phase is crucial for sustaining lint yield of densely populated cotton genotypes

Abstract

Planting density and genotype choice are important agronomic techniques to achieve high crop yields. This study explored how planting density and genotypes affect cotton (Gossypium hirsutum L.) leaf N metabolism and lint yield. Treatments included three planting densities (low, 3.00 × 10 4 ; moderate, 6.00 × 10 4 ; and high, 9.00 × 10 4 plants ha −1) and two genotypes (Zhongmiang16 and J-4B). A randomized complete block design with split plot arrangement was used. Planting density of 6.00 × 10 4 ha −1 positively influenced leaf physiobiochemical attributes and boll production. The high planting density reduced lint yield by suppressing leaf soluble sugar, protein, amino acid, chlorophyll a, chlorophyll b, nitrate N and nitrite N content, nitrite reductase, and nitrate reductase activity. Moderate-density crop produced 15.9 and 10.7% more lint yield than low-and high-density planting, respectively. This high yield was the result of improved leaf level functioning (e.g., increased pigmentation and N metabolism during late reproductive growth), which increased C assimilation. Favorable leaf microclimate could also have sustained activities of leaf nitrate and nitrite reductase and increased amino acid and protein contents, with better distribution of N metabolic assimilates. Late reproductive structure development closely allied with leaf physiological attributes under a short growing season. Cotton genotypes, irrespective of their architectural variation, produced higher lint yield when grown at 6 × 10 4 ha −1 in a short cropping season. 1 INTRODUCTION Cotton (Gossypium hirsutum L.) is the leading natural fiber producing plant worldwide (Constable & Bange, 2015). China is among the top cotton-producing countries of

Optimized Nitrogen Topdressing Strategies Enhance Steviol Glycoside Productivity in Stevia (Stevia rebaudiana Bertoni) Plants

“…These results reflect the differences in N functions for SG production at different growth stages. Thus, the accumulated N during the early growth stage is mainly functioned in plant growth and biomass formation, while the N after the vegetative growth stage should consider the leaf secondary metabolism (Khan et al 2020;Zhou et al 2019b). Collectively, as plant growth processes, the contribution of stevia biomass to TSG yield decreases, which is the opposite trend as the contribution of SG concentrations.…”

Effect of intermittent shade on nitrogen dynamics assessed by 15N trace isotopes, enzymatic activity and yield of Brassica napus L.

“…15 Naccumulationofplantorgan = drymatterweight  Nconcentration  15 Nenrichment 2.3.4 Assay of NR, NiR, GS and GOGAT activities Samples of fresh leaves and pods were collected in liquid nitrogen at 10-day intervals following shading to assess enzyme activity. According to previously described procedures, the enzymes nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamate synthase (GOGAT) were examined (LIANG et al, 2011;Majlath et al, 2016;Khan et al, 2020).…”