Effect of carboxymethyl cellulose and gibberellic acid-enriched biochar on osmotic stress tolerance in cotton

Abstract

The deleterious impact of osmotic stress, induced by water deficit in arid and semi-arid regions, poses a formidable challenge to cotton production. To protect cotton farming in dry areas, it's crucial to create strong plans to increase soil water and reduce stress on plants. The carboxymethyl cellulose (CMC), gibberellic acid (GA₃) and biochar (BC) are individually found effective in mitigating osmotic stress. However, combine effect of CMC and GA₃ with biochar on drought mitigation is still not studied in depth. The present study was carried out using a combination of GA₃ and CMC with BC as amendments on cotton plants subjected to osmotic stress levels of 70 (70 OS) and 40 (40 OS). There were five treatment groups, namely: control (0% CMC-BC and 0% GA₃-BC), 0.4%CMC-BC, 0.4%GA₃-BC, 0.8%CMC-BC, and 0.8%GA₃-BC. Each treatment was replicated five times with a completely randomized design (CRD). The results revealed that 0.8 GA₃-BC led to increase in cotton shoot fresh weight (99.95%), shoot dry weight (95.70%), root fresh weight (73.13%), and root dry weight (95.74%) compared to the control group under osmotic stress. There was a significant enhancement in cotton chlorophyll a (23.77%), chlorophyll b (70.44%), and total chlorophyll (35.44%), the photosynthetic rate (90.77%), transpiration rate (174.44%), and internal CO₂ concentration (57.99%) compared to the control group under the 40 OS stress. Thus 0.8GA₃-BC can be potential amendment for reducing osmotic stress in cotton cultivation, enhancing agricultural resilience and productivity.

Keywords: Biochar; Carboxymethyl cellulose; Chlorophyll content; Osmotic stress; Reactive oxygen species.

Fig. 1

Effect of treatments on shoot fresh weight (A), shoot dry weight (B), root fresh weight (C), and root dry weight (D) of cotton cultivated under 70 OS and 40 OS stress. Bars are means of 5 replicates ± SE. Difference letters on bars showed significant changes at p ≤ 0.05: Tukey test

Fig. 2

Effect of treatments on chlorophyll a (A), chlorophyll b (B), total chlorophyll (C), and carotenoids (D) of cotton cultivated under 70 OS and 40 OS stress. Bars are means of 5 replicates ± SE. Difference letters on bars showed significant changes at p ≤ 0.05; Tukey test

Fig. 3

Effect of treatments on photosynthetic rate (A), stomatal conductance (B), intracellular CO₂ conc. (C), and transpiration rate (D) of cotton cultivated under 70 OS and 40 OS stress. Bars are means of 5 replicates ± SE. Difference letters on bars showed significant changes at p ≤ 0.05; Tukey test

Fig. 4

Effect of treatments on total protein (A), electrolyte leakage (B), total phenolics (C), and flavonoids (D) of cotton cultivated under 70 OS and 40 OS stress. Bars are means of 5 replicates ± SE. Difference letters on bars showed significant changes at p ≤ 0.05; Tukey test

Fig. 5

Effect of treatments on superoxide dismutase (SOD) (A), peroxidase (POD) (B), catalase (CAT) (C), and APX (D) of cotton cultivated under 70 OS and 40 OS stress. Bars are means of 5 replicates ± SE. Difference letters on bars showed significant changes at p ≤ 0.05; Tukey test

Fig. 6

Effect of treatments on leaf K (A), leaf Ca (B), seed K (C), and seed Ca (D) of cotton cultivated under 70 OS and 40 OS stress. Bars are means of 5 replicates ± SE. Difference letters on bars showed significant changes at p ≤ 0.05; Tukey test

Fig. 7

Cluster plot convex hull for treatments (A), osmotic stress levels (B), and hierarchical cluster plot (C) for studied attributes

Fig. 8

Pearson correlation for studied attributes