Differential seedling growth and tolerance indices reflect drought tolerance in cotton

Abstract

Background Cotton production is adversely effected by drought stress. It is exposed to drought stress at various critical growth stages grown under a water scarcity environment. Roots are the sensors of plants; they detect osmotic stress under drought stress and play an important role in plant drought tolerance mechanisms. The seedling stage is very sensitive to drought stress, and it needed to explore the methods and plant characteristics that contribute to drought tolerance in cotton. Results Initially, seedlings of 18 genotypes from three Gossypium species: G. hirsutum, G. barbadense, and G. arboreum, were evaluated for various seedling traits under control (NS) and drought stress (DS). Afterward, six genotypes, including two of each species, one tolerant and one susceptible, were identified based on the cumulative drought sensitivity response index (CDSRI). Finally, growth rates (GR) were examined for shoot and root growth parameters under control and DS in experimental hydroponic conditions. A significant variation of drought stress responses was observed across tested genotypes and species. CDSRI allowed here to identify the drought-sensitive and drought-resistant cultivar of each investigated species. Association among root and shoots growth traits disclosed influential effects of enduring the growth under DS. The traits including root length, volume, and root number were the best indicators with significantly higher differential responses in the tolerant genotypes. These root growth traits, coupled with the accumulation of photosynthates and proline, were also the key indicators of the resistance to drought stress. Conclusion Tolerant genotypes have advanced growth rates and the capacity to cop with drought stress by encouraging characteristics, including root differential growth traits coupled with physiological traits such as chlorophyll and proline contents. Tolerant and elite genotypes of G. hirsutum were more tolerant of drought stress than obsolete genotypes of G. barbadense and G. arboreum. Identified genotypes have a strong genetic basis of drought tolerance, which can be used in cotton breeding programs.

Prospects Of Developing Drought Resilience In Crop Plants Through Strategic Modifications In Root System Architecture

“…Less water supply towards seed also slows down the process of hydrolyzation of stored carbohydrate reserves, which ultimately affects the transport of food to developing embryo, restricting radicle emergence from seed coat, hence reducing germination (Channaoui et al, 2019). In cotton, root morphology has been shown to play significant role in conferring tolerance to drought especially at seedling stage (Singh et al, 2018;Mahmood et al, 2022). Pace et al (1999) observed that cotton seedlings showed increased thickness and length of roots when subjected to drought stress as compared to the control seedlings.…”

“…Modification of root system has been shown to increase drought tolerance in plants (Vivek et al, 2017). Deep root systems confers high drought tolerance to plants by increasing mineral and water uptake (Mahmood et al, 2022).…”

Transcriptomic analysis reveals the beneficial effects of salt priming on enhancing defense responses in upland cotton under successive salt stress

“…Moreover, morphological attributes, including plant height (cm), stem diameter (mm) and leaf area (mm 2 ) were also recorded. The tolerance index was calculated using the methodology explained by Mahmood et al (2022). Moreover, factorial analysis of variance (ANOVA) was used to estimate the difference among genotypes, treatments, and replicates.…”

Adaptive Response and Transcriptomic Analysis of Flax (Linum usitatissimum L.) Seedlings to Salt Stress

“…Many previous studies have evaluated salt-stress adaptive changes in flax populations during germination [ 36 , 37 ]. Indicators such as germination rate, root length, and shoot length effectively reveal the behavioral adaptation of flax to salt stress during the germination period [ 38 , 39 ]. Abido et al [ 40 ] found that Egyptian flax cultivars showed wide natural variation in adaptation to salinity, and the Giza11 cultivar exhibited a higher germination rate and speed at high salinity levels compared with other cultivars.…”

“…Some flax cultivars are salt-tolerant during germination but salt-sensitive during the vegetative phase [ 42 ]. The seedling stage is an important period for crop growth and yield [ 8 , 38 ]; however, adaptive changes in flax seedlings under salt stress have been less studied. In particular, no transcriptional profiles other than Wu’s limited study [ 43 ], in which only 42.92% of RNA reads were mapped to the reference genome, have shown differentially expressed genes (DEGs) to analyze the difference in adaptability between flax cultivars under salt stress.…”