Physiological and Biochemical Responses of Sugarcane Varieties to Salt Stress

Abstract

Salt stress is one of the most limiting environmental factors for agricultural yields in the Semiarid region of Brazil. Considering the expansion of areas with sugarcane crops in this region, the selection of more adapted plant varieties to this environment is an essential tool for the sustainability of this activity. Thus, the objective of the present work was to evaluate the physiological and biochemical responses of plants of ten sugarcane varieties to salt stress. The experiment was conducted in a greenhouse using a randomized block design, in a 6×10 factorial arrangement consisting of six salinity levels in the irrigation water (0, 1.0, 2.0, 4.0, 6.0, and 8.0 dS m-1) and ten sugarcane varieties (VAT 90212, RB 72454, RB 867515, Q 124, RB 961003, RB 957508, SP 791011, RB 835089, RB 92579, and SP 943206), with three replications. Salt waters were applied every two days to increase the soil moisture to field capacity and promote leaching. The gas exchange, chlorophyll content, and total soluble and reducing sugars of leaves were evaluated at 90 days after planting. The highest chlorophyll contents were found in plants of the varieties Q 124, RB 96103, RB 835089, and SP 943206. The effect of salinity on the sugarcane plants affected their leaf gas exchanges and total soluble and reducing sugar contents, denoting the adaptability of plants to the stress conditions evaluated. The decrease of stomatal conductance resulted in decreases in photosynthetic rates in plants of all sugarcane varieties evaluated, except for RB 867515.

Characterization and gas exchange in accessions of Saccharum complex under salinity in the Sub-middle São Francisco, Brazil

“…The results are similar to those found by Simões et al (2019), who studied sugarcane varieties subjected to different values of water electrical conductivity and observed that the variety RB 867515 maintains the same photosynthetic rate with increasing salinity, despite showing a reduction in its stomatal conductance, demonstrating relative tolerance to salinity. Nonetheless, Lira et al (2018) in a study with the cultivar RB 867515, concluded that the increase in irrigation water salinity inhibited the stomatal conductance and photosynthetic capacity of the plants.…”

“…According to Simões et al (2019), soil salinization significantly affects the gas exchange of sugarcane varieties and its detailed evaluation can demonstrate their adaptability to the stress conditions imposed. In addition, Taiz et al (2017) report that higher rates of stomatal conductance, transpiration and photosynthesis lead to significant increase in crop production.…”

“…The effect of salinization on plants is an extremely complex phenomenon that involves morphological (Targino et al, 2017;Braz et al, 2019), physiological (Lira et al, 2018) and biochemical (Simões et al, 2019) changes caused by low water availability to plants and by the toxicity of specific ions, reducing growth, development and yield of the crop.…”

Physiological changes and growth of soursop plants under irrigation with saline water and H2O2 in post-grafting phase

“…There is a directly proportional relationship between stomatal conductance (gs) and transpiration (E) so that the reduction of stomatal conductance contributes to the reduction of transpiration since the stomata are a gateway for gas and water exchange in plants and exert a strong influence on the characteristics associated with photosynthesis and transpiration (Yuping, Hongbin, Yuanyuan, & Suiqi, 2017). Simões, Coelho, Mesquita, Calgaro and Silva (2020), when evaluating the physiological and biochemical responses of sugarcane varieties to salt stress, observed a reduction in the transpiration rate of plants with the increase in salinity, and highlighted that such a reduction is a strategy of the plant to reduce water loss through transpiration, constituting a resistance mechanism to salt stress. According to the means comparison test ( Figure 1C), it was observed that transpiration of soursop leaves was superior in plants subjected to spraying with 20 µM H 2 O 2 (1.93 mmol H 2 O m -2 s -1 ) compared to the control treatment (0 µM) (1.45 mmol H 2 O m -2 s -1 ).…”

Impact on Proline Content of Sugarcane (Saccharum officinarum L.) under Salinity Stress

“…Salinity affect crop productivity by disturbing the plant basic phenomenon of growth and development like germination, vegetative and reproductive stages (Basalah, 2010and Grewal, 2010, Granja et al, 2018. Salinity causes physical drought in soil and hinders the water uptake of plant leads to ionic toxicity, osmotic stress and nutrient (Shrivastava and Kumar, 2015).Basic problem behind salinity is, it decreases the soil osmotic potential by which sodium and chloride toxicity increases and water availability to plants decreases (Taiz et al, 2017;Simões et al, 2019). Several studies show that proline biosynthesis gene is induced on salinity stress that leads to its accumulation in plant (Simões et al, 2019), also it rapidly accumulates in plants subjected to water or osmotic stress and cold stress (Verslues et al, 2006).…”