Morpho-Physiological Responses of Alamo Switchgrass During Germination and Early Seedling Stage Under Salinity or Water Stress Conditions

Abstract

Switchgrass (Panicum virgatum L.) is a warm perennial grass with valuable characteristics as a biofuel crop. To avoid competition with food crops, biofuel crops will be likely relegated to less productive soils such as marginal lands. Consequently, the salinity and water scarcity problems that commonly affect marginal lands, compromise biofuel crops germination, emergence and seedling establishment. The aims of this study were to study the germination and seedling growth of switchgrass under salinity and water stress, and to describe the morpho-anatomical responses of the roots and leaves in the seedlings to these stresses. The effect of salt and water stress was assessed using sodium chloride (NaCl) and polyethylene glycol 8000 (PEG) at the same water potentials of-0.8,-1.0 and-1.2 MPa. Seeds were moist prechilled for 7 days at 5 ºC and germinated at 30ºC/15 ºC (8 h light/16 h dark). NaCl treatments (-0.8 and-1.0 MPa) delayed germination rates but did not reduce the final germination percentage, whereas at a lower potential (-1.2 MPa) the final germination percentage was diminished. The effects of PEG (-1.0 and-1.2 MPa) on the germination rate and final percentage, were more detrimental than those induced by iso-osmotic concentrations of NaCl. PEG and NaCl reduced significantly the vigor index of-0.8 to-1.2 MPa. The morpho-anatomical changes such as the reduction in the root cross-section area and the thickening of the endodermis walls for both stress conditions and aerenchyma formation in the cortex under salinity, could significantly contribute in the survival and tolerance during the early seedling stages.

Impact of Salinity Stress on Germination of Water Spinach (Ipomoea aquatica)

“…1 containing 5 ml of deionized distilled water (for control) or 5 ml of different concentration of NaCl solutions including 25 mM, 50 mM and 75 mM. The experiment was arranged in a completely randomized design (CRD) with five replicates per treatment for three cycles [18]. The petri dishes were sealed with parafilm to avoid evaporation and the seeds were left to germinate at room temperature of 25 ± 1ºC.…”

“…Germination percentage of seeds were calculated after 10 days by using the following equation [21] GP= (Number of germinated seeds / Total number of seeds sown) x 100…”

Métodos de aplicação de peróxido de hidrogênio em mudas de gravioleira irrigadas com água salina

“…Pereira increase in relation to the seedlings under the M3 method ( Figure 2B). The limitations of leaf spraying with H 2 O 2 may be related to physical barriers, such as the epidermis and the cuticle layer, which become thicker in plants subjected to salt stress, a fact that contributed to the lower foliar absorption of H 2 O 2 (Arias et al, 2018).…”

Uncover the salt tolerance potential of accessions based on photosynthetic attributes and interaction plot in tomato (Solanum lycopersicum)

“…Surprisingly, more than 50% soils of the world in the affected areas are sodic and saline‐sodic (Beltran & Manzur, 2005; Raza et al., 2017). Furthermore, salt stress widely spreads in different parts of the world and could reveal devastating effects on all arable lands until 2050 (Arias et al., 2018; Wang et al., 2003). Though, saline conditions repress the plant growth and development due to osmotic stress, and additionally, ion toxicity also restricts the agricultural crop productivity (Ahmed et al., 2020; Alcaraz‐Meléndez et al., 2015; Munns, 2002; Wang et al., 2003).…”

“…Though, saline conditions repress the plant growth and development due to osmotic stress, and additionally, ion toxicity also restricts the agricultural crop productivity (Ahmed et al., 2020; Alcaraz‐Meléndez et al., 2015; Munns, 2002; Wang et al., 2003). Naturally, plants adapt internal mechanism to cope with environmental stresses; while, under salinity stress plant occupy various defensive mechanisms against different stresses such as hormonal alterations, antioxidants production, ion formation both physical and chemical and compartmentalization and biosynthesis of sugars, betain and glycine (Arias et al., 2018). Importantly, enhanced concentration of sodium in the soils can lead to nutritional imbalances, particularly, less potassium concentration and immediate leakage from the cells, which could manage with intrinsic survival mechanism in plants, including less Na + uptake and lower oxidative stress by increasing reactive oxygen species (ROS) detoxification (Ding et al., 2010; Siddiqui et al., 2017).…”