Growth parameters, mineral distribution, chlorophyll content, biochemical constituents and non-enzymatic antioxidant compounds of white yam (Dioscorea rotundata (L) var. gana) grown under salinity stress

Abstract

Soil salinity has a negative impact on crop production over the world. The effect of salt stress on growth, chlorophyll content, mineral distribution, biochemical constituents and non-enzymatic antioxidant compounds of white yam (Dioscorea rotundata (L) var. gana) cultivar regularly consumed in Cameroon were investigated. Plants were subjected to four different levels concentrations of NaCl (0, 50, 100 and 200 mM), with 0 mM NaCl as a control. The supply of intake doses of NaCl in the culture medium significantly (P < 0.001) decreased the dry biomass (roots and shoots), growth parameters (number of leaves, noose diameter, leaf area and stem height) and chlorophyll contents from 100 mM NaCl. Mineral elements (K, Ca and Mg) and K/Na ratio significantly (P < 0.001) decreased in roots and shoots with increasing salinity. The higher sodium (Na) concentrations were recorded in shoots than in roots. The different biochemical constituents (proline (PRO), total soluble carbohydrates (CH), soluble proteins (PR) and total free amino acids (FAA)) and non-enzymatic antioxidants compounds (total phenolic (TP) and flavonoids (FLA) contents) significantly (P < 0.001) increased from 50 mM NaCl. The main strategy in cv. gana seems to increase osmotic adjustment through high accumulation of CH, PR, FAA and PRO in the leaves and they could eventually be considered as biochemical indicators of early selection and osmotic adjustment ability for salt tolerant plants. The gana variety could be encouraged to be planted on salt affected soils for the better development in salty areas.

Growth, mineral uptake, chlorophyll content, biochemical constituents and non-enzymatic antioxidant compounds of white pepper (Piper nigrum L.) grown under saline conditions

“…The leaf area, noose diameter, the number of leaves, stem height, and dry weight were recorded for six weeks, after which, the plants were harvested. The stem height and noose diameter were determined by measuring with a ruler and vernier caliper respectively, and the number of leaves were determined by counting (Ndouma et al, 2020). Roots and shoots were dried separately at 60 °C for 72 Hours and their dry biomasses were determined.…”

“…Salinity is one of the major factors that affect plant growth and metabolism, consequently causing damage and loss of crop or yield in Littoral, semi-arid and arid zones (Taïbi et al, 2016;Hand et al, 2017;Kpinkoun et al, 2019;Kinsou et al, 2021). It is caused by saline parent bed rocks, mineral degradation, invasion of sea water in coastal regions and the over use of saline water irrigation (Ndouma et al, 2020). More than 60 million ha of irrigated land has been damaged by salt (Nouck et al, 2016).…”

“…Many authors have done works on mineral uptake by plants under salt-stress conditions (Meguekam et al, 2014;Nouck et al, 2016;Hand et al, 2017;Ndouma et al, 2020). They showed that the inhibition of potassium, calcium and magnesium by sodium is a result of K + /N + antagonism.…”

“…In response to salinity, plants produce biochemical constituents (proline (PRO), total free amino acids (FAA), soluble proteins (SP), and total soluble carbohydrates (CH)) and non-enzymatic antioxidant compounds (Total phenolic (TP) and flavonoid compounds (FLA)). Salt tolerance is determined by osmotic adjustment maintenance of ion homeostasis, the control of ion and water flux, the specific protein and free radical enzymes involved in the protection of protoplast functions (Hand et al, 2017;Ndouma et al, 2020). Numerous studies have shown that PRO acts as a mediator in osmotic adjustment stabilizing the effect of salt accumulated in the vacuole (Khalil et al, 2016).…”

“…SP needed in osmotic adjustment during salt stress are stored as nitrogen and re-used when the stress is removed (Nouck et al, 2016;Hand et al, 2017). The production and storage of FAA and CH during stress conditions is adaptive response (Ndouma et al, 2020). TP participates in the regulation of growth and development and acts as defense mechanism against biotic and abiotic stress (Chenier et al, 2013;Taïbi et al, 2016).…”