Long term salinity effect on growth, photosynthesis and osmotic characteristics in sugarcane

Abstract

The comparative responses of photosynthesis, growth, dry matter accumulation leaf water (< l ) and osmotic (S) potentials were investigated in contrasting genotypes of sugarcane. Photosynthetic rate, transpiration rate and < l did not differ significantly among genotypes in the formative stage of crop growth (60-150 days of crop age). Leaf < l showed consistent difference among the clones due to salinity treatment. During grand growth stage (150-240 days of crop age), the photosynthetic rate, transpiration rate (t) and < l decreased due to salinity treatment. Dry biomass accumulation was severely affected and biomass allocation towards stem reduced drastically in sensitive types. The reduction in ultimate sink size as revealed by cane length and stem biomass was in accordance with the tolerance potential of the clones.

Growth of sugar cane varieties under salinity

“…The different responses obtained from varieties of sugar cane regarding tolerance to salinity are related to the mechanisms developed by them to minimize the osmotic effect of salts in the soil, which limits the water absorption besides the less vulnerability to toxic concentrations of ions such as Na + and Cl - (Munns & Tester, 2008). The salt effects on the sugar cane are displayed with some restrictions in the assimilation of CO 2 (Vasantha et al, 2010), decrease in chlorophyll content (Silva et al, 2010), reduction in turgor pressure, limited elongation and cell division (Taiz & Zeiger, 2013), accumulation of compounds known as reactive oxygen species (Willadino et al, 2011) among other factors that directly reflect the depletion of plant growth.…”

Stress Physiology: Abiotic Stresses

“…Salinity induced bundle sheath leakiness to CO 2 in both clones were due to a reduction in C 3 pathway activity relative to that of the C 4 pathway (Meinzer et al 1994). A similar observation on photosynthesis, transpiration, and biomass production was also made by Vasantha et al (2010). However, Naidoo et al (2004) did not report any clear trend in carbon assimilation or gas exchange parameters despite significant reduction in biomass occurring in all salt-stressed varieties tested.…”

“…Salinity-affected sugarcane crops show a reduction in tillering, leaf number, leaf area, stem height, stem weight, and node number in all tested clones (Wahid et al 1997;Naidoo et al 2004;Vasantha et al 2010). Early work on plant crops found a 50% yield decline at 4-7 dS/m and an EC greater than 8 dS/m sometimes killed stools (Rozeff 1995;Wahid et al 1997).…”

“…Genotypic differences in salt tolerance have been established through screening responses at various levels of salinities (Wahid et al 1997;Vasantha et al 2010). In general, genotypes with EC 50 values around 15 dS/m were most tolerant across all growth stages and maintained leaf area at the highest salinity (21 dS/m) tested.…”

Salinity Stress in Arid and Semi-Arid Climates: Effects and Management in Field Crops

“…Sugarcane is a key commercial and irrigated crop of the tropical and subtropical areas of the world [99]. Sugarcane is propagated further by setts from the stem cuttings of mature plants (one-year-old crop).…”