Causes of Growth Reduction in Elongating and Expanding Leaf Tissue of Sugarcane Under Saline Conditions

Abstract

Plants of sugarcane, cv. Co 1148, were subjected to salinisation with 200 milliequivalents L-1 of Cl- -type salts mixture (having Na+, Ca2+ and Mg2+ as 3 :1:1 and Cl- and SO42- as 4:1 on a milli- equivalent basis) for two weeks or more during the tillering phase. Soluble sugar concentrations increased by 55% in the blades of recently matured leaves (source tissues) and by nearly 225% in the elongating sheath bases (sink tissues) as a result of salinisation. Leaf elongation within 3 h of desalin- isation was much faster than for the non-saline controls. The accumulated sugars also dropped in the rapidly elongating sheath bases by 43% during this period after desalinisation. Further, the drop in sugar levels upon desalinisation was of greater magnitude in the more rapidly growing sheath bases. The present studies indicate that even though the supply of carbohydrates from the source tissues is reduced, the sink tissues are not able to make use of these sugars under saline conditions. As Na+ and Cl- concentrations did not change within 3 h of desalinisation, the ions themselves did not appear to affect metabolic activities of the sink tissues; this suggestion is further supported by the utilisation of accumulated sugars within 3 h of desalinisation.

Effects of NaCl and iso-osmotic PEG stress on growth, osmolytes accumulation and antioxidant defense in cultured sugarcane cells

“…In vitro culture technique provides a controlled and uniform environment for studying the physiological effects of salt and dehydration stress at the cellular (Ahmad et al 2007) as well as plant level (Lokhande et al 2011). Therefore, besides understanding the effects of salt and dehydration stress at the whole plant level ex vitro (Kumar et al 1994;Wahid et al 1997;Wahid 2004;Patade et al 2011), attempts are being made to study the in vitro cellular or tissue levels stress responses (Cui et al 2010;Lokhande et al 2010;Pan et al 2010;Sun et al 2010). Studies with non-halophytes have shown that degree of salt tolerance observed in the whole plant is also exhibited in callus tissues suggesting that salt tolerance mechanisms also operate at cellular level (Arzani 2008;Xu et al 2011).…”

Salt and drought tolerance of sugarcane under iso-osmotic salt and water stress: growth, osmolytes accumulation, and antioxidant defense

“…Sugarcane is a glycophyte; reported to be salt sensitive; and exhibits toxicity symptoms, low sprout emergence, nutritional imbalance, and overall growth reduction leading to low biomass (Wahid 2004). Salinity effects on sugarcane have been studied at the physiological level (Kumar et al 1994;Wahid et al 1997;Wahid 2004;Patade et al 2008). Errabii et al (2007) has analyzed effects of salt and mannitol stress on sugarcane calli in relation to growth, ions, and proline concentrations.…”

Stress Physiology: Abiotic Stresses

“…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. Salt stress reportedly increased soluble sugars in the leaf sheaths of sugarcane, possibly due to reduced sink strength (Kumar et al 1994).…”