Varied patterns of sprouting and nutrient status of sugarcane sprouts in simulated and natural saline/sodic soils across two growing seasons

Abstract

Salinity/sodicity (EC/SAR) of soil arises due to combination of cations and anions, which disturbs plant metabolism. Sugarcane (Saccharum officinarum L.), ranked as a medium salt-sensitive species, is grown in Spring and Autumn seasons in the subcontinent, with differential growth behaviors in both the seasons. In this study sprouting potential, growth and tissue ionic and nutrient status in natural and simulated soil conditions were determined to compare the effects of two growing seasons and natural and simulated saline/sodic soil using salinity/sodicity tolerant (CPF-246) and sensitive (S-2003-US-778) sugarcane clones. The EC (dS/m)/SAR (sodium adsorption ratio) treatments were 4/26 and 5/30 in the selected natural field and those of 5/25 and 6/30 in the simulated soil. The data were recorded after 30 days of sowing the setts for nodal bud sprouting, length and dry mass of shoot and root, tissue ionic contents for Na+, K+, Ca2+, Mg2+, N (NO3--N), P (PO43--P) and S (SO42--S). In both the seasons, CPF-246 had greater sprouting percentage, and sprouts length and dry weights than S-2003-US-778. There was an increase in the tissue concentration of Na+ and Cl- in both the clones under either soil conditions. The EC/SAR treatments reduced the amounts of K+, Ca2+, Mg2+, N, P, S and K+/Na+ ratio both shoot and root as compared to respective controls although the reduction was greater in shoot than root. Sugarcane growing seasons had differential influence on the salinity/sodicity tolerance, since reduction in the studied parameters was greater in the autumn season. Of the two sugarcane growing media natural field conditions were more adverse than the simulated conditions. A comparison of sugarcane clones revealed that CPF-246 was more tolerant of salinity/sodicity conditions than S-2003-US-778 when grown under of the soil types and seasons. In conclusion, although natural saline/sodic fields were quite more damaging, the salinity/sodicity sensitivity in sugarcane is determined by tissue concentration of macronutrients, and the seasons have great influence on the performance of sugarcane clones.