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Thirteen genotypes of sugarcane were exposed to different drought stress intensities followed by a period of stress relief. Different biomarkers were used to analyze the stress tolerance in leaves which include DPPH activity, proline, glycine betaine, lipid peroxidation and phenolic contents against different doses of Polyethylene glycol. Relatively the concentrations of all biochemical markers were increased when PEG concentration was increased. On the basis of lipid peroxidation, glycine betaine and proline contents, HSF-242, Lho-83, HSF-240, CP-77-400, CPF-198, NSG-45, NSG-60 and NSG-555 were found to be drought tolerant genotypes. In conclusion the drought stress-induced changes are reversible, at the cellular level in sugarcane.

Curcuma longa is an important dietary plant which possess several pharmacological activities, including antioxidant, antimicrobial, anti-inflamatory, anticancer and anti clotting etc. The aim of the present study was to determine the phenolic profile of Curcuma longa and in vitro antioxidant and antidiabetic activities. In HPLC chromatogram of Curcuma longa rhizome extract 15 phenolic compounds were identified namely Digalloyl-hexoside, Caffeic acid hexoside, Curdione, Coumaric, Caffeic acid, Sinapic acid, Qurecetin-3-D-galactoside, Casuarinin, Bisdemethoxycurcumin, Curcuminol, Demethoxycurcumin, and Isorhamnetin, Valoneic acid bilactone, Curcumin, Curcumin-O-glucuronide respectively. The ethanolic extract displayed an IC50 value of 37.1±0.3 µg/ml against alpha glucosidase. The IC50 value of DPPH radical scavenging activity was 27.2 ± 1.1 μg/mL. It is concluded that ethanolic extract of Curcuma long is rich source of curcumin and contain several important phenolics. The in vitro antioxidant and alpha glucosidase inhibitory effect of the plant justifies its popular use in traditional medicine.

The activity of antioxidative enzymes system is affected by salt stress, chlorophyll content (CHL), leaf relative water content (RWC), Na + and K + contents, their ratio and some oxidative stress indices were studied in leaves of ten bread wheat cultivarsSehar-06, Lu-26, NARC-09, BARC-09 and Pirsbak-09' (salt-tolerant) and Kaghan-94, Rohtas-90, Soughat-90, Shaheen-94 and Zardana-89' (salt-sensitive), grown under salinity treatments carried out in five levels (1 < dS•m −1 as control, 2, 4, 8, 16 dS•m −1) via sodium chloride. Under high salt potency significant increase for activities of antioxidant enzymes such as ascorbate peroxidase (APX) and guiacol peroxidase (GPX), occurred in salt tolerant varieties. Meanwhile, under salinity condition the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and (GPX) in sensitive cultivar were lower than control. Regarding (APX) activity there was no significant difference between salinity and control situation. Under salt stress membrane stability index (MSI) of both cultivars were negatively influenced. Hydrogen peroxide (H 2 O 2) content of salinity sensitive cultivars was higher than control. Salt tolerant varieties had more amounts of K + content, K + and Na + ratio, relative water content, yield and chlorophyll under salt conditions, and sensitive ones recorded higher Na + content at tillering stage. The mechanism of salt stress might be achieved due to low lipid peroxidation, assumingly lower changes in membrane stability index and evasion of Na + combination and amplified activity of antioxidant enzymes.

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