Antioxidant responses to water deficit by drought‐tolerant and ‐sensitive sugarcane varieties

Abstract

Water deficit is the major yield‐limiting factor of crop plants. The exposure of plants to this abiotic stress can result in oxidative damage due to the overproduction of reactive oxygen species. The aim of this work was to study the antioxidant‐stress response of drought‐tolerant (SP83‐2847 and SP83‐5073) and drought‐sensitive (SP90‐3414 and SP90‐1638) sugarcane varieties to water‐deficit stress, which was imposed by withholding irrigation for 3, 10 and 20 days. The drought‐sensitive varieties exhibited the lowest leaf relative water content and highest lipid peroxidation, hydrogen peroxide (H2O2) and proline contents during the progression of the drought‐stress condition. The antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPOX) and glutathione reductase (GR) activities changed according to variety and stress intensity. SP83‐2847 exhibited higher CAT and APX activities than the other varieties in the early stage of drought, while the activities of GPOX and GR were the highest in the other varieties at the end of the drought‐stress period. A Cu/Zn SOD isoenzyme was absent at the end of drought period from the SP90‐3414‐sensitive variety. The results indicate that lipid peroxidation and early accumulation of proline may be good biochemical markers of drought sensitivity in sugarcane.

Multiple stresses on the oxidative metabolism of sugarcane varieties

“…Similar results have been associated with tolerance to water deficiency in wheat (SAIRAM et al, 1998) and to salinity in sugarcane (WILLADINO et al, 2011). Increase or maintenance of APX and CAT activities indicates the importance of these enzymes in H 2 O 2 detoxification and protection against oxidative damage (CIA et al, 2012).…”

“…In the triple stress combination, an increase in MDA content was observed in RB98710. Low MDA levels are representative of tolerance in sugarcane genotypes exposed to water deficiency (CIA et al, 2012).…”

Automatically controlled deficit irrigation of lettuce in “organic potponics”

“…Relative water content (RWC) was analyzed on the 31 st DAT at 12h00, following the methodology of Cia et al (2012). One foliar segment (2 cm length × 2 cm width) was collected from the middle portion of young fully expanded leaves from each plot, properly stored in plastic bags and cooled to avoid tissue dehydration until analysis in the laboratory.…”

“…The economy in water and nutrients for plant cultivation will depend on the efficiency of the sensorbased controllers for irrigation to avoid either drainage or drought, which causes waste of water or growth limitation, respectively (Cia et al, 2012;Boaretto et al, 2014;Medici et al, 2014). The lack of such controllers at a low cost and ready to be used in commercial conditions may explain why precise irrigation is rarely used for growing plants in pots, as most use timers or manual control (Montesano et al, 2016).…”

Enzymatic activity of three sugarcane varieties under salt stress

“…These data corroborate those observed by Willadino et al (2011), who evaluated the salt stress on the variety RB861515 and observed a more efficient mechanism in the protection of the plant against the action of reactive oxygen species, particularly H 2 O 2 , due to the increase in the activities of the enzymes CAT and APX. The increase in APX and CAT activity indicates the importance of these enzymes in the detoxification of H 2 O 2 and protection against oxidative damages (Cia et al, 2012). Morais (2013), studying the combined action of abiotic stress factors, reported that the enzymatic behavior of the variety RB867515 was efficient in the regulation and detoxification of the ROS produced in the plant cell, indicating a greater tolerance of this variety to the different types of stress.…”