Understanding drought responses of sugarcane cultivars controlled under low water potential conditions

Abstract

Drought resistance mechanisms of sugarcane (Saccharum officinarum L.) vary with different conditions and locations. Understanding physiological and morphological responses of sugarcane cultivars grown under uniform and controllable conditions needs to be established. Therefore, the objective of this study was to investigate the mechanisms of drought responses of sugarcane cultivars grown under low water potential conditions via polyethylene glycol (PEG) induction. The hydroponic experiment was conducted under open greenhouse conditions. A split-plot in a randomised complete block design with three replicates was used. The PEG rates (0% and 1%) were assigned as main factor. Six sugarcanes cultivars differing in drought-resistance levels were sub-plot factors. To understand drought mechanisms, physiological and morphological traits were measured during stress and recovery periods. Drought mechanisms clearly evidenced only low water potentials at early growth stages, but not terminal drought stress. The six cultivars used in this study could be classified into two groups based on responses of shoot mass after exposure to early drought, consisting of reduced shoot dry weight when exposed to early drought stress and insensitive to early drought stress. In recovery phase, shoot DM of reduced shoot dry weight cultivar ('KKU99-03') was 754.6 and 499.5 g pl-1 under control and PEG treatments, respectively, whereas shoot DM of insensitive group did not differ from control conditions. Drought resistance mechanisms, which can maintain aboveground DM of sugarcane cultivars under this condition, varied. Good adaptations for maintenance shoot mass under hydroponics were photosynthesis, stomatal conductance, partitioning of dry weight, root dry weight and green leaf number proportions. The ability to perform well with acclimation of these traits might be useful for improving drought resistance genotypes in the future.

Determination of Morpho-Physiological Traits for Assessing Drought Tolerance in Sugarcane

“…Conversely, genotypes showing earlier symptoms are considered sensitive to drought [ 7 , 21 ]. The increase in photosynthetic attributes, leaf relative water content, and green leaf area in drought-tolerant genotypes relative to drought-sensitive genotypes has been observed in sugarcane [ 14 , 32 , 33 ], switchgrass [ 34 , 35 ], wheat [ 36 , 37 ], and rice [ 38 , 39 ]. Tolerance mechanisms are favorable under mild and moderate drought conditions because they allow plants to endure stress, maintain essential functions, and sustain growth during stress [ 40 , 41 ].…”

Screening of lentil genotypes during germination and early growth stages under PEG-induced drought stress

“…In our research, it was determined that the G3664 and G3840, which were found to have high drought tolerance, were less affected by water shortage compared to the sensitive G3837 and G3759, in terms of many characteristics. In addition, Chapae et al (2020) reported that PEG-6000 can be used to form artificial drought stress to observe the response of seedlings to water scarcity and provides an alternative tool under control conditions.…”

Comparison of Physiological, Anatomical, and Morphological Traits between Sugarcane Hybrids and Their Parents with Different Stalk Dry Weights in the Early Growth Stage under Hydroponic Conditions

“…Therefore, the high stalk dry weight sugarcane cultivars under rain-fed conditions are categorized as drought-resistant cultivars [8]. Chapae et al [31] studied KK3 and UT12 under drought conditions at the early growth stage in a hydroponic system, where KK3 demonstrated good adaptation of the characteristics that promote biomass maintenance in hydroponic systems, including g s , P N , dry weight partitioning, root dry weight, and proportion of green leaves. In general, drought-resistant sugarcane cultivars conserve water in leaves by reducing water loss and maintaining water uptake in the roots [9,32,33].…”