Differential Responses of Polyamines and Antioxidants to Drought in a Centipedegrass Mutant in Comparison to Its Wild Type Plants

Abstract

Centipedegrass (Eremochloa ophiuroides [Munro] Hack.) is an important warm-season turfgrass species with low turf maintenance requirements. However, our knowledge on physiological adaptation of centipedegrass to drought stress is limited. Physiological responses to drought in a gamma-ray-induced mutant 22-1 as compared with two wild type (WT) lines were analyzed for understanding of drought tolerance mechanism of centipedegrass. The mutant showed an elevated drought tolerance with higher levels of relative water content, net photosynthetic rate (A) and stomatal conductance (gs) and lower levels of ion leakage and malondialdehyde (MDA) under drought stress as compared with WT plants. A showed significant correlation with gs and MDA. Higher levels of antioxidant enzymes activities, non-enzyme antioxidants, and polyamines including putrescine (Put), spermidine (Spd), and spermine (Spm) were maintained in 22-1 than in WT plants. Superoxide dismutase (SOD), catalase (CAT), ascorbate-peroxidase (APX), and glutathione reductase (GR) activities and ascorbic acid (AsA) content were significantly correlated with both Put and Spd levels, and reduced glutathione level was correlated with Put during drought stress. Exogenous application of Put, Spd, and Spm increased drought tolerance and activities of SOD, CAT, APX, and GR in WT plants. The results suggest that higher levels of polyamines and antioxidant defense system are associated with the elevated drought tolerance in 22-1, which may improve protection on photosynthesis against drought induced oxidative damage.

Root‐tip cutting and uniconazole treatment improve the colonization rate of Tuber indicum on Pinus armandii seedlings in the greenhouse

“…However, the significant decrease in plant height, biomass, root weight and root activity of root tip‐cut P. armandii seedlings colonized by T. indicum raises concerns about its further application in truffle cultivation. The activities of SOD and POD are considered to be important indicators for stress resistance in plants (Liu et al , ; Tanveer and Shah, ), and in this study, these antioxidant enzymes were significantly reduced by root‐tip cutting. However, the combined treatment of 5 mg l −1 uniconazole and root‐tip cutting presents an alternative approach for mycorrhizal synthesis and was associated with relatively high colonization rates, biomass, plant height, root–shoot ratio, root weight and stem circumference of P. armandii seedlings.…”

Cholesterol accumulation by suppression of SMT1 leads to dwarfism and improved drought tolerance in herbaceous plants

“…It has been known that polyamines are involved in plant adaptation to abiotic stress. For example, Put, Spd, and Spm accumulated in centipedegrass ( Eremochloa ophiuroides ) in response to drought, with higher levels in drought‐tolerant mutant than in the WT (Liu, Chen, Guo, & Lu, ). Exogenous application of Put, Spd, or Spm increased drought tolerance in bermudagrass (Shi et al, ) and centipedegrass (Liu et al, ).…”

“…For example, Put, Spd, and Spm accumulated in centipedegrass ( Eremochloa ophiuroides ) in response to drought, with higher levels in drought‐tolerant mutant than in the WT (Liu, Chen, Guo, & Lu, ). Exogenous application of Put, Spd, or Spm increased drought tolerance in bermudagrass (Shi et al, ) and centipedegrass (Liu et al, ). Overexpression of SAMDC resulted in elevated levels of Put, Spd, and Spm and enhanced tolerance to abiotic stresses in transgenic tobacco plants (Waie & Rajam, ).…”

“…centipedegrass (Liu et al, 2017). Overexpression of SAMDC resulted in elevated levels of Put, Spd, and Spm and enhanced tolerance to abiotic stresses in transgenic tobacco plants (Waie & Rajam, 2003).…”

“…It has been known that polyamines are involved in plant adaptation to higher levels in drought-tolerant mutant than in the WT (Liu, Chen, Guo, & Lu, 2017). Exogenous application of Put, Spd, or Spm increased drought tolerance in bermudagrass (Shi et al, 2010) and…”