Morpho‐anatomical traits of root and non‐enzymatic antioxidant system of leaf tissue contribute to waterlogging tolerance in Brachiaria grasses

Abstract

Soil waterlogging is a major abiotic stress that affects the growth and yield of forage grasses in the tropics. Brachiaria forage grasses are widely planted in the tropics to sustain livestock production. An outdoor study was conducted using plastic cylinders under drained and waterlogged soil conditions in order to identify root and shoot traits associated with waterlogging tolerance in Brachiaria ruziziensis (waterlogging sensitive) and Brachiaria humidicola (waterlogging tolerant). For that reason, dry mass, leaf chlorophyll content, photosynthetic efficiency, root morpho‐anatomical traits (aerenchyma, stele proportion, suberin deposition) and total non‐enzymatic antioxidant activity in leaf tissue were determined. Under waterlogging, reductions of shoot biomass, chlorophyll loss, impairment of photosynthetic efficiency and diminution of antioxidant system were found in B. ruziziensis but not in B. humidicola. In B. humidicola an increase of the antioxidant system in response to waterlogging was found. Under waterlogging, both grasses showed an increase in root aerenchyma, reduction of root stele proportion and shorter roots than plants grown under drained conditions. We conclude that a combination of greater aerenchyma formation, smaller stele proportions, increased suberin deposition in the outer part of the root and an escalation of the non‐enzymatic antioxidant system acts to enhance root aeration and prevent the deleterious effect of reactive oxygen species in plants of B. humidicola subjected to waterlogged conditions.

Comparison of growth and physiological characteristics between roughstalk bluegrass and tall fescue in response to simulated waterlogging

“…Photosynthetic light-response curves describing the photosynthetic capacity, efficiency, and other parameters are commonly used to evaluate photosynthesis performance under environmental stress [ 41 ]. Waterlogging treatments reduced chlorophyll content in some grass species [ 42 , 43 ]. Although high water potential induced stomata closure is considered to be the major reason for reduced photosynthesis during short-term flooding [ 44 ], chlorophyll content reduction may eventually result in reduced photosynthetic capacity during long-term waterlogging stress [ 43 , 45 , 46 ].…”

Morphological and Physiological Responses of Seashore Paspalum and Bermudagrass to Waterlogging Stress

“…However, photosynthesis reduction has also been found when g S does not decline during the early waterlogging periods (Ahmed et al, 2002). Many studies suggested that chlorophyll content reduction may result in reduced photosynthetic capacity during long-term waterlogging stress (Close and Davidson, 2003;Jim enez et al, 2015;Ou et al, 2011), and waterlogging treatment can affect chlorophyll content differently in grass species (Ashraf and Yasmin, 1991;Jiang and Wang, 2006). In our study, the reduced photosynthesis in bermudagrass may be associated with declines in photosynthetic pigments or reduced g S given that both were observed.…”

Divergent responses of biomass accumulation and its allocation to the altered precipitation regimes among different degraded grasslands in China

“…S3). On the one hand, anoxic conditions induced by waterlogging impaired photosynthetic e ciency and antioxidant system of plants, suppressing plant growth (Jiménez et al 2015). On the other hand, the nutrient demand was supposed to be high under soil anoxia for maintaining plant biomass (Rubio and Lavado 1999).…”