Aminoethoxyvinylglycine (AVG) ameliorates waterlogging-induced damage in cotton by inhibiting ethylene synthesis and sustaining photosynthetic capacity

In this glasshouse study, we investigated the mechanisms of aminoethoxyvinylglycine (AVG)-induced waterlogging tolerance in cotton. Two cotton cultivars Sicot 71BRF (moderately waterlogging tolerant) and LA 887 (waterlogging sensitive) were grown in a clay-loam soil, and exposed to waterlogging at early squaring stage (53 days after sowing). One day prior to waterlogging, shoots were sprayed with AVG (ReTain^®, 830 ppm). Continuous waterlogging for 2 weeks accelerated the shedding of leaves and fruits. As the duration of waterlogging increased, shoot growth rate, biomass accumulation, photosynthesis (P_n) and stomatal conductance (g_s) were all reduced. Growth of LA 887 was more severely impaired than Sicot 71BRF, with a decline in leaf P_n and g_s after just 4 h of waterlogging. Waterlogging inhibited allocation of nitrogen (N) to the youngest fully expanded leaves, photosynthesis and biomass accumulation, while it accelerated ethylene production promoting leaf and fruit abscission. AVG blocked ethylene accumulation in leaves and subsequently improved leaf growth, N acquisition and photosynthetic parameters. In addition, AVG enhanced fruit production of both cotton cultivars under waterlogged and non-waterlogged conditions. Higher ethylene production in cotton is linked with fruit abscission, implying that AVG-induced ethylene inhibition could potentially limit yield losses in waterlogged cotton.