Researches
Luis Diego Fernández Araya, Juan Delgado and Andrés G. Castillo A.
Date
July, 2020
Mitigating effect of Seamaxx (Ascophyllum nodosum L.) on water stress in three varieties of coffee (Coffea arabica L.) Costa Rica 95, Obata and Catuaí Rojo.
Abiotic stress is one of the biggest restrictions and limitations for production in agriculture. The use of biostimulants
based on seaweed extracts could play a decisive strategy in stress mitigation. The objective of this work was to determine the
effect of the biostimulant Seamaxx, in the mitigation of water stress on three coffee (Coffea arabica L.) varieties: Costa Rica 95,
Obatá and Red Catuaí. The trial was carried out under greenhouse conditions at Finca Jericó, located in the coffee productive
zone of San Josecito district of San Isidro de Heredia, Costa Rica, from October to December 2019. Three treatments were
established under an unrestricted randomized experimental design with three repetitions of eight plants and each individual
plant was considered an experimental unit.
The performance of Seamaxx on the three coffee varieties was evaluated at a dose of 1lt / 200lts in each application. Two foliar applications of Seamaxx were made 7 days before stress induction (ADIE) and 14 days after stress induction (DDIE). The application on non-irrigated plants and plants in optimal water conditions was compared for each variety. The number of lost leaves at 21, 28, 35 and 36 DDIE and the percentage of defoliation (%) were evaluated. The water potential of the leaves (ΨH) was determined weekly until day 40. Three day courses were conducted at 0, 14 and 21 DDIE using the LICOR 6800. The foliar application of Seamaxx showed a retardant effect on the water stress of the treated plants that was evidenced in higher ΨH along the period of progressive water deficit that reached its maximum at 35 DDIE. Plants were rehydrated at 35 DDIE; the plants treated with Seamaxx reached the stabilization potential one day before the non treated stressed plants. On the other hand, defoliation began at 21 DDIE. The application of Seamaxx significantly decreased the progress of leaf loss during stress when compared to non treated stressed plants.
The effect of Seamaxx on the net assimilation rate of treated plants was not significant enough to assure an effect on photosynthesis under intense (<-20 bars of ΨH) water stress, eventhough in optimal water conditions an improvement on Seamaxx treated plants was observed.
The performance of Seamaxx on the three coffee varieties was evaluated at a dose of 1lt / 200lts in each application. Two foliar applications of Seamaxx were made 7 days before stress induction (ADIE) and 14 days after stress induction (DDIE). The application on non-irrigated plants and plants in optimal water conditions was compared for each variety. The number of lost leaves at 21, 28, 35 and 36 DDIE and the percentage of defoliation (%) were evaluated. The water potential of the leaves (ΨH) was determined weekly until day 40. Three day courses were conducted at 0, 14 and 21 DDIE using the LICOR 6800. The foliar application of Seamaxx showed a retardant effect on the water stress of the treated plants that was evidenced in higher ΨH along the period of progressive water deficit that reached its maximum at 35 DDIE. Plants were rehydrated at 35 DDIE; the plants treated with Seamaxx reached the stabilization potential one day before the non treated stressed plants. On the other hand, defoliation began at 21 DDIE. The application of Seamaxx significantly decreased the progress of leaf loss during stress when compared to non treated stressed plants.
The effect of Seamaxx on the net assimilation rate of treated plants was not significant enough to assure an effect on photosynthesis under intense (<-20 bars of ΨH) water stress, eventhough in optimal water conditions an improvement on Seamaxx treated plants was observed.
