Morphophysiology and production of guava as a function of water salinity and salicylic acid¹

Morfofisiologia e produção de goiabeira em função de salinidade da água e ácido salicílico

HIGHLIGHTS:

Salt stress reduces the CO₂ assimilation rate by the action of stomatal and non-stomatal factors.

The electrical conductivity of 3.2 dS m^-1 is harmful for the cultivation of grafted guava.

Salicylic acid up to 3.6 mM does not alleviate salt stress in grafted guava at 390 days after transplanting.

ABSTRACT

The availability of water with low electrical conductivity for irrigation in the Northeastern semi-arid region is one of the limiting factors for the expansion of irrigated agriculture. Thus, it is necessary to use waters with high electrical conductivity, requiring the search for strategies to reduce the negative impacts of salts on plants. In this context, the objective of this study was to evaluate the morphophysiology and production of guava cv. Paluma subjected to irrigation with saline waters and foliar application of salicylic acid after grafting. The experiment was conducted under greenhouse conditions in Campina Grande - PB, Brazil, in a randomized block design, adopting a 2 × 4 factorial scheme, with two values of electrical conductivity of irrigation water - ECw (0.6 and 3.2 dS m^-1) and four concentrations of salicylic acid (0, 1.2, 2.4 and 3.6 mM), with three replicates. Irrigation with water of 3.2 dS m^-1 reduced gas exchange, rootstock and scion diameters, crown diameter and volume, vegetative vigor index, polar and equatorial diameters of fruit, number of fruits, mean fruit weight, and fresh fruit weight of fruits of guava cv. Paluma. Salicylic acid application up to 3.6 mM did not mitigate the effects of salt stress on grafted guava cv. Paluma, at 390 days after transplanting.

Key words:
Psidium guajava L.; semi-arid region; salt stress