Effects of seed priming with salicylic acid on chlorophyll a fluorescence parameters of basil (Ocimum basilicum L.) infested by field dodder (Cuscuta campestris Yunk.)

Abstract

This research was undertaken to assess the ameliorative effect of salicylic acid (0.5 mM) on photosystem II (PS II) in two basil (<em>Ocimum</em> <em>basilicum</em> L.) varieties (Iranian and Italian) infested with field dodder (<em>Cuscuta</em> <em>campestris</em> Yunk.) in the greenhouse of University of Tabriz, Iran, in 2017. The treatments were arranged as factorial using randomized complete block design with four replications. Results indicated that application of salicylic acid improved the maximum quantum efficiency of photosystem II (F_v/F_m) and performance index (PI) of basil plants infested by field dodder. The time span from F₀ to F_m (T_FM) and the energy necessary for the closure of all reaction centers (S_m) were significantly increased and the size of the plastoquinone pool (Area) declined in plants exposed to field dodder infestation. Application of salicylic acid increased the chlorophyll <em>a</em> fluorescence parameters studied in both basil varieties, especially in the Italian variety.