Drought tolerance of passion fruit plants assessed by the OJIP chlorophyll a fluorescence transient

Chlorophyll a fluorescence of two passion fruit cultivars grown in a greenhouse were evaluated to determine the effect of induced water stress and recovery on young plants. One month-old passion (Passiflora edulis Sims) cv. Yellow Master (FB200) and Maguary (FB300) plants were evaluated in 11.0 L pots after 11 days of water withholding, imposed by suspension of irrigation, and after six days of rewatering. Drought treatment increased all points of the OJIP curves in FB200 plants. With water stress, reductions of Delta V-OP occurred in FB300 only in J-I phase, while all phases from OJIP curve were reduced in FB200. J-I phase showed signals of recovery within six days in FB200 but this period of rewatering was not sufficient for recovery of O-J and I-P phases. There was total recovery of Delta V-OP, values in FB300 followed by an increment of efficiency which an electron is transfer to photosystem I (PSI) acceptor side, evidenced by a positive increase of I-P phase after stress. To FB200, L and K-band increased after five days of water stress with partial recovery after one week rewatering. But, to FB300, significant difference of bands was only observed at 11 days from water withholding and the difference between water treatments was very evident, with total recovery after rewatering. On the day of maximum stress, the maximum efficiency of PSII (F-v/F-m ratio) decreased significantly in both passion cultivars while the effective antenna size of an active reaction center (ABS/RC) values increased 24 and 11% in FB200 and FB300, respectively. With rewatering of plants, declines of F-v/F-m values persisted by at least three days in FB200 passion cultivar. Also, increases of ABS/RC in FB200 (+110%) was irreversible and persisted until the six day after rewatering. These findings showed that two passion cultivars differed in the plasticity of their response to drought and rewatering and further shows that under drought conditions the FB300 plants possess an advantage over FB200 plants in terms of stability and efficiency in utilizing energy. Measurements of OJJIP fluorescence transients, F-v/F-m and ABS/RC ratios, analyzed using the JIP-test, were good tools for the screening of the potential to cope with and to recover from drought. (c) 2012 Elsevier B.V. All rights reserved.