Differentiation of photoperiod-induced ABA and soluble sugar responses of two quinoa (Chenopodium quinoa Willd.) cultivars
Bendevis, MA and Sun, Y and Shabala, S and Rosenqvist, E and Liu, F and Jacobsen, S-E, Differentiation of photoperiod-induced ABA and soluble sugar responses of two quinoa (Chenopodium quinoa Willd.) cultivars, Journal of Plant Growth Regulation, 33, (3) pp. 562-570. ISSN 0721-7595 (2014) [Refereed Article]
Copyright 2013 Springer Science+Business Media New York
Adaptation of quinoa (Chenopodium quinoa Willd.) to new regions demands acclimation to day-length, in addition to a host of other abiotic factors. To further elucidate the effects of photoperiod on development of quinoa, two differently adapted cultivars, Achachino (short day) from Bolivia and Titicaca (day-length neutral), were subjected to continuous long (17.5 h) and short (10 h) photoperiod conditions as well as a shift between the two to trigger possible adaptive mechanisms initiated by changes in leaf soluble sugar and ABA concentration. Our findings show both cultivars responding to an increase in photoperiod with significant increases in soluble sugar concentrations and a simultaneous increase in ABA. However, Titicaca exhibited a much stronger ABA response to increase in photoperiod, whereas the increase for Achachino falls within the range of natural diurnal variation. Achachino also showed increasing sensitivity to long photoperiods throughout all reproductive growth stages, resulting in continued flowering, stem elongation and disruption of seed formation, whereas Titicaca was capable of maintaining full seed set under all the photoperiod conditions. Discernible photoperiod-dependent chlorosis of the lower leaves of Titicaca was observed under long photoperiods compared to short photoperiods, implying multi-faceted adaptive responses to changes in photoperiod which may also involve nitrogen and carbon dynamics. Both ABA and sugar signals are possibly involved in regulating the photoperiod-adaptive capability of each cultivar, leading to pronounced differences in growth and reproductive development patterns between the contrasting cultivars.