Growth of cucumber seedlings under emulated sunlight with artificially reproduced fluctuations in photosynthetic photon flux density

Cucumber seedling growth under constant and fluctuating photosynthetic photon flux density (PPFD) light (CPL FPL, respectively) was examined to discuss whether plants can acclimate CPL versus FPL. The FPL created in a chamber by artificially reproducing fluctuations ground-level sunlight PPFD using phosphor-converted white LEDs. daily mean at the canopy surface photoperiod were same for grown two weeks, with former latter half periods either or respectively; there treatments first week four 2 × combinations last week. According analysis week, net assimilation rate (NAR) tended be lower than CPL, while leaf area ratio specific (SLA) greater CPL. NAR may due delayed response of photosynthesis increase, i.e., induction, non-linearity PPFD-response curve rate. SLA consistent previous reports, although mechanism underlying unclear. For no significant difference those parameters among treatments, possibly because change structure accompanying self mutual shading. relative shoot dry mass also not significantly different treatments. Thus, cucumber seedlings initially showed physiological morphological responses distinctively, did improve continued respective conditions necessarily acclimative whole-plant level.