Maize leaf functional responses to drought episode and rewatering

10 Effects of crop growth and physiological activity to drought and irrigation regimes 11 have been extensively studied; however, the responses of plant growth, morphological 12 and photosynthetic behaviors to drought episodes and thereafter rewatering receive a 13 less attention. This field experiment was carried out directly in situ at an agricultural 14 ecosystem research station during 2015-2016, in a northeastern China, on the 15 renowned northeastern maize production belt, where is being threatened by severe 16 drought. A field automatic rain-shelter was used, and five irrigation regimes including 17 control, four drought episodes, and rewatering treatments were established. The 18 chlorophyll contents (SPAD values), light-saturated photosynthetic rate (Asat), and 19 photosystem II actual quantum yield (ΦPSII), maximum quantum yield (Fv′/Fm′) 20 decreased at lower leaf positions and with plant development. Episodic drought 21 effects on plant growth, leaf morphological traits and photosynthetic processes at both 22 vegetative and reproductive stages were severely remarked, particularly at late 23 development stage and with longer drought duration. The recovery of leaf functional 24 traits of the plants experienced historical-drought following re-irrigating was not fully 25 restored to the level of the plants subjected to ample and normal water status; and the 26 strength of recovery was proportional to the persistence of pre-drought episodes. The 27 relationship of Asat with SPAD depends on water status and plant development. A 28 principal component analysis can well denote the change patterns in responses to 29 water status treatments with plant development. The results may give an insight into 30 . CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/170258 doi: bioRxiv preprint first posted online Jul. 30, 2017;