Effect of Photoperiod on Isoenzymic Composition of Citrus and Poncirus.

Long day photoperiod treatments given to Dancy and Clementine tangerines (Citrus reticulata Blanco.), the Mineota tangelo (C. paradisi Macf. x C. reticulata Blanco.) and the Rubideaux trifoliate (Poncirus trifoliata (L.) Raf.) produced 1.5 to 2.5 times the stem area, total linear growth and number of branches compared to short day treatments. Growing shoot tips were subjected to electrophoretic analyses of the isoenzymic composition of esterases, leucine aminopeptidases, peroxidases and amylases. Differences were observed in the number and activity of the isoenzymes between the short and the long day treated plants of the three Citrus species and Rubideaux trifoliate orange. The possible significance of these differences is discussed in relation to the growth in response to the response to the photoperiodic treatments. [ABSTRACT FROM AUTHOR]