Critical Periods and Changes Involved in Hemerocallis lilioasphodelus Floral Transition

Abstract

Hemerocallis is a valuable commercial perennial with prominent flowers. In this study, a wild variety of Hemerocallis lilioasphodelus L. cv. Licheng 7 (H. lilioasphodelus, LC7) from China was chosen as the experimental material due to its stable flowering trait in cultivation. Three main conclusions were obtained. Our observations revealed that the transition from vegetative to reproductive growth had a strong relationship with shoot apical meristem (SAM) fasciation, and the process was outlined in four morphological transitional stages. In addition, we detected a temporary increase in soluble sugar in the shoot tip, which was suggested to be a physiological indicator of inflorescence primordium initiation. In addition, the full-length sequences of two phosphatidylethanolamine-binding protein (PEBP) family genes from the wild species LC7 were cloned. From quantitative RT-PCR (qRT-PCR) and correlation analyses, we elucidated that the two PEBP family genes were correlated with some SAM morphological traits and involved in the regulation of the floral transition of the wild species LC7. To the best of our knowledge, this study provided a precious resource investigation of critical periods in the floral transition of H. lilioasphodelus, which will be recommended for regulation of the flowering time in perennials in the future.