The Exploration of Flowering Mechanisms in Cherry Plants

Flowering cherry (<i>Cerasus</i> sp.) are significant spring-blooming trees. However, the short blooming period and the rarity of early and late-flowering varieties limit their use in gardens in northern China. The experiment incorporated annually early-flowering species such as <i>Cerasus discoidea</i>, <i>Cerasus pseudocerasus</i> ‘Introtsa’, <i>Cerasus dielsiana</i>, <i>Cerasus campanulata</i> ‘Youkou’, <i>Cerasus yedoensis</i> ‘Somei-Yoshino’, and <i>Cerasus spachiana f. ascendens</i>, as well as twice-a-year flowering species like <i>Cerasus subhirtella</i> ‘Autumnalis’ and <i>Cerasus subhirtella</i> ‘Accolade’. We observed the timing of natural events and growth measurements for specific plants over a span of two years. This research involved a thorough examination of their ability to withstand cold temperatures, considering their physiological aspects. We examined the levels of nutrients and hormones in the flower buds at various stages of development in plants that bloom yearly and every two years. The findings indicated that <i>C. subhirtella</i> ‘Autumnalis’ is adaptable, offering the lengthiest autumn blooming phase lasting 54 days. The hierarchy of cold tolerance was as follows: <i>C. pseudocerasus</i> ‘Introtsa’ > <i>C. discoidea</i> > <i>Cerasus</i> × <i>subhirtella</i> ‘Autumnalis’ > <i>C. dielsiana</i> > <i>C.</i> ‘Youkou’. Furthermore, the soluble protein content in leaves increased before autumn flower buds’ sprout of twice-a-year flowering varieties but declined in <i>C. yedoensis</i> ‘Somei-Yoshino’ within the same time. We determined that changes in nutrient content significantly contribute to the autumn opening of <i>C. subhirtella</i> ‘Autumnalis’ robust short branch flower buds. During the final phase of flower bud development, the rise in trans-Zeatin-riboside (ZR) and indolacetic acid (IAA) promotes the initiation of the first flowering period in <i>C. subhirtella</i> ‘Autumnalis’ prior to its mandatory hibernation. The occurrence of secondary flowering involves a multifaceted regulatory process. These findings serve as valuable references for delving deeper into the mechanisms governing cherry blossom formation and secondary flowering.