%A GUO Liang, Eike LUEDELING, DAI Jun-Hu, XU Jian-Chu %T Differences in Heat Requirements of Flower and Leaf Buds Make  Hysteranthous Trees Bloom before Leaf Unfolding %0 Journal Article %D 2014 %J Plant Diversity %R 10.7677/ynzwyj201413081 %P 245-253 %V 36 %N 02 %U {https://journal.kib.ac.cn/CN/abstract/article_33309.shtml} %8 2014-03-25 %X

To clarify which agroclimatic requirements control the sequential occurrence of flowering and leaf unfolding in hysteranthous plants, Partial Least Squares (PLS) regression analysis was used to identify the chilling and forcing period of leaf and flower buds. The Dynamic Model and the Growing Degree Hour Model were applied to estimate the chilling and heat requirement for leaf unfolding and flowering, based on the phenological records of apricot and mountain peach and daily maximum and minimum temperature data in Beijing during 1963-1988. The results indicated that PLS regression analysis is a useful approach to calculate the chilling and heat requirements of plants when long term phenological observations are available. Leaf and flower buds were found to have similar chilling requirements but different heat requirements, which explained the earlier occurrence of flowering compared to leaf unfolding. The heat requirements of flower buds of apricot and mountain peach were 28297±8762 and 14572±5812 Growing Degree Hours, respectively, while heat requirements of vegetative buds were almost twice as high. In view of the importance and usefulness of phenological observations, specieslevel ground observations in China should be continued and extended.