Anatomical and hormonal studies of floral and fruiting behavior of phoenix dactylifera, cv. barhee

This study was conducted on date palm trees,cv Barhee grown in Basrah region to investigate hormonal levels and anatomical characters of floral and fruiting behavior during the growing season of 2013. Results showed that auxins and gibberellins concentrations in flowers and fruits were higher at early stages of fruit development and then decreased, gradually as the fruit of both normal and abnormal behavior advance toward maturity stage. It was noticed that fruit of normal development had higher concentrations of both auxins and gibberellins than those of abnormal behavior with the exception of abnormal fruits having a slightly higher concentration of auxins at the period of 55 days after pollination. Anatomical sections of internal structure of normal and abnormal flowers and fruits showed the development of flower in normal behavior, but in abnormal behavior the style is not connected firmly with the ovary causing its death and then failure of pollen grains formation. Also, the style and stigma are separated from the ovary resulting in failure of the process of fertilization, as well as clear disconnection from the ovary. In longitudinal and cross sections of the ovary, it was found that no zygote was detected in the ovary during the developmental stages of abnormal flower. Abnormal male flower had small anther and small pollen sac, with pollen grains being severely reduced in abnormal anther as compared with that of normal anther. Eventually, most of the parthenocarpic fruits remained on bunches until harvest time and have significant influence on the economic value of fruits in this genotype.