The superficial layer cell of basic petal becomes matic activity and formes the primordium nectary.The pre-nectar may be provided by phloem that is round the nectariferous tissue.

• 原蜜汁由蜜腺周围的维管束提供，经产蜜组织加工后，由分泌表皮外薄的角质层泌出。