Studies On Biological Features Of Flowering And Tissue Culture Of Spathiphyllum

Spathiphyllum belongs to the Araceae.Its leaf color and flower type are unique,and it is also called silver leaf taro or bract taro.It is an important international indoor ornamental flowering plant and indoor air purification plant.The main varieties of Spathiphyllum come from abroad,and the new varieties of Spathiphyllum mostly rely on traditional cross breeding.At present,the breeding goal is focused on plant type and height,leaf glossiness and color,and spathe size,color and quantity etc.So far,few study on flowering biological features were reported.There are more and more studies on tissue culture of Spathiphyllum,but no common multiplication and rooting culture conditions are proposed.To deeply understand the biological features of flowering of Spathiphyllum,the plant morphological characteristics,the morphological and histological observation of floral bud differentiation,and the flower characteristics of different varieties were investigated in this study.The development process of megaspore and gametophyte,determination of pollen viability,characteristics of pollen germination,changes of pollen vigor were also studied.Meanwhile,the optimization of shoot proliferation and rooting conditions of Spathiphyllum plantlet were explored.Our study will provide valuable information for the Spathiphyllum breeding.The results are as follows.1.Four different varieties of Spathiphyllum were used as materials.The morphological characteristics,the morphology and organization of floral bud differentiation,and the flower organs structure and pollen dispersal characteristics were studied.The results showed that the morphological characteristics were similar in different medium plant types and in different small plant types,but different between medium plant types and small plant types of Spathiphyllum.The floral bud differentiation of Spathiphyllum could be divided into 6 periods according to floral development.There were commonly three kinds of florets on the spadix of Spathiphyllum:(1)flower with four petals,four stamens and a pistil;(2)flower with five petals,five stamens and a pistils;(3)flower with six petals,six stamens and a pistil.There were different florets distributed on different parts of spadix.The floret ovary of Spathiphyllum consisted of two or three carpels and enclosed two or three locule and axospermous.The locule number in the ovary of different types of flower was different,and axospermous number of different varieties of Spathiphyllum flowers within the locule was also different.The pollen was sent to the corolla surface with the elongated anther filament,cracking under suitable conditions.2.By using different cultivars as the materials,the microspore and gametophyte development process,the pollen viability,and the activity changes during pollen germination of spathiphyllum were investigated.The results showed that the cytoplasmic division was continuous at the early stage of microspores development and the microspores are arranged quadrilaterally.The development of microspores whin a pollen capsule was not synchronized,and the mature pollen was a two-cell pollen.From outside to inside of the anther wall,the epidermis,the inner wall,the middle layer and the tapetum were arranged orderly.The inner wall of the anther was formed in the later stage.There was a great difference in pollen vitality of different varieties of pollen.And the pollen viability changes sharply and is unstable during the period of pollen dispersal.The suitable time for pollen germination was 1 Oh at 25 ℃.3.By using ’SP5’ aseptic seedlings as materials,the effect of auxin and cytokinin ratio,different medium and different concentrations of sucrose on shoot proliferation and rooting of spathiphyllum plantlet were studied.The results showed that the optimum medium for shoot proliferation was MS + 6-BA3.0 mg/l+NAA 0.1 mg/l + sucrose 30 g/l + agar 5.5 g/l,pH 5.6,and the optimal rooting medium was 1/4MS + IBA0.1 mg/l + sucrose 30 g/l + agar 5.5 g/l,pH5.6.