Papaya pollen viability and the possibility of the existence of 2n pollen
Date Issued
2010
Date
2010
Author(s)
Yu, Chih-Ying
Abstract
Studying on the physiological characteristics and preservative methods of papaya pollen will be helpful for papaya breeding. Using FCR (fluorochromatic reaction) and in vitro germination assessed pollen viability of different sex types of tree, floral sex variation, flower and stamen position, and floral stage. The results indicate that the papaya pollen in vitro germination medium consisting of 10 % sucrose, 300 ppm calcium nitrate, 100 ppm boric acid resulted in better germination percentage. The pollen germination percentage and FCR test viability percentage of carpelloid flowers were of papaya pollens lower than these of normal perfect flower (elongate) in hermaphroditic papaya. However, the sex of papaya tree, anther position, and flower position do not affect the viability of papaya pollen. The maximum value of germination was obtained with pollen at the time of full bloom. The highest percentage of pollen germination was found in just anthesis and blooming flowers, pollinating on female flower in bloom also have the largest number of seed. Pollen have viability from one week before anthesis, but seed set was poor. The pistil are well fertilized from one week before anthesis. Some papaya has heterogeneous-sized pollen and meiotic abnormalities, such as the development of pollen mother cells are not synchronized, the formation of chromosome bridges; chromosome movement disturbances and micronuclei formation. Flow cytometric analysis of relative nuclear DNA contents in papaya pollen resulted in two peaks that indicate papaya pollen may have 2n pollen. The 2n pollen can be utilized for manipulating polyploidization in the papaya breeding.
Subjects
pollen in vitro germination
flower sex
flower age
stigma receptivity
seed set
flow cytometry
Type
thesis
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