Histological and Cytological Characterization of Anther and Appendage Development in Asian Lotus (Nelumbo nucifera Gaertn.).

Dasheng Zhang,Shaohua Wu,Qingqing Liu,Fengluan Liu,Qing Chen,Lijie Cui,Jie Xu,Daike Tian,Wen Shao

doi:10.3390/ijms20051015

Abstract

The lotus (Nelumbo Adans.) is a perennial aquatic plant with important value in horticulture, medicine, food, religion, and culture. It is rich in germplasm and more than 2000 cultivars have been cultivated through hybridization and natural selection. Microsporogenesis and male gametogenesis in the anther are important for hybridization in flowering plants. However, little is known about the cytological events, especially related to the stamen, during the reproduction of the lotus. To better understand the mechanism controlling the male reproductive development of the lotus, we investigated the flower structure of the Asian lotus (N. nucifera). The cytological analysis of anther morphogenesis showed both the common and specialized cytological events as well as the formation of mature pollen grains via meiosis and mitosis during lotus anther development. Intriguingly, an anatomical difference in anther appendage structures was observed between the Asian lotus and the American lotus (N. lutea). To facilitate future study on lotus male reproduction, we categorized pollen development into 11 stages according to the characterized cytological events. This discovery expands our knowledge on the pollen and appendage development of the lotus as well as improving the understanding of the species differentiation of N. nucifera and N. lutea.

Highlights

The Lotus (Nelumbo) is a perennial aquatic plant with ornamental, medicinal, edible and cultural importance [1,2,3]
To better understand the process and characteristics of the male reproductive development of the Asian lotus in comparison with previous reports on the American lotus, we investigated the flower and anther structure, anther morphogenesis, and pollen formation of a wild type Asian lotus
The ultrathin sections were observed under a transmission electron microscope (Tecnai G2 Spirit Biotwin, FEI, Hillsboro, OR, USA). This is the first report of the pollen and anther development in the Asian lotus

Summary

Introduction

The Lotus (Nelumbo) is a perennial aquatic plant with ornamental, medicinal, edible and cultural importance [1,2,3]. The Asian lotus, called the sacred lotus, has been domesticated in Asia for about 7000 years and is cultivated as a major crop where its rhizomes and seeds are used as vegetables in China and Southeast Asian countries [5]. It is the national flower of India and one of the traditional flowers of China and Vietnam. As a famous ornamental plant, lotus is widely planted in water gardens, ponds, lakes and rivers to beautify and purify the environment It produces a series of secondary metabolites with important medicinal functions, including flavonoids, alkaloids, triterpenoids, steroids, glycosides and polyphenols from the leaves, flowers, seedpods and seeds [8]

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Discussion

Conclusion