Work

Possible causes of extensive gametophyte abortion in Michelia alba

Year: 2026

Type: article

Abstract: Michelia alba (Magnoliaceae) is an economically important ornamental tree species characterized by extremely low natural seed set. To clarify the cytological basis of this reproductive failure, we conducted a comprehensive anatomical investigation of microsporogenesis, megasporogenesis, and male and female gametophyte development. Under normal developmental patterns, microspore tetrads were tetrahedral, isobilateral, or T-shaped and developed into bicellular pollen grains, whereas the female gametophyte followed a typical monosporic Polygonum-type pathway. However, severe abnormalities were consistently observed in both reproductive systems. >90% of pollen grains exhibited developmental arrest or structural collapse, frequently associated with premature tapetal disorganization and early contraction of the anther wall. Concurrently, over 90% of ovules failed to produce normal embryo sacs, with most embryo sacs arresting before or shortly after the stage of the functional megaspore; among >200 serially sectioned ovules, only two normal mature embryo sacs were detected. These observations provide clear anatomical evidence that extensive gametophyte abortion is a major factor of reproductive failure in M. alba , with female gametophyte arrest appearing to be an important factor limiting reproductive success. The study establishes a cytological foundation for understanding reproductive instability in Magnoliaceae and provides structural insights relevant to germplasm conservation and breeding.

Source: South African Journal of Botany

DOI: 10.1016/j.sajb.2026.06.025

Authors: Lijun Zhao, Haini Xu, Yang Sun, Guangli Wu, Liqiong Zhu

Institutions: Guangxi University, State Forestry and Grassland Administration, Guangxi Academy of Agricultural Science, Guangxi Vocational University of Agriculture

Language: English

Topic: Plant Reproductive Biology

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $2,750

Funders: National Natural Science Foundation of China, Guangxi University