Pollen morphology of tribes Alsineae and Sperguleae (Caryophyllaceae) and its systematic significance

Abstract

Pollen morphology of 79 species, one subspecies and eight varieties representing nine genera of tribe Alsineae and two of tribe Sperguleae was studied using light microscopy (LM) and scanning electron microscopy (SEM). Among them, 53 species and eight varieties (22 species of which are endemic to China) were reported for the first time. The results demonstrate that the number of pores, the pollen surface ornamentation and the density of microechini have important systematic significance. The surface ornamentation can be divided into three types, namely microechinate-perforate, microechinate-punctate, and microechinate-punctate-perforate. Pollen characteristics support: (i) isolation of Arenaria subgenus Odontostemma from Arenaria and reclassification of Arenaria subgenus Odontostemma to Odontostemma; (ii) isolation of Cerastium subgenus Dichodon from Cerastium and reclassification of Cerastium subgenus Dichodon to Dichodon; (iii) isolation of Minuartia subgenus Rhodalsine from Minuartia and reclassification of Minuartia subgenus Rhodalsine to Rhodalsine; (iv) isolation of Rhodalsine from tribe Alsineae and reclassification of Rhodalsine into tribe Sperguleae; and (v) isolation of Sagina from tribe Alsineae. In addition, the relationships of Arenaria subgenus Eremogone and Arenaria subgenus Eremogoneastrum to tribe Alsineae need to be further studied. Furthermore, pollen characteristics indicate that tribe Alsineae is more evolved than tribe Sperguleae.

Keywords:

• Alsineae
• pollen morphology
• Sperguleae
• systematics

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant numbers 31270276 and 30470106], the Program for Changjiang Scholars and Innovative Research Team in University [grant number IRT-17R75] and Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-Year Plan [grant number IDHT20180518].

Notes on contributors

Xinci Cui

XINCI CUI graduated with a BSc in biological sciences from the College of Life Sciences of Capital Normal University, Beijing, China. She is studying for an MSc in botany at the same institution. She specialises in the palynology and taxonomy of the Caryophyllaceae.

Yunyun Zhao

YUNYUN ZHAO is a professor in the College of Life Sciences, Capital Normal University, Beijing, China. She received a BSc and an MSc in botany from the College of Life Sciences of Capital Normal University, Beijing, China, and a PhD in biochemistry and molecular biology from China Agricultural University, Beijing, China. She researches plant systematics and evolution.

Chunhai Zhao

CHUNHAI ZHAO received his BSc and MSc in botany from the College of Life Sciences of Capital Normal University. He specialises in the palynology of the modern floras of several Chinese ecosystems.

Jiaxi Liu

JIAXI LIU is a professor in the College of Life Sciences, Capital Normal University, Beijing, China. He received BSc and MSc in botany from Harbin Normal University, Heilongjiang, China, and his PhD in ecology from Northeast Forestry University, Heilongjiang, China. He researches the palynology and embryology of the modern floras of several Chinese ecosystems.