Intraspecific Pollen Morphology Variation and Its Responses to Environmental Factors of Wild Cathaya argyrophylla Chun Et Kuang Endemic to China

Abstract

Studying the pollen morphology of this remnant and endemic wild species of Cathaya argyrophylla can be of use for paleobiologists. During this study, 23 genotypes sampled from four natural populations in two regions of Hunan Province, China. A total of 460 pollen grains were analyzed for seven quantitative and seven qualitative traits (including five new traits). Three quantitative traits (B, P, and A) (Width of the saccus (B); Length of the polar axis (P); Length of the saccus (A)) and four qualitative traits (O-CO, B-SD, O-CSR, and B-SU) (Pollen corpus outlined in the polar distal view (O-CO); Whether the outline of two sacci was distinct or not in the polar proximal view (B-SD); Roughness degree between corpus from the polar proximal view and the sacci from the polar distal view (O-CSR); Whether the overall size of two sacci was uniform or not (B-SU)) were the diagnostic pollen features that could possible to differentiate one population and classified 23 samples into two, three, or four clusters. Furthermore, 24 environmental factors were evaluated and precipitation factors effected more on pollen morphology than geographic and temperature factors, which including annual precipitation (bio12), precipitation of wettest month and driest month (bio13, bio14), precipitation seasonality (bio15) and monthly averaged precipitation in May (05-precip). The main precipitation and temperature factors exhibited positive and negative correlation with pollen size (B and E (Equatorial diameter (E))), respectively. This article provides deeper insight into intraspecific variability of pollen grains of C. argyrophylla, which have been investigated for the first time. In addition, the insights gained from this study could assist with the seed breeding and population reproduction of the endangered C. argyrophylla tree.

The diversity and abundance of bacterial and fungal communities in the rhizosphere of Cathaya argyrophylla are affected by soil physicochemical properties

“…C. argyrophylla is discontinuously distributed in the subtropical mountains of Guangxi, Hunan, Sichuan, and Guizhou provinces ( Fan et al, 2020 ). The endangered status of C. argyrophylla can be attributed to poor germinability, poor interspecific competition, and low adaptive ability to new environments ( Xiao et al, 2022 ), as well as disturbances caused by broadleaf species during succession, which have led to drastic changes in genetic diversity and population structure. As the only extant species in the Cathaya genus, the extinction of C. argyrophylla would cause ecological destabilization, and could have profound effects on 10–30 species in its closely related ecosystem ( Forest et al, 2018 ).…”

“…As the only extant species in the Cathaya genus, the extinction of C. argyrophylla would cause ecological destabilization, and could have profound effects on 10–30 species in its closely related ecosystem ( Forest et al, 2018 ). Many scholars have conducted studies on the features of C. argyrophylla populations that have contributed to its endangered status, including community structure types, survival environment, reproductive patterns, and biological traits ( Vaario et al, 2006 ; Wang and Ge, 2006 ; Wang et al, 2010 ; Xiao et al, 2022 ). Artificial propagation has been attempted via a seedling raising and regeneration system ( Erfmeier et al, 2019 ; Zheng et al, 2021 ).…”