A Study on Pollen Morphology of Tribe Rhamneae (Rhamnaceae)in China

Abstract

Abstract:

Pollen morphology of 25 Chinese species, representing 6 five genera in the tribe

Rhamneae of Rhamnaceae, was examined under LM and SEM. Pollen grains are

subspheroidal or suboblate, obtuse-triangular in polar view, 3-colporate, with the polar axis

(P)10.4-28.7μm long and equatorial axis (E) 11.3-30.5μm long, P/E = 0.81-1.11. Colpi

generally narrow and long, ora lalongate, with two ends connected with the thinned part of

exine, forming a H-shape. Four thickenings were observed where colpi and ora cross, but

sometimes the thickenings were indistinct or formed a ring. The stratification indistinct. The

ornamentation of exine obscure or indistinctly reticulate under LM, but rugulose,

short-striate, rugulose-foveolate or reticulate under SEM.

The exine ultrastructure of Rhamnus ussuriensis was examined under TEM. It consists of

imperforate tectum, granular layer, foot layer and endexine. The tectum is rather thick with

uneven surface, while the granular layer is rather thin.

A key to the genera based on pollen characteristics is provided and the general

pollenmorphology of five genera, i.e. Sageretia, Rhamnus, Hovenia, Colubrina and Alphitonia,

is described respectively.

Based on pollen size, the four thickenings and the ornamentation, the five genera under

study may be distinguished from each other. For example, pollen grains are smaller in

Sageretia; the four thickenings are larger and distinct in Hovenia and Alphitonia. However,

the ornamentation is short-striate under SEM in Hovenia and Alphitonia, while reticulate in

the Colubrina and Rhamnus ( Subgen. Rhamnus) .Two different concepts of Rhamnus exist

among taxonomists. Heppeler and Suessenguth divided Rhamnus into two subgenera

(Subgen. Frangula and Subgen. Rhamnus), whereas Grubov separated Subgen. Frangula

from Rhamnus as an independent genus. According to the pollen morphology, the separation

is reasonable.

Key words: Pollen morphology, Rhamnaceae, Rhamneae

Zhang Yu-Long, Chen Yi-Ling. A Study on Pollen Morphology of Tribe Rhamneae (Rhamnaceae)in China[J]. .

[1]	WANG Wei, ZHAO Nan-Xian. Pollen morphology of the Araceae from China [J]. , 2002, 40(6): 517-529.
[2]	SUN Kun, CHEN Jia-Kuan, ZHANG Zhi-Yun. Pollen morphology of 15 species in nine genera of the Hydrocharitaceae [J]. , 2002, 40(6): 490-500.
[3]	LIU Jia-Xi, ZHANG Yu-Long, NING Jian-Chang, ZHAO Yun-Yun, LI Ya-Xuan, ZHANG Jing-Mei. Pollen morphology of the tribe Cynoglosseae of Boraginoideae (Boraginaceae) in China [J]. , 2001, 39(6): 515-522.
[4]	LI Wei-Lin, HE Shan-An, GU Yin, SHU Pu, PU Zu-Mao. Pollen morphology of the genus Rubus from China [J]. , 2001, 39(3): 234-247.
[5]	. [J]. , 2001, 18(1): 11-11.
[6]	SUN Cheng-Ren. Pollen morphology of the Schisandraceae and its systematic significance [J]. , 2000, 38(5): 437-445.
[7]	XI Yi-Zhen, LANG Kai-Yong, HU Yu-Shi. Pollen Morphology of Neottianthe (Orchidaceae) and Its Taxonomic Significance [J]. , 1998, 36(6): 496-502.
[8]	WANG Ping-Li, PU Fa-Ting, ZHENG Zhong-Hua. Palynological Evidence for Taxonomy of Trigonobalanus (Fagaceae) [J]. , 1998, 36(3): 238-241.
[9]	Wang Qing-feng, Zhang Zhi-yun, Chen Jia-kuan. Pollen Morphology of the Alismataceae [J]. , 1997, 35(3): 225-235.
[10]	Huang Jin-ling, Hong De-yuan. Pollen Morphology in the Subtribe Aspidistrinae (Liliaceae s. l.) [J]. , 1997, 35(2): 117-124.
[11]	Huang Lu-qi, Yang Bin, Yue Chong-xi, Cheng Chung-yung. Pollen Morphology of Trichosanthes and Its Taxonomic Significance [J]. , 1997, 35(2): 125-135.
[12]	Wang Jian-xin, Feng Zhi-jian. A Study on the Pollen Morphology of the Genus Polygonum in China [J]. , 1994, 31(3): 219-231.
[13]	Xi Yi-zhen. Studies on Pollen Morphology and Exine Ultrastructure in Cephalotaxaceae [J]. , 1993, 31(5): 425-431.
[14]	Ning Jian-chang, Xi Yi-zhen, Zhang Yu-long. Pollen Morphology of Microula Benth. and Allied Genera (Boraginaceae) [J]. , 1993, 31(4): 318-328.
[15]	Di Wei-zhong, Ren Yi, Wang Guo-rui. A Study on Pollen Morphology of the Genus Viburnum from China [J]. , 1993, 31(2): 153-161.

A Study on Pollen Morphology of Tribe Rhamneae (Rhamnaceae)in China

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