Page 6 - 《广西植物》2025年第1期
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CHEN Ni ꎬ PENG Lihui ꎬ JIANG Haidu ꎬ YANG Zhe ꎬ JIANG Qiang ꎬ
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QIU Shuo ꎬ XIONG Zhongchen ꎬ WEI Xiao ꎬ CHAI Shengfeng
( 1. Guangxi Institute of Botanyꎬ Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences/ Guangxi Key Laboratory of
Plant Functional Phytochemicals and Sustainable Utilizationꎬ Guilin 541006ꎬ Guangxiꎬ Chinaꎻ 2. College of Tourism and
Landscape Architectureꎬ Guilin University of Technologyꎬ Guilin 541006ꎬ Guangxiꎬ Chinaꎻ 3. Yachang Orchid
National Nature Reserve Management Centerꎬ Baise 533209ꎬ Guangxiꎬ China )
Abstract: This study was carried out to determine the daily change of net photosynthetic rate (P )ꎬ light response
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curveꎬ CO response curveꎬ leaf chlorophyll content and leaf microstructure of four Dendrobium speciesꎬ including
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D. scoriarumꎬ D. lituiflorumꎬ D. lohohenseꎬ and D. aduncum. The purpose of this investigation was to learn more about
the photosynthetic characteristics of Dendrobium species. The results were as follows: (1) Dendrobium scoriarum and
D. aduncum had positive P during the daytimeꎬ with the maximum peak at 8:00—10:00 a.m.ꎬ and the nighttime P was
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lower than that during the daytimeꎬ and there was positive P . Dendrobium lituiflorum and D. lohohense showed a
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bimodal curve of P during the daytimeꎬ with positive P during the daytime and negative P during the nighttime. (2)
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Among the four species of Dendrobiumꎬ D. lituiflorum had the strongest photosynthetic capacityꎬ while D. lohohense had
the widest light adaptation range. (3) The initial carboxylation efficiency (α)ꎬ potential maximum net photosynthetic
rate (A ) and photorespiration rate (R ) of D. lituiflorum were significantly (P<0.05) greater than those of the other
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three Dendrobium species. (4) The leaf thickness (LT) of D. aduncum and D. scoriarum were greater than those of
D. lituiflorum and D. lohohenseꎬ while stomatal density (SD) showed an opposite trend. (5) The total chlorophyll
content (Chl)ꎬ chlorophyll a (Chla)ꎬ and chlorophyll b (Chlb) of D. lituiflorum were significantly (P<0.05) higher
than those of the other three Dendrobium species. (6) The mesophyll thickness (MT) was significantly (P< 0.05)
negatively correlated with maximum net photosynthetic rate (P )ꎻ SD was highly significant (P< 0.01) positively
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correlated with P ꎬ and significantly (P<0.05) positively correlated with potential maximum net photosynthetic rate
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(A )ꎻ total chlorophyll content ( Chl) was significantly ( P < 0. 05) positively correlated with P and A . In
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conclusionꎬ the four Dendrobium species may respond to low light levelsꎬ being affixed to tree trunksꎬ or growing in
stonyꎬ water ̄deficient settings by developing larger leaf pulp tissue and low stomatal density. The four Dendrobium
species total chlorophyll concentrationꎬ stomatal densityꎬ and leaf pulp thickness are significant determinants of their
photosynthetic potential. For the four Dendrobium species to flourish during introduction and cultivationꎬ it is helpful to
establish a proper light environment and raise the CO content adequately. The findings of this research can serve as a
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reference for the introduction and the preservation of genetic resources.
Key words: Dendrobiumꎬ photosynthetic propertiesꎬ crassulacean acid metabolism ( CAM)ꎬ leaf microstructureꎬ
chlorophyll content
石 斛 属 ( Dendrobium ) 隶 属 于 兰 科 原始森林和相似的温暖湿润的自然环境中( 刘张
(Orchidaceae) 树 兰 亚 科 ( Epidendroideae) 沼 兰 族 栋ꎬ2014)ꎮ 我国石斛属植物主要分布于秦岭、淮
(Malaxideae)ꎬ许多石斛种类不仅具有观赏价值ꎬ 河以南ꎬ30° N 以南地区ꎬ由南向北种类逐渐减少ꎬ
而且还具有很高的药用价值( 鲜小林等ꎬ2013ꎻ 李 云南和广西是我国石斛属植物资源种类分布最多
涛和何璇ꎬ2016)ꎮ 据杨红旗等(2021) 统计ꎬ目前 的 地 区 ( 龚 建 英 等ꎬ 2015 )ꎮ 滇 桂 石 斛 ( D.
我国共有石斛属植物 104 种ꎬ其中我国特有种 13 scoriarum)分布于我国广西、贵州西南部和云南东
种ꎬ除了霍山石 斛 ( Dendrobium huoshanense) 和 曲 南部ꎬ生于海拔约1 200 m 的石灰山岩石上或树干
茎石斛( D. flexicaule) 被列为一级保护植物外ꎬ其 上ꎻ喇叭唇石斛( D. lituiflorum) 分布于广 西 西 南
他均为我国二级重点保护野生植物ꎮ 石斛属多为 部、云南西南部ꎬ生于海拔 800 ~ 1 600 m 的山地阔
附生或岩生植物ꎬ主要生长在热带及亚热带地区 叶林中的树干上ꎻ罗河石斛( D. lohohense) 分布于