采用叶绿素荧光图像分析手段,结合叶绿素含量和主枝生长量测定,研究了沙地云杉、青海云杉、蓝云杉、白扦PSⅡ光化学效率和非光化学能量耗散的光响应特性及对稳态光强的适应性.结果表明:在相同生境和管理条件下,15a苗龄的4种云杉属植物生长势态良好,均能适应民勤荒漠气候环境;蓝云杉针叶的叶绿素含量较高,而青海云杉的叶绿素a、b比值(Chl a/b)较低;4种植物PSⅡ光化学效率的光响应曲线相似,但蓝云杉PSⅡ非光化学猝灭系数(NPQ)的光响应明显有别于其余3种;150μmol m-2 s-1低光强下4种植物间NPQ的差异与PSⅡ最大光化学量子效率(Fu/Fm)一致,是内禀光合特性的反映;1500μmolm-2s-1高光强下的NPQ和PSⅡ最大效率(Fv′/Lm′)在4云杉属植物间没有差异,呈现光合生理的趋同适应.综合比较分析可知,蓝云杉和白扦在低光强具有略低的PSⅡ非光化学猝灭能力,在高光强具有相对高的PSⅡ运行效率(Fq′/Fm′),光驯化适应能力较大;沙地云杉和青海云杉具有几乎一致的PSⅡ光化学和非光化学猝灭特性,其耐荫性和喜光性相近;4种云杉属植物光合机构对干旱荒漠生境的驯化适应具有趋同性,可作为我国北方防护林建设和城市绿化的重要树种.%Picea mongolica,Picea crassifolia,Picea pungens and Picea meyeri are the four spruce species growing in Minqin Desert Botanical Garden (38°35′ N,102°58′ E;1378 m asl).In combination with the analysis of photosynthetic pigments in needles and annual growth of main braches,the chlorophyll fluorescence imaging of needles were performed with prepared protocols using CF imager to determine the PS Ⅱ photochemical efficiency and non-photochemical energy dissipation,and their adaptability to steady-state light intensity.The results showed that,in the same habitat and management,the four spruce species seedlings aged 15 years exhibited similar good growth behavior and all adapted to desert climatic environment;the total chlorophyll contents were fairly higher in P.pungens while specific ratio of chlorophyⅡ a to b (Chl a/b) was comparatively lower in P.crassifolia.Among the four species their photosynthetic response curves of PS Ⅱ photochemical efficiency were similar,but P.pungens illustrated an obviously different photosynthetic response in PS Ⅱ non-photochemical quenching coefficient (NPQ) from the other three.The consistent trend of NPQ irradiated with 150 μmol m 2 s-1 low actinic light for 10 min and PS Ⅱ photochemical maximum quantum efficiency (Fv/Fm) adapted for 20 min in dark exhibited the intrinsic photosynthetic characteristics of the species.That nearly no dissimilarities among the four species in NPQ irradiated with 1 500 μmol m-2 s-1 high actinic light and in PS Ⅱ maximum efficiency (Fv′/Fm′) done with low actinic light demonstrated their physiological expressions of convergent adaptation.Comprehensive comparative analysis indicates that P.pungens and P.meyeri have lower ability in PS Ⅱ non-photochemical quenching in low light intensity,but a relatively higher PS Ⅱ operating efficiency (Fq ′/Fm′) in high light intensity,thus a greater ability for light-acclimation;while P.mongolica and P.crassifolia share almost unanimously PS Ⅱ photochemical and non-photochemical characteristics,and similar shade tolerance and light-demanding;the complete presentation of PS Ⅱ photosynthetic physiological characteristics in the four species indicates their convergent adaptability to Minqin arid desert climate,so they are feasibly important tree species in the northern shelter forestry construction in China and in the urban greening in dry areas.
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