旱柳枝条皮层叶绿体的光化学特性及结构的特化
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摘要
【目的】皮层光合对CO2的再固定可增加植株的碳收益,在叶片光合受阻时保障植株的生存延续。光合作用决定于叶绿体的结构和功能,研究皮层叶绿体的光化学特性及其结构的特化,可为揭示皮层光合运行、调节的生理和分子机制奠定基础。【方法】以旱柳当年生枝条为材料,在明确枝条中叶绿体的分布及其光化学效率的基础上,解析枝条皮层叶绿体与叶片叶绿体的光化学特性和结构的差异。【结果】旱柳枝条从髓到表皮均有叶绿体分布,皮层组织叶绿体的最大光化学效率最高,显著高于维管组织和髓。枝条皮层叶绿体的叶绿素b与叶绿素a、类胡萝卜素与总叶绿素的比例显著高于叶片叶绿体。枝条皮层叶绿体的PSⅡ激发能分配比例是叶片叶绿体的1.4倍。皮层叶绿体较叶片叶绿体具有较高的长、短轴比例。皮层叶绿体具有完整的亚细胞器结构,其中基粒片层占总片层数的比例、淀粉粒占叶绿体的比例显著高于叶片叶绿体。【结论】皮层组织叶绿体是枝条光合的主要贡献者。皮层叶绿体通过增加受光面积、提高天线色素比例,增加对枝条中有限光能的捕捉;通过提高光保护色素的比例减轻光氧化胁迫;通过增加类囊体的垛叠面积,促进光能向反应中心PSⅡ的传递;通过储藏淀粉,为枝条的非结构性碳水化合物需求提供保障。皮层叶绿体通过对光合色素组成的调整和亚细胞器结构的特化来适应枝条内的理化环境,最大限度地利用枝条中有限的光能。
【Objective】 Corticular photosynthesis is the process of CO2 re-fixation which derived from respiration and transpiration streaming, it could increase carbon income and guarantee plant survival when leaf photosynthesis is inhibited. Photosynthesis is determined by the structure and function of chloroplast. The study of photochemical characteristics and structure specializations of cortex chloroplast was to reveal the physiological and molecular mechanism of operation and regulation of corticular photosynthesis. 【Method 】 New twigs of Salix matsudana were taken as the experimental material,the chloroplast distribution in cross section and its photochemical efficiency were illustrated. On the basis of that,the differences of photochemical characteristic and structure between twig and leaf were analyzed.【Result】The results showed that chloroplast distribution from pith to epidermis in twig,and the max photochemical efficiency of PSⅡ of cortex was the highest,significantly higher than vascular tissue and pith. The ratio of chlorophyll a to chlorophyll b and carotenoid to total chlorophyll of cortex chloroplast were significantly higher than leaf chloroplast. The proportion of excited energy allocation of PSⅡ of cortex chloroplast was 1. 4 times of leaf chloroplast. The ratio of long to short axis of cortex was larger. The sub-organelle structure was complete in cortex chloroplast,and the ratio of grana lamella to total lamellas and starch grain area to whole chloroplast was significantly higher than leaf chloroplast. 【Conclusion 】 Cortex chloroplasts are the main contributor to twig photosynthesis. In order to capture the limited light in the tissues of twigs andto reduce photo-oxidative stress,the ratio of antenna pigment,light exposed area and the ratio of light protective pigment were increased. For promoting excited energy allocation to PSⅡ reaction center,the proportion of thylakoid stack area was increased. And cortex chloroplast guaranteed the demand for nonstructural carbohydrates through starch accumulation.Collectively,dependent on the adjustment of photosynthetic pigments composition and the specialization of sub-organelle structures,cortex chloroplast adapted to the physicochemical environment and made maximum use of the limited light energy inside the twigs.
【Objective】 Corticular photosynthesis is the process of CO2 re-fixation which derived from respiration and transpiration streaming, it could increase carbon income and guarantee plant survival when leaf photosynthesis is inhibited. Photosynthesis is determined by the structure and function of chloroplast. The study of photochemical characteristics and structure specializations of cortex chloroplast was to reveal the physiological and molecular mechanism of operation and regulation of corticular photosynthesis. 【Method 】 New twigs of Salix matsudana were taken as the experimental material,the chloroplast distribution in cross section and its photochemical efficiency were illustrated. On the basis of that,the differences of photochemical characteristic and structure between twig and leaf were analyzed.【Result】The results showed that chloroplast distribution from pith to epidermis in twig,and the max photochemical efficiency of PSⅡ of cortex was the highest,significantly higher than vascular tissue and pith. The ratio of chlorophyll a to chlorophyll b and carotenoid to total chlorophyll of cortex chloroplast were significantly higher than leaf chloroplast. The proportion of excited energy allocation of PSⅡ of cortex chloroplast was 1. 4 times of leaf chloroplast. The ratio of long to short axis of cortex was larger. The sub-organelle structure was complete in cortex chloroplast,and the ratio of grana lamella to total lamellas and starch grain area to whole chloroplast was significantly higher than leaf chloroplast. 【Conclusion 】 Cortex chloroplasts are the main contributor to twig photosynthesis. In order to capture the limited light in the tissues of twigs andto reduce photo-oxidative stress,the ratio of antenna pigment,light exposed area and the ratio of light protective pigment were increased. For promoting excited energy allocation to PSⅡ reaction center,the proportion of thylakoid stack area was increased. And cortex chloroplast guaranteed the demand for nonstructural carbohydrates through starch accumulation.Collectively,dependent on the adjustment of photosynthetic pigments composition and the specialization of sub-organelle structures,cortex chloroplast adapted to the physicochemical environment and made maximum use of the limited light energy inside the twigs.
引文
蔡锡安,曾小平,陈远其.2015.树干皮层光合作用---生理生态功能和测定方法.生态学报,35(21):6909-6922.(Cai X A,Zeng X P,Chen Y Q.2015.Stem corticular photosynthesis:ecophysiological functions and their measurement.Acta Ecologica Sinica,35(21):6909-6922.[in Chinese])
陈登举,高培军,吴兴波,等.2013.毛竹茎秆叶绿体超微结构及其发射荧光光谱特征.植物学报,48(6):635-642.(Chen D J,Gao P J,Wu X B,et al.2013.Chloroplast ultrastructure and emission fluorescence spectrum characteristics for stems of Phyllostachys pubescens.Acta Chimica Sinica,48(6):635-642.[in Chinese])
陈悦.2007.植物光合机构的捕光调节.上海:中国科学院上海生命科学研究院博士学位论文.(Chen Y.2007.The regulation of light harvesting in the photosynthetic apparatus of plants.Shanghai:Ph D thesis of Shanghai Institutes for Biological Science,CAS.[in Chinese])
高俊凤.2006.植物生理学实验指导.北京:高等教育出版社,74-77.(Gao J F.2006.Experimental guidance for plant physiology.Beijng:Higher Education Press,74-77.[in Chinese])
王文杰,祖元刚,王慧梅.2007.林木非同化器官树枝(干)光合功能研究进展.生态学报,27(4):1583-1595.(Wang W J,Zu Y G,Wang H M,et al.2007.Review on the photosynthetic function of non-photosynthetic woody organs of stem and branches.Acta Ecologica Sinica,27(4):1583-1595.[in Chinese])
阳成伟,彭长连,陈贻竹,等.2004.超高产杂交稻剑叶的光抑制及其77K荧光光谱特性.作物学报,30(1):21-25.(Yang C W,Peng C L,Chen Y Z,et al.2004.Photo-inhibition and77K fluorescence spectra in the flag leaves of superhigh hybrid rice(Oryza sativa L.).Acta Agronomica Sinica,30(1):21-25.[in Chinese])
张金尧,刘俊祥,巨关升,等.2014.旱柳非叶光合组织(皮层)叶绿体光合特性.林业科学,50(11):30-35.(Zhang J Y,Liu J X,Ju G S,et al.2014.Chloroplast photosynthetic characteristics of non-leaf photosynthetic tissues(cortex)of Salix matsudana.Scientia Silvae Sinicae,50(11):30-35.[in Chinese])
Avila E,Herrera A,Tezara W.2014.Contribution of stem CO2fixation to whole-plant carbon balance in nonsucculent species.Photosynthetica,52(1):3-15.
Cernusak L A,Cheesman A W.2015.The benefits of recycling:how photosynthetic bark can increase drought tolerance.New Phytologist,208(4):995-997.
Kotakis C H,Petropoulou Y,Stamatakis K,et al.2006.Evidence for active cyclic electron flow in twig chlorenchyma in the presence of an extremely deficient linear electron transport activity.Planta,225(1):245-253.
Levizou E,Petropoulou Y,Manetas Y.2004.Carotenoid composition of peridermal twigs does not fully conform to a shade acclimation hypothesis.Photosynthetica,42(2):591-596.
Nilsen E T.1995.Stem photosynthesis extent,patterns and role in plant carbon economy∥Gartner B.Plant stems:Physiology and functional morphology.San Diego:Academic Press,223-240.
Pfanz H,Aschan G,Langenfeld H R,et al.2002.Ecology and ecophysiology of tree stems:corticular and wood photosynthesis.Naturwissenschaften,89(4):147-162.
Pfanz H,Aschan G.2001.The existence of bark and stem photosynthesis in woody plants and its significance for the overall carbon gain.An eco-physiological and ecological approach//Esser K,Lüttge U,Kadereit J W,et al.Progress in Botany:vol.62.Berlin Heidelberg:Springer Press,477-510.
Pfanz H.2008.Bark photosynthesis.Trees,22(2):137-138.
SbA,Krekling T,Appelgren M.1995.Light quality affects photosynthesis and leaf anatomy of birch plantlets in vitro.Plant Cell Tissue Organ Culture,41(2):177-185.
Saveyn A,Steppe K,Ubierna N,et al.2010.Woody tissue photosynthesis and its contribution to trunk growth and bud development in young plants.Plant Cell and Environment,33(11):1949-1958.
Schmitz N,Egerton J,Lovelock C,et al.2012.Light-dependent maintenance of hydraulic function in mangrove branches:do xylary chloroplasts play a role in embolism repair?.New Phytologist,195(1):40-46.
Vandegehuchte M W,Bloemen J,Vergeynst L L,et al.2015.Woody tissue photosynthesis in trees:salve on the wounds of drought?New Phytologist,208(4):998-1002.
Wittmann C,Pfanz H.2014.Bark and woody tissue photosynthesis:a means to avoid hypoxia or anoxia in developing stem tissues.Functional Plant Biology,41(9):940-953.
Yang C W,Peng C L,Duan J,et al.2002.Responses of chlorophyll fluorescence and carotenoids biosynthesis to high light stress in rice seedling leaves at different leaf position.Acta Botanica Sinica,44(11):1303-1308.
陈登举,高培军,吴兴波,等.2013.毛竹茎秆叶绿体超微结构及其发射荧光光谱特征.植物学报,48(6):635-642.(Chen D J,Gao P J,Wu X B,et al.2013.Chloroplast ultrastructure and emission fluorescence spectrum characteristics for stems of Phyllostachys pubescens.Acta Chimica Sinica,48(6):635-642.[in Chinese])
陈悦.2007.植物光合机构的捕光调节.上海:中国科学院上海生命科学研究院博士学位论文.(Chen Y.2007.The regulation of light harvesting in the photosynthetic apparatus of plants.Shanghai:Ph D thesis of Shanghai Institutes for Biological Science,CAS.[in Chinese])
高俊凤.2006.植物生理学实验指导.北京:高等教育出版社,74-77.(Gao J F.2006.Experimental guidance for plant physiology.Beijng:Higher Education Press,74-77.[in Chinese])
王文杰,祖元刚,王慧梅.2007.林木非同化器官树枝(干)光合功能研究进展.生态学报,27(4):1583-1595.(Wang W J,Zu Y G,Wang H M,et al.2007.Review on the photosynthetic function of non-photosynthetic woody organs of stem and branches.Acta Ecologica Sinica,27(4):1583-1595.[in Chinese])
阳成伟,彭长连,陈贻竹,等.2004.超高产杂交稻剑叶的光抑制及其77K荧光光谱特性.作物学报,30(1):21-25.(Yang C W,Peng C L,Chen Y Z,et al.2004.Photo-inhibition and77K fluorescence spectra in the flag leaves of superhigh hybrid rice(Oryza sativa L.).Acta Agronomica Sinica,30(1):21-25.[in Chinese])
张金尧,刘俊祥,巨关升,等.2014.旱柳非叶光合组织(皮层)叶绿体光合特性.林业科学,50(11):30-35.(Zhang J Y,Liu J X,Ju G S,et al.2014.Chloroplast photosynthetic characteristics of non-leaf photosynthetic tissues(cortex)of Salix matsudana.Scientia Silvae Sinicae,50(11):30-35.[in Chinese])
Avila E,Herrera A,Tezara W.2014.Contribution of stem CO2fixation to whole-plant carbon balance in nonsucculent species.Photosynthetica,52(1):3-15.
Cernusak L A,Cheesman A W.2015.The benefits of recycling:how photosynthetic bark can increase drought tolerance.New Phytologist,208(4):995-997.
Kotakis C H,Petropoulou Y,Stamatakis K,et al.2006.Evidence for active cyclic electron flow in twig chlorenchyma in the presence of an extremely deficient linear electron transport activity.Planta,225(1):245-253.
Levizou E,Petropoulou Y,Manetas Y.2004.Carotenoid composition of peridermal twigs does not fully conform to a shade acclimation hypothesis.Photosynthetica,42(2):591-596.
Nilsen E T.1995.Stem photosynthesis extent,patterns and role in plant carbon economy∥Gartner B.Plant stems:Physiology and functional morphology.San Diego:Academic Press,223-240.
Pfanz H,Aschan G,Langenfeld H R,et al.2002.Ecology and ecophysiology of tree stems:corticular and wood photosynthesis.Naturwissenschaften,89(4):147-162.
Pfanz H,Aschan G.2001.The existence of bark and stem photosynthesis in woody plants and its significance for the overall carbon gain.An eco-physiological and ecological approach//Esser K,Lüttge U,Kadereit J W,et al.Progress in Botany:vol.62.Berlin Heidelberg:Springer Press,477-510.
Pfanz H.2008.Bark photosynthesis.Trees,22(2):137-138.
SbA,Krekling T,Appelgren M.1995.Light quality affects photosynthesis and leaf anatomy of birch plantlets in vitro.Plant Cell Tissue Organ Culture,41(2):177-185.
Saveyn A,Steppe K,Ubierna N,et al.2010.Woody tissue photosynthesis and its contribution to trunk growth and bud development in young plants.Plant Cell and Environment,33(11):1949-1958.
Schmitz N,Egerton J,Lovelock C,et al.2012.Light-dependent maintenance of hydraulic function in mangrove branches:do xylary chloroplasts play a role in embolism repair?.New Phytologist,195(1):40-46.
Vandegehuchte M W,Bloemen J,Vergeynst L L,et al.2015.Woody tissue photosynthesis in trees:salve on the wounds of drought?New Phytologist,208(4):998-1002.
Wittmann C,Pfanz H.2014.Bark and woody tissue photosynthesis:a means to avoid hypoxia or anoxia in developing stem tissues.Functional Plant Biology,41(9):940-953.
Yang C W,Peng C L,Duan J,et al.2002.Responses of chlorophyll fluorescence and carotenoids biosynthesis to high light stress in rice seedling leaves at different leaf position.Acta Botanica Sinica,44(11):1303-1308.