酸枣根系结构可塑性对自然梯度干旱生境的适应机制
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摘要
根系是植物吸收水分和养分的主要器官,是直接接触土壤最先感受土壤逆境胁迫的部位。在干旱环境中,植物根系的结构特征必定发生改变以维持正常的生物机能而生存。目前,关于根系解剖结构的研究大多集中于根系的某一特定结构对单一逆境因子的响应。以生长在烟台-石家庄-银川-吐鲁番不同地域气候条件形成的自然梯度干旱环境中的酸枣为试验材料,应用植物显微技术研究酸根系结构的可塑性对不同自然梯度干旱环境的适应机制,结果表明:酸枣根的初生结构包括表皮、皮层和维管柱,表皮位于幼根的最外层,由单层体积较小、紧密排列的表皮细胞组成。皮层占根初生结构的大部分比例,由体积较大的多层薄壁细胞组成,薄壁细胞近似圆球形,数目众多,呈环形分布。维管柱位于最内层,细胞小而密集,由中柱鞘、初生木质部、初生韧皮部及薄壁细胞组成。随生境干旱加剧,酸枣根初生结构表皮细胞的厚度和宽度逐渐增加,皮层薄壁细胞的厚度和宽度、皮层薄壁细胞层数和皮层厚度均以宁夏银川样地的最大。酸枣根的次生结构包括周皮(木栓层、木栓形成层、栓内层)和次生维管组织(次生韧皮部、维管形成层和次生木质部)。从烟台至新疆吐鲁番随生境干旱加剧,酸枣植株根系周皮逐渐加厚、致密度提高。次生木质部中,导管的数量增加,管径增大。干旱环境中,酸枣植株根系结构上的变化一方面提高了吸水能力和输水效率,另一方面增强了保水能力,减少水分散失,这可能是其适应干旱逆境的机制之一。
Water and nutrition are mainly uptaken by the root system,and the root system is directly grown in the soil and is sensitive to stress. In arid environments,the structure of the root system could be changed to maintain normal biology function and adapt to stress conditions. To date,most of the studies have focused on the structure or morphology of root system responses to single stress factors. However,less attention has been concentrated on the adaptive mechanism of the entire root structure to different ecotopes. Therefore,this study explored the root morphological plasticity of Ziziphus jujuba var. spinosa in response to natural drought gradient ecotopes. Root samples were selected from Yantai-ShijiazhuangYinchuan-Turpan of China. The four ecotopes formed a natural drought gradient environment according to their soil moisture,annual precipitation,and humidity coefficients. The purpose of this study was to elucidate the mechanism of root plasticity response to different environments caused by climate change. The results showed that root primary structure of Ziziphus jujuba var. spinosa included the epidermis,cortex,and vascular cylinder. The epidermis is on the surface of the young root,which is constituted by a single layer of epidermis cells that are small and arranged closely. The cortex takes thegreatest proportion of the primary structure,and it is constituted by a larger quantity of parenchymal cells. The vascular cylinder is located in the innermost layer,and the cells are small and crowded together. It is composed of pericycle,primary xylem,primary phloem,and parenchymal cells. When drought aggravated,the thickness and width of the epidermis cells were increased. In addition,the thickness,width,and number of plies of parenchymal cells,and the thickness of the cortex were all largest at the Yinchuan ecotope. The root secondary structure of Ziziphus jujuba var. spinosa was divided into periderm(phellem layer,phellogen,phelloderm) and secondary vascular tissue(secondary phloem,vascular cambium,secondary xylem). As the drought intensified from Yantai to Turpan,the thickness and density of periderm was gradually increased. In addition,the diameter and quantity of vessels in secondary xylem were increased. These results illustrated that one of the adaptive mechanisms of plant to drought stress is the changes in the plasticity of root structure that enhance water uptake capacity and water transport efficiency. On the other hand,it improves water retaining capacity and decreases water desorption.
Water and nutrition are mainly uptaken by the root system,and the root system is directly grown in the soil and is sensitive to stress. In arid environments,the structure of the root system could be changed to maintain normal biology function and adapt to stress conditions. To date,most of the studies have focused on the structure or morphology of root system responses to single stress factors. However,less attention has been concentrated on the adaptive mechanism of the entire root structure to different ecotopes. Therefore,this study explored the root morphological plasticity of Ziziphus jujuba var. spinosa in response to natural drought gradient ecotopes. Root samples were selected from Yantai-ShijiazhuangYinchuan-Turpan of China. The four ecotopes formed a natural drought gradient environment according to their soil moisture,annual precipitation,and humidity coefficients. The purpose of this study was to elucidate the mechanism of root plasticity response to different environments caused by climate change. The results showed that root primary structure of Ziziphus jujuba var. spinosa included the epidermis,cortex,and vascular cylinder. The epidermis is on the surface of the young root,which is constituted by a single layer of epidermis cells that are small and arranged closely. The cortex takes thegreatest proportion of the primary structure,and it is constituted by a larger quantity of parenchymal cells. The vascular cylinder is located in the innermost layer,and the cells are small and crowded together. It is composed of pericycle,primary xylem,primary phloem,and parenchymal cells. When drought aggravated,the thickness and width of the epidermis cells were increased. In addition,the thickness,width,and number of plies of parenchymal cells,and the thickness of the cortex were all largest at the Yinchuan ecotope. The root secondary structure of Ziziphus jujuba var. spinosa was divided into periderm(phellem layer,phellogen,phelloderm) and secondary vascular tissue(secondary phloem,vascular cambium,secondary xylem). As the drought intensified from Yantai to Turpan,the thickness and density of periderm was gradually increased. In addition,the diameter and quantity of vessels in secondary xylem were increased. These results illustrated that one of the adaptive mechanisms of plant to drought stress is the changes in the plasticity of root structure that enhance water uptake capacity and water transport efficiency. On the other hand,it improves water retaining capacity and decreases water desorption.
引文
[1]朱广龙,邓荣华,马茵,魏学智.酸枣茎导管对自然梯度干旱生境响应的结构特征.生态学报,2015,35(24):8268-8275.
[2]弋良朋,马健,李彦.盐胁迫对3种荒漠盐生植物苗期根系特征及活力的影响.中国科学D辑地球科学,2006,36(S2):86-94.
[3]Schiefelbein J W,Benfey P N.The development of plant roots:new approaches to underground problems.The Plant Cell,1991,3(11):1147-1154.
[4]Merchan F,de Lorenzo L,Rizzo S G,Niebel A,Manyani H,Frugier F,Sousa C,Crespi M.Identification of regulatory pathways involved in the reacquisition of root growth after salt stress in Medicago truncatula.The Plant Journal,2007,51(1):1-17.
[5]Hodge A,Berta G,Doussan C,Merchan F,Crespi M.Plant root growth,architecture and function.Plant&Soil,2009,321(1/2):153-187.
[6]Macfall J S,Johnson G A,Kramer P J.Comparative water uptake by roots of different ages in seedlings of loblolly pine(Pinus taeda L.).New Phytologist,1991,119(4):551-560.
[7]Nobel P S.Physicochemical and Environmental Plant Physiology.4th ed.Amsterdam:Elsevier,2009.
[8]朱广龙,邓荣华,魏学智.酸枣叶表皮微形态对不同生态环境的适应特征.生态学报,2016,36(16):5193-5203.
[9]王慧莉,田涛,王建永,Batool A,赵旭喆,莫非,Akram N A,熊友才.旱区农业雨水资源利用与生态系统可持续性:2013干旱农业和生态系统可持续性国际会议综述.生态学杂志,2014,33(11):3127-3136.
[10]蔡雨晴,贾棹东,吴茜茜,白红进,蒋卉.响应面法优化野生酸枣仁中总黄酮的提取工艺.中国饲料,2016,(3):23-27.
[11]耿欣,李廷利.酸枣仁主要化学成分及药理作用研究进展.中医药学报,2016,44(5):84-86.
[12]吕新民,杨怡帆,鲁晓燕,靳娟,樊新民.Na Cl胁迫对酸枣幼苗As A-GSH循环的影响.植物生理学报,2016,52(5):736-744.
[13]邓荣华,高瑞如,刘后鑫,赵亚锦,朱广龙,魏学智.自然干旱梯度下的酸枣表型变异.生态学报,2016,36(10):2954-2961.
[14]王改利,魏忠,贺少轩,周雪洁,梁宗锁.土壤干旱胁迫对酸枣叶片黄酮类代谢及某些生长和生理指标的影响.植物资源与环境学报,2011,20(3):1-8.
[15]朱广龙,魏学智.酸枣叶片结构可塑性对自然梯度干旱生境的适应特征.生态学报,2016,36(19):6178-6187.
[16]朱广龙,马茵,韩蕾,霍张丽,魏学智.植物晶体的形态结构、生物功能及形成机制研究进展.生态学报,2014,34(22):6429-6439.
[17]赵祥,董宽虎,张垚,朱慧森,杨武德,杨美红.达乌里胡枝子根解剖结构与其抗旱性的关系.草地学报,2011,19(1):13-19.
[18]李正理,李荣敖.我国甘肃九种旱生植物同化枝的解剖观察.植物生态学报(英文版),1981,(3):15-19.
[19]黄振英,吴鸿,胡正海.30种新疆沙生植物的结构及其对沙漠环境的适应.植物生态学报,1997,21(6):521-530.
[20]白重炎,周迪.雀儿舌头根、茎、叶的解剖结构研究.安徽农业科学,2011,39(6):3336-3338,3379-3379.
[21]周智斌,李培军.我国旱生植物的形态解剖学研究.干旱区研究,2002,19(2):35-40.
[22]刘穆.种子植物形态解剖学导论(第五版).北京:科学出版社,2010.
[23]陈亚宁,杨思全.自然灾害的灰色关联灾情评估模型及应用研究.地理科学进展,1999,18(2):158-162.
[24]张艳馥,沙伟,王晓琦,杨柳,倪红伟.三江平原不同生境条件下小叶章根解剖结构的研究.中国草地学报,2006,28(5):110-112,117-117.
[25]张义玲,冯成强,孟繁蕴,张文生.药用柴胡属植物产地与化学成分相关性研究.生命科学研究专辑,2006,10(4):86-89.
[26]郑丽,蔡霞,胡正海.狭叶柴胡根的发育解剖学研究.植物研究,2009,29(6):659-664.
[27]张瑞群,马晓东,吕豪豪.多枝柽柳幼苗生长及其根系解剖结构对水盐胁迫的响应.草业科学,2016,33(6):1164-1173.
[2]弋良朋,马健,李彦.盐胁迫对3种荒漠盐生植物苗期根系特征及活力的影响.中国科学D辑地球科学,2006,36(S2):86-94.
[3]Schiefelbein J W,Benfey P N.The development of plant roots:new approaches to underground problems.The Plant Cell,1991,3(11):1147-1154.
[4]Merchan F,de Lorenzo L,Rizzo S G,Niebel A,Manyani H,Frugier F,Sousa C,Crespi M.Identification of regulatory pathways involved in the reacquisition of root growth after salt stress in Medicago truncatula.The Plant Journal,2007,51(1):1-17.
[5]Hodge A,Berta G,Doussan C,Merchan F,Crespi M.Plant root growth,architecture and function.Plant&Soil,2009,321(1/2):153-187.
[6]Macfall J S,Johnson G A,Kramer P J.Comparative water uptake by roots of different ages in seedlings of loblolly pine(Pinus taeda L.).New Phytologist,1991,119(4):551-560.
[7]Nobel P S.Physicochemical and Environmental Plant Physiology.4th ed.Amsterdam:Elsevier,2009.
[8]朱广龙,邓荣华,魏学智.酸枣叶表皮微形态对不同生态环境的适应特征.生态学报,2016,36(16):5193-5203.
[9]王慧莉,田涛,王建永,Batool A,赵旭喆,莫非,Akram N A,熊友才.旱区农业雨水资源利用与生态系统可持续性:2013干旱农业和生态系统可持续性国际会议综述.生态学杂志,2014,33(11):3127-3136.
[10]蔡雨晴,贾棹东,吴茜茜,白红进,蒋卉.响应面法优化野生酸枣仁中总黄酮的提取工艺.中国饲料,2016,(3):23-27.
[11]耿欣,李廷利.酸枣仁主要化学成分及药理作用研究进展.中医药学报,2016,44(5):84-86.
[12]吕新民,杨怡帆,鲁晓燕,靳娟,樊新民.Na Cl胁迫对酸枣幼苗As A-GSH循环的影响.植物生理学报,2016,52(5):736-744.
[13]邓荣华,高瑞如,刘后鑫,赵亚锦,朱广龙,魏学智.自然干旱梯度下的酸枣表型变异.生态学报,2016,36(10):2954-2961.
[14]王改利,魏忠,贺少轩,周雪洁,梁宗锁.土壤干旱胁迫对酸枣叶片黄酮类代谢及某些生长和生理指标的影响.植物资源与环境学报,2011,20(3):1-8.
[15]朱广龙,魏学智.酸枣叶片结构可塑性对自然梯度干旱生境的适应特征.生态学报,2016,36(19):6178-6187.
[16]朱广龙,马茵,韩蕾,霍张丽,魏学智.植物晶体的形态结构、生物功能及形成机制研究进展.生态学报,2014,34(22):6429-6439.
[17]赵祥,董宽虎,张垚,朱慧森,杨武德,杨美红.达乌里胡枝子根解剖结构与其抗旱性的关系.草地学报,2011,19(1):13-19.
[18]李正理,李荣敖.我国甘肃九种旱生植物同化枝的解剖观察.植物生态学报(英文版),1981,(3):15-19.
[19]黄振英,吴鸿,胡正海.30种新疆沙生植物的结构及其对沙漠环境的适应.植物生态学报,1997,21(6):521-530.
[20]白重炎,周迪.雀儿舌头根、茎、叶的解剖结构研究.安徽农业科学,2011,39(6):3336-3338,3379-3379.
[21]周智斌,李培军.我国旱生植物的形态解剖学研究.干旱区研究,2002,19(2):35-40.
[22]刘穆.种子植物形态解剖学导论(第五版).北京:科学出版社,2010.
[23]陈亚宁,杨思全.自然灾害的灰色关联灾情评估模型及应用研究.地理科学进展,1999,18(2):158-162.
[24]张艳馥,沙伟,王晓琦,杨柳,倪红伟.三江平原不同生境条件下小叶章根解剖结构的研究.中国草地学报,2006,28(5):110-112,117-117.
[25]张义玲,冯成强,孟繁蕴,张文生.药用柴胡属植物产地与化学成分相关性研究.生命科学研究专辑,2006,10(4):86-89.
[26]郑丽,蔡霞,胡正海.狭叶柴胡根的发育解剖学研究.植物研究,2009,29(6):659-664.
[27]张瑞群,马晓东,吕豪豪.多枝柽柳幼苗生长及其根系解剖结构对水盐胁迫的响应.草业科学,2016,33(6):1164-1173.