本文主要研究内容
作者瞿欢欢（2019）在《毛竹扩张对桫椤根系形态可塑性及根际反硝化细菌群落结构的影响》一文中研究指出：桫椤(Alsophila spinulosa)为桫椤科(Cyatheaceae)桫椤属(Alsophila)植物,它不仅是地球历史变迁的见证,也是科学研究的活化石,在研究植物起源、进化和地理区系等方面有着举足轻重的作用。桫椤现已处于濒危状态,被列为国家二级重点保护野生植物,气候的变化及生境的破坏致其数量急剧减少。赤水桫椤国家级自然保护区以桫椤及其生存环境为主要保护对象,保护区内共有桫椤四万余株,为世界上拥有桫椤数量最多、面积最广的林区之一。保护区内采伐的禁止使得毛竹大量扩张,迅速入侵到桫椤林中,桫椤生长的原生境受到了不同程度的破坏,原有的桫椤纯林近年来已不复存在。从竞争干扰的角度来看,植物地下部分的竞争比地上部分更为激烈。研究表明,毛竹在与针阔树的地下竞争中会通过增加根系生物量密度、细根比根长,降低相邻同级侧根节点距的策略来占据竞争优势。同时,入侵种的扩张会改变土壤养分循环及根际土壤微生物的群落结构,促进微生物群落的功能发挥,从而创造对自身有利的土壤微环境,加速其入侵进程。本文以赤水桫椤国家级自然保护区内受毛竹(Phyllostachys heterocycla)不同程度干扰的桫椤群落为研究对象,采用根钻法分别研究了水平和垂直方向上的毛竹、桫椤根系形态可塑性变化。又依据根际微生物与植物根系相互作用的原理,采用高通量测序技术,对受毛竹轻度、中度、重度干扰的桫椤根际土壤qnorB型反硝化细菌群落结构及多样性进行了分析,以期从地下微生态角度为桫椤种群的保护提供理论依据。具体研究结果如下:(1)毛竹、桫椤根系垂直方向的分布格局显示,随干扰强度的增大毛竹总根系生物量密度显著增加,桫椤根系则呈先增加后减少的趋势;0-10 cm土层毛竹根系生物量密度最大,为951.95 g/m~2,占总量的39.09%;直径>5 mm的毛竹根系仅分布在重度干扰的10-20 cm土层中;随土层深度的增加桫椤总根系生物量密度逐渐增加,即桫椤根系多集中分布于20-30 cm土层。(2)各干扰程度下毛竹周围各径级的桫椤根系生物量密度均远低于毛竹根系,≤2 mm的毛竹根系在3个土层中均随着离竹距离的增加而逐渐减少,2-5 mm根系水平方向上总体变化同≤2 mm根系;毛竹周围的桫椤根系总生物量随干扰程度的增加而逐渐减少,但其随着离竹距离的增加而逐渐增多。各样地桫椤周围的毛竹根系在离桫椤60 cm处最多,随着干扰程度的增加毛竹总根系生物量密度逐渐增大。桫椤根系在3个土壤层次中均表现为离桫椤20 cm处最高,40 cm处次之,离桫椤较远的60 cm处最低。(3)重度干扰下的毛竹细根比根长较轻度和中度干扰显著增加,平均增幅为66.9%。桫椤细根比根长在10-20 cm土层中先升高后降低,在其余土层中的桫椤细根比根长则逐渐降低,总体上,重度干扰下桫椤细根比根长较轻度干扰下降了28.71%。在三个土层中毛竹一级侧根节点距均随干扰程度的增强而减小,二级侧根节点距在10-20 cm土层中变化趋势同一级侧根,在其余土层中均先增加后减少。总体来看,毛竹一、二级侧根节点距在重度干扰下最小,且在各干扰程度下均表现为表层土壤中节点距最小,侧根数目最多。(4)随毛竹干扰程度的增强,土壤碱解氮含量显著增加,速效磷含量显著降低(P<0.05),pH、含水量及土壤有机质均无显著变化。(5)高通量测序结果显示,3个不同干扰程度下桫椤根际土壤样品共获得有效序列201641条,优化序列119600条;鉴定出的qnorB型反硝化细菌有4-5门,11-13纲,19-20目,23-25科,25-28属,33-37种,其中轻度干扰下反硝化细菌组成最少,重度干扰下细菌种类最为丰富。(6)希瓦氏菌属(Shewanella)在各样地中的丰度均大于6.5%,为优势菌群,除厌氧粘细菌属(Anaeromyxobacter)外,其余属的群落丰度均随着干扰强度的增加而呈上升趋势。受毛竹中度和重度干扰的样地具有更高的Ace和Chao值;重度干扰下的qnorB型反硝化细菌群落具有最高的Shannon指数值及最低的Simpson指数值。UPGMA和PCoA分析均显示,重度干扰下的qnorB型反硝化细菌群落与轻度干扰下的分属于两个不同的分支。根据本研究得出的结果,并结合保护区的实际情况,提出以下保护对策:(1)保护区应加强对毛竹扩张的GPS遥感监控,实时了解、监测毛竹扩张的状态及桫椤种群的变化;(2)在受毛竹中度及重度干扰的桫椤群落中及时、适度间伐毛竹,避免毛竹进一步侵占桫椤的生长地;(3)应加强人工孢子繁育及组织培养方面的研究,在受到毛竹干扰严重的群落中适当栽植桫椤幼苗。
Abstract
suo luo (Alsophila spinulosa)wei suo luo ke (Cyatheaceae)suo luo shu (Alsophila)zhi wu ,ta bu jin shi de qiu li shi bian qian de jian zheng ,ye shi ke xue yan jiu de huo hua dan ,zai yan jiu zhi wu qi yuan 、jin hua he de li ou ji deng fang mian you zhao ju zu qing chong de zuo yong 。suo luo xian yi chu yu bin wei zhuang tai ,bei lie wei guo jia er ji chong dian bao hu ye sheng zhi wu ,qi hou de bian hua ji sheng jing de po huai zhi ji shu liang ji ju jian shao 。chi shui suo luo guo jia ji zi ran bao hu ou yi suo luo ji ji sheng cun huan jing wei zhu yao bao hu dui xiang ,bao hu ou nei gong you suo luo si mo yu zhu ,wei shi jie shang yong you suo luo shu liang zui duo 、mian ji zui an de lin ou zhi yi 。bao hu ou nei cai fa de jin zhi shi de mao zhu da liang kuo zhang ,xun su ru qin dao suo luo lin zhong ,suo luo sheng chang de yuan sheng jing shou dao le bu tong cheng du de po huai ,yuan you de suo luo chun lin jin nian lai yi bu fu cun zai 。cong jing zheng gan rao de jiao du lai kan ,zhi wu de xia bu fen de jing zheng bi de shang bu fen geng wei ji lie 。yan jiu biao ming ,mao zhu zai yu zhen kuo shu de de xia jing zheng zhong hui tong guo zeng jia gen ji sheng wu liang mi du 、xi gen bi gen chang ,jiang di xiang lin tong ji ce gen jie dian ju de ce lve lai zhan ju jing zheng you shi 。tong shi ,ru qin chong de kuo zhang hui gai bian tu rang yang fen xun huan ji gen ji tu rang wei sheng wu de qun la jie gou ,cu jin wei sheng wu qun la de gong neng fa hui ,cong er chuang zao dui zi shen you li de tu rang wei huan jing ,jia su ji ru qin jin cheng 。ben wen yi chi shui suo luo guo jia ji zi ran bao hu ou nei shou mao zhu (Phyllostachys heterocycla)bu tong cheng du gan rao de suo luo qun la wei yan jiu dui xiang ,cai yong gen zuan fa fen bie yan jiu le shui ping he chui zhi fang xiang shang de mao zhu 、suo luo gen ji xing tai ke su xing bian hua 。you yi ju gen ji wei sheng wu yu zhi wu gen ji xiang hu zuo yong de yuan li ,cai yong gao tong liang ce xu ji shu ,dui shou mao zhu qing du 、zhong du 、chong du gan rao de suo luo gen ji tu rang qnorBxing fan xiao hua xi jun qun la jie gou ji duo yang xing jin hang le fen xi ,yi ji cong de xia wei sheng tai jiao du wei suo luo chong qun de bao hu di gong li lun yi ju 。ju ti yan jiu jie guo ru xia :(1)mao zhu 、suo luo gen ji chui zhi fang xiang de fen bu ge ju xian shi ,sui gan rao jiang du de zeng da mao zhu zong gen ji sheng wu liang mi du xian zhe zeng jia ,suo luo gen ji ze cheng xian zeng jia hou jian shao de qu shi ;0-10 cmtu ceng mao zhu gen ji sheng wu liang mi du zui da ,wei 951.95 g/m~2,zhan zong liang de 39.09%;zhi jing >5 mmde mao zhu gen ji jin fen bu zai chong du gan rao de 10-20 cmtu ceng zhong ;sui tu ceng shen du de zeng jia suo luo zong gen ji sheng wu liang mi du zhu jian zeng jia ,ji suo luo gen ji duo ji zhong fen bu yu 20-30 cmtu ceng 。(2)ge gan rao cheng du xia mao zhu zhou wei ge jing ji de suo luo gen ji sheng wu liang mi du jun yuan di yu mao zhu gen ji ,≤2 mmde mao zhu gen ji zai 3ge tu ceng zhong jun sui zhao li zhu ju li de zeng jia er zhu jian jian shao ,2-5 mmgen ji shui ping fang xiang shang zong ti bian hua tong ≤2 mmgen ji ;mao zhu zhou wei de suo luo gen ji zong sheng wu liang sui gan rao cheng du de zeng jia er zhu jian jian shao ,dan ji sui zhao li zhu ju li de zeng jia er zhu jian zeng duo 。ge yang de suo luo zhou wei de mao zhu gen ji zai li suo luo 60 cmchu zui duo ,sui zhao gan rao cheng du de zeng jia mao zhu zong gen ji sheng wu liang mi du zhu jian zeng da 。suo luo gen ji zai 3ge tu rang ceng ci zhong jun biao xian wei li suo luo 20 cmchu zui gao ,40 cmchu ci zhi ,li suo luo jiao yuan de 60 cmchu zui di 。(3)chong du gan rao xia de mao zhu xi gen bi gen chang jiao qing du he zhong du gan rao xian zhe zeng jia ,ping jun zeng fu wei 66.9%。suo luo xi gen bi gen chang zai 10-20 cmtu ceng zhong xian sheng gao hou jiang di ,zai ji yu tu ceng zhong de suo luo xi gen bi gen chang ze zhu jian jiang di ,zong ti shang ,chong du gan rao xia suo luo xi gen bi gen chang jiao qing du gan rao xia jiang le 28.71%。zai san ge tu ceng zhong mao zhu yi ji ce gen jie dian ju jun sui gan rao cheng du de zeng jiang er jian xiao ,er ji ce gen jie dian ju zai 10-20 cmtu ceng zhong bian hua qu shi tong yi ji ce gen ,zai ji yu tu ceng zhong jun xian zeng jia hou jian shao 。zong ti lai kan ,mao zhu yi 、er ji ce gen jie dian ju zai chong du gan rao xia zui xiao ,ju zai ge gan rao cheng du xia jun biao xian wei biao ceng tu rang zhong jie dian ju zui xiao ,ce gen shu mu zui duo 。(4)sui mao zhu gan rao cheng du de zeng jiang ,tu rang jian jie dan han liang xian zhe zeng jia ,su xiao lin han liang xian zhe jiang di (P<0.05),pH、han shui liang ji tu rang you ji zhi jun mo xian zhe bian hua 。(5)gao tong liang ce xu jie guo xian shi ,3ge bu tong gan rao cheng du xia suo luo gen ji tu rang yang pin gong huo de you xiao xu lie 201641tiao ,you hua xu lie 119600tiao ;jian ding chu de qnorBxing fan xiao hua xi jun you 4-5men ,11-13gang ,19-20mu ,23-25ke ,25-28shu ,33-37chong ,ji zhong qing du gan rao xia fan xiao hua xi jun zu cheng zui shao ,chong du gan rao xia xi jun chong lei zui wei feng fu 。(6)xi wa shi jun shu (Shewanella)zai ge yang de zhong de feng du jun da yu 6.5%,wei you shi jun qun ,chu ya yang nian xi jun shu (Anaeromyxobacter)wai ,ji yu shu de qun la feng du jun sui zhao gan rao jiang du de zeng jia er cheng shang sheng qu shi 。shou mao zhu zhong du he chong du gan rao de yang de ju you geng gao de Acehe Chaozhi ;chong du gan rao xia de qnorBxing fan xiao hua xi jun qun la ju you zui gao de Shannonzhi shu zhi ji zui di de Simpsonzhi shu zhi 。UPGMAhe PCoAfen xi jun xian shi ,chong du gan rao xia de qnorBxing fan xiao hua xi jun qun la yu qing du gan rao xia de fen shu yu liang ge bu tong de fen zhi 。gen ju ben yan jiu de chu de jie guo ,bing jie ge bao hu ou de shi ji qing kuang ,di chu yi xia bao hu dui ce :(1)bao hu ou ying jia jiang dui mao zhu kuo zhang de GPSyao gan jian kong ,shi shi le jie 、jian ce mao zhu kuo zhang de zhuang tai ji suo luo chong qun de bian hua ;(2)zai shou mao zhu zhong du ji chong du gan rao de suo luo qun la zhong ji shi 、kuo du jian fa mao zhu ,bi mian mao zhu jin yi bu qin zhan suo luo de sheng chang de ;(3)ying jia jiang ren gong bao zi fan yo ji zu zhi pei yang fang mian de yan jiu ,zai shou dao mao zhu gan rao yan chong de qun la zhong kuo dang zai zhi suo luo you miao 。
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论文作者分别是来自西南大学的瞿欢欢，发表于刊物西南大学2019-09-24论文，是一篇关于毛竹论文,桫椤论文,根系论文,形态可塑性论文,型反硝化细菌论文,西南大学2019-09-24论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自西南大学2019-09-24论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。