秦岭羽枝青藓生长的关键影响因子

Key factors influencing the growth of Brachythecium plumosum in Qinling Mountains

利用苔藓植物开展裸岩工程创面生态修复是一条低成本、高效益的潜在新途径,巨量苔藓种源的供给是实现这种新措施工程化应用的根本前提,而掌握特定藓种生长的发育特征及关键影响因子则是实现这一目标的首要任务。以秦岭地区石生优势藓种——羽枝青藓(Brachythecium plumosum)为研究对象,利用野外原位观测、室内组织培养及养分施加试验,通过观测生长指标(主茎长、覆盖面积、分枝长和分枝数)和形态变化,了解其自然发育特征和不同繁殖体类型及养分供给模式对其生长发育的影响。结果表明:(1)羽枝青藓通过特有的形态特征适应岩石表层环境。主茎生长时,其侧边分枝同步发育、且表现的较为密集。(2)微生境显著影响羽枝青藓发育。与冠层间相比,冠层下除光照强度降低幅度较大外(15%—55%),空气湿度、温度的变化幅度较小,但羽枝青藓的生长速率提高3倍以上。(3)羽枝青藓的茎和叶片都有发育为配子体的潜力,但茎的再生能力优于叶片,且二者的发育模式不同。接种茎的成活率达到100%,配子体由茎直接再生,发育的原丝体未分化,主要发挥定殖和养分吸收的作用;叶片的成活率仅3.3%,发育过程中先产生原丝体,再分化为配子体。(4)长期营养液供给可能对岩石表层的苔藓生长产生负面影响。Hoagland营养液在试验前期促进了羽枝青藓生长,但也加剧了致病菌和藻类发育,导致后期羽枝青藓发黄枯萎。总的来看:羽枝青藓对逆境有较强的适应性,对微环境变化敏感,周围生长条件适宜时可快速向外扩张。不同的繁殖体和营养液供给模式都会对羽枝青藓的生长产生显著影响。开展羽枝青藓种源扩繁生产时应充分借鉴这些研究结果。

Using bryophytes for ecological restoration of bare rock engineering wound surfaces is an inexpensive,high⁃benefit,and potentially novel method.The key to realizing the engineering application of this new measure is a vast supply of moss inoculum.Mastering the developmental characteristics and important influencing elements of the specific moss species is the main objective of accomplishing this goal.Therefore,a study was carried out on Brachythecium plumosum,a dominant moss species on the rock surface in Qinling Mountains,to understand the natural developmental characteristics,the effects of different propagule types,and nutrient supply patterns on the growth and development of the moss by observing the growth index(stem length,branch length,cover area,and number of branch)and morphological changes.Field observations(in situ),indoor tissue culture,and nutrient application tests were used.The results showed that:(1)The unique morphological traits of Brachythecium plumosum allowed it to adapt to the rocky habitat.Brachythecium plumosum had densely lateral branches that formed simultaneously with the growth of the stem.(2)Microhabitats significantly influenced the development of the Brachythecium plumosum.Except a significant reduction in light intensity(15—55%),the undercanopy showed less variation in air humidity and temperature of the rock surface than the intercanopy.However,the growth rate of Brachythecium plumosum was more than 3 times higher under the canopy than in the intercanopy.(3)Both stems and leaves of Brachythecium plumosum had the potential to develop into gametophytes,but the development patterns were different and stems had a better capacity for regeneration than leaves.The gametophytes were regenerated directly from the stems,which had 100%survival rate.The developing protonema was not differentiated,which might play a role in attachment on the rock surface and nutrient uptake.Only 3.3%of the leaves survived,and the gametophytes differentiated from the protonema.(4)Long⁃term nutrient solution supply might have a negative impact on the moss growth on the rock surface.In the early stages of the experiment,the Hoagland nutrient solution promoted the growth of Brachythecium plumosum while simultaneously encouraging the development of pathogenic bacteria/pathomycete and algae,which caused the moss to wither or turn yellow.In sum,Brachythecium plumosum expanded quickly when the environmental conditions were suitable,which had good adaptability to adversity and was sensitive to microenvironmental changes.The development of Brachythecium plumosum was significantly influenced by the propagule types and nutrient supply patterns.These results offer an invaluable reference for the Brachythecium plumosum inoculum artificial propagation technique and ought to be completely considered in subsequent applications and studies.