淹水对菖蒲(Acorus calamus)根际氧环境的影响  

Impacts of Rhizosphere Oxygen Environment at Seedling and Adult Plant Stages of Acorus calamus in Response to Flooding Stress

作　　者：王文林[1,2] 韩睿明[2] 王国祥[2] 唐晓燕[1] 夏劲[2] 梁斌[1] 李维新[1] 

机构地区：[1]环境保护部南京环境科学研究所,江苏南京210042 [2]南京师范大学地理科学学院,江苏省环境演变与生态建设重点实验室,江苏南京210023

出　　处：《环境科学研究》2015年第2期318-325,共8页Research of Environmental Sciences

基　　金：国家水体污染控制与治理科技重大专项(2012ZX07506-007);国家环境保护公益性行业科研专项(20130935);国家自然科学基金项目(41173078)

摘　　要：为研究淹水对湿地植物根际氧环境的影响,选择典型湿地植物菖蒲幼苗(株高约15 cm、根长约6 cm)和成株(株高约40cm、根长约11 cm)在沉积物中培养并完全淹没,利用微型电机控制氧气微光极对菖蒲根中部根际氧浓度及组织内部氧浓度原位测定3周.结果表明:短期(7 d)淹水,菖蒲幼苗及成株根际氧扩散层厚度及氧浓度比对照组均显著下降;在淹水第14天,在幼苗根际未检出氧扩散层;在淹水第21天,成株根际氧扩散层厚度及平均氧浓度仍分别为0.34 mm和11.18%,并保持至淹水试验结束.淹水组菖蒲的根际氧扩散层厚度、平均氧浓度均随根组织内部氧浓度的下降而降低,其中幼苗3个指标分别由初始的0.22 mm、1.4%和50.3%降至0 mm、0%和32.9%,成株分别由0.64 mm、19.3%和64.6%降至0.34 mm、11.2%和55.3%,表明前2个指标的下降程度显著超过后者;淹水组菖蒲幼苗、成株根组织内部氧浓度主要受植株光合作用的影响,而对照组则受光合作用及气体交换作用的共同影响,淹水能在短期(7 d)内促进菖蒲成株根通气组织的发育,使其孔隙率从28.45%升至32.44%,并有助于维持根组织内的氧浓度水平,根组织内部氧浓度淹水组(65.6%)与对照组(67.1%)无显著差异.研究表明,淹水胁迫下,根组织内部氧浓度水平是影响菖蒲根氧扩散的核心因素,其中幼苗根组织内部氧浓度显著下降并威胁到自身存活时,其已无氧扩散效应,而成株根组织内部较高的氧浓度使其仍能保持一定程度的氧扩散.To understand the impacts of rhizosphere oxygen environment in wetland plants in response to flooding stress,a typical wetland plant,Acorus calamus,was selected to study its rhizosphere oxygen characteristics in response to flooding stress.Young seedlings of height around 15 cm and adults plants of height 40 cm were cultivated in sediments and flooded completely.Rhizosphere oxygen profiles at the middle part of the whole root and inside the root axis were measured using a micromotor-controlled oxygen micro optode for 3 weeks.The results showed that at day 7 of the flooding period,both young seedlings and adult plants demonstrated a great reduction of thickness in the rhizosphere oxygen diffusive layer,while at day 14 of the flooding period,rhizosphere oxygen diffusion in young seedlings totally disappeared while that in the adult plants was partially maintained,and at day 21 of the flooding period,the thickness of oxygen diffusive layer in adult plants was 0.34 mm and the oxygen saturation rate was 11.18%.The thickness of oxygen diffusive layer and the average oxygen saturation rate in flood-treated young seedlings and adult plants significantly declined,in comparison to the declining root endogenous oxygen concentration with an even greater decrease rate.At the end of the experimental period,the three parameters mentioned above in flooded young seedlings decreased from 0.22 mm,1.4% and 50.3% to 0 mm,0% and 32.9%,while those in adult plants decreased from 0.64 mm,19.3% and 64.6% to 0.34 mm,11.2% and 55.3%,respectively.The root endogenous oxygen concentrations in both young and adult flooded seedlings were mainly affected by the photosynthetic rate,however,those in the control plants were affected by the photosynthetic capacity and gas exchange comprehensively.A short-term flooding stress of seven days could stimulate the development of aerenchyma in the root of A.calamus,which increased the root porosity from 28.45% to32.44% and was beneficial to maintaining the root endogenous oxygen concentration,which had no s

关 键 词：淹水 菖蒲幼苗 菖蒲成株 根际氧环境 

分 类 号：X171[环境科学与工程—环境科学]