长苞香蒲对人工盐碱湿地Na+和K+的吸收与转运特征

Characteristics of Na+ and K+ absorption and transport of Typha domingensis in artificial saline wetlands

关键词:  长苞香蒲, Na⁺和 K⁺含量, 脱盐作用, 转运特征, 植物修复

Key words:   Typha domingensis, Na⁺ and K⁺ contents, desalination, transport characteristics, plant remediation

摘要:

为揭示长苞香蒲(Typha domingensis)对盐生湿地生态系统中Na⁺和K⁺的吸收与转运特征,探讨长苞香蒲对盐生湿地的生态修复效果,该研究采用人工模拟盐生湿地的方法,设置CK(对照)、T1(浇灌100 mmol·L^-1盐水)、T2(浇灌200 mmol·L^-1盐水)及T3(浇灌300 mmol·L^-1盐水)4种不同盐浓度的人工湿地生态系统,并分别于5月5日(开始盐胁迫处理,S0)、5月30日(S1)、6月30日(S2)和7月30日(S3)测量其株高和干重、植株地上与地下部分Na⁺和K⁺的含量以及底泥和水体中Na⁺和K⁺的含量以分析长苞香蒲对盐碱湿地的脱盐作用。结果表明:(1)各处理的长苞香蒲的株高和干重随着处理时间的延长呈增加趋势,但与CK 相比,各处理生长量随盐浓度升高出现下降趋势。(2)高浓度盐处理(T3)使长苞香蒲的地上部分和地下部分的Na⁺分别增加了2.56倍和1.75倍,地上部分及地下部分的K⁺含量分别降低了34.1%和35.8%。(3)地上部分和地下部分的Na⁺/K⁺在处理和对照间均随处理时间延长呈增加的趋势,选择性转移系数与Na⁺和K⁺转移系数总体随处理时间延长呈降低的趋势。(4)在S0至S3期间,长苞香蒲对处理组土壤Na⁺和K⁺的去除率为10.6%～15.8%和2.3%～12.8%,对处理组水体Na⁺和K⁺的去除率为55.0%～65.1%和1.6%～67.0%。综上表明,盐胁迫能影响长苞香蒲体内的Na⁺和 K⁺平衡,长苞香蒲能够有效地吸收Na⁺,并在一定盐浓度下能通过K⁺的交换将Na⁺从根部吸收转运至地上部分。因此,长苞香蒲可通过离子转运的形式完成对盐离子的吸收,可作为盐碱湿地生态修复的优良植物。

Abstract:

In order to reveal the characteristics of both Na⁺ and K⁺ absorption and transport in Typha domingensis distribution in a wetland system, and to investigate the remediation effect of T. domingensis planting in the saline wetland, artificial saline wetlands with four different salinity concentrations were adopted in this experiment, namely CK(irrigation with tap water), T1(irrigation with 100 mmol·L^-1 saline water), T2(irrigation with 200 mmol·L^-1 saline water), and T3(irrigation with 300 mmol·L^-1 saline water), the height, dry weight, contents of Na⁺ and K⁺ in aboveground part and belowground part of the seedlings, as well as contents of Na⁺ and K⁺ in the water body and sediment. The effects of wetland salinity on the balance of Na⁺ and K⁺ in T. domingensis and its Na⁺ transport characteristics were analyzed via the variation in Na⁺/K⁺ and the former's Na⁺/K⁺ transfer factor under different treatments in different periods. The removal ratios of Na⁺ and K⁺ from soil and water body were calculated to analyze the desalination of wetlands by T. domingensis. The results were as follows:(1)The plant height and dry weight increase of T. domingensis in each treatment showed an increasing trend during the whole treatment stage, but the height of T. domingensis in different treatments were lower than that of CK.(2)The concentrations of Na⁺ in the aboveground and underground parts of T. domingensis were 2.56 times and 1.75 times of the CK, respectively, and the concentrations of K⁺ in the aboveground and belowground parts were decreased by 34.1% and 35.8%.(3)The value of Na⁺/K⁺ in the aboveground and underground parts showed an increasing trend during the whole experimental stage, and the selective transfer coefficient and the Na⁺ and K⁺ transfer coefficients generally showed a decreasing trend during the whole experimental stage.(4)The removal rates of Na⁺ and K⁺ in the soil of the treatment group by T. domingensis were 10.6%-15.8% and 2.3%-12.8%, the removal rates of Na⁺ and K⁺ in the water body of the treatment group were 55.0%-65.1% and 1.6%-67.0%. All the above results indicate that salt stress can affect the balance of Na⁺ and K⁺ in T. domingensis. Na⁺ can be effectively absorbed by T. domingensis, and Na⁺ can be transferred from the belowground part to the aboveground part by exchange with K⁺ in the plant. Therefore, the salt can be absorbed and transferred from the wetland system into the organ of T. domingensis by the mean of ion transport, which can be used as an excellent plant for saline wetland restoration.