摘要
【目的】马尾松(Pinus massoniana)是我国人工林的重要组成树种,对酸沉降高度敏感。随着我国大气酸沉降的日趋严重,马尾松林出现针尖坏死,树枝枯萎,甚至死亡等受害症状。木本植物响应酸沉降根系生理变化过程的研究相对较少,酸沉降对马尾松根系生理特性的影响仍不清楚。笔者研究马尾松幼苗根系生理指标在不同酸沉降强度和时间下的变化,探究马尾松根系对大气酸沉降的适应能力。【方法】以南京老山林场林地0~20 cm混合土壤为培养基质,土培100 d长势一致的马尾松幼苗为试验材料,调节pH 6.5模拟雨水为对照,配制化学组分类似于自然降水的模拟酸雨,其pH设置为5.6(微酸化处理)、4.5(轻度酸处理)、3.5(中度酸处理)和2.5(重度酸处理),按2017年5—8月南京市实际降水量、时间和频率对栽培马尾松幼苗喷淋处理。在栽培30、60和100 d时测定幼苗根系各生理指标,采用TTC还原分光光度法测定根系活力,甲烯蓝吸附法测定吸收面积,电导率法测定质膜透性,加速溶剂萃取(accelerated solvent extraction ASE)-固相萃取(solid-phase extraction,SPE)-高效液相色谱(HPLC)-电喷雾电离(electrosprag ionization,ESI)-串联质谱(MS/MS)法测定根系超痕量有机酸,复合电极法测定根际土壤pH。用SPSS 20.0软件处理数据,用One-Way ANOVA进行单因素方差分析,用Bivariate correlations进行相关性分析。【结果】随模拟酸雨pH的下降,马尾松幼苗根系活力、根系总吸收面积、活跃吸收面积、苹果酸与柠檬酸分泌量均呈现先升高后降低的趋势,在轻度酸处理下达最高值,中、重度酸处理下各指标显著降低;随酸雨喷淋时间推移,差异越明显,重度酸处理100 d的上述根系各生理指标相比于栽培初期(30 d)分别下降了(46.25±7.23)%、(56.37±8.14)%、(38.55±11.58)%、(68.45±5.41)%和(10.80±4.93)%。而马尾松幼苗根系质膜透性的变化趋势则相反,随模拟酸雨
【Objective】Pinus massoniana is an important plantation species in China,it is highly sensitive to acid deposition.As atmospheric acid deposition has increased,symptoms of injury,such as needle tip necrosis,branch withering,and even death,have been observed in P.massoniana forests.However,there are relatively few studies assessing changes in root physiological processes in forest woody plants in response to acid deposition.Moreover,the effects of acid deposition on the physiological characteristics of P.massoniana roots are still unknown.We focused on the changes in root physiological parameters of P.massoniana seedlings exposed to simulated acid rain(with different acidity levels and treatment times)and studied the adaptability of the species to atmospheric acid deposition.【Method】Woodland mixed soil from Nanjing Laoshan Forest Farm(Nanjing,Jiangsu Province)was collected at a depth of 0-20 cm and used as the culture matrix.After 100 days of soil culture,P.massoniana seedlings receiving the same growth conditions were selected as the experimental material.The chemical components of the simulated acid rain were similar to those of natural precipitation,and the acidity was set as follows:pH 6.5(control),pH 5.6(micro acid treatment),pH 4.5(mild acid treatment),pH 3.5(moderate acid treatment),and pH 2.5(severe acid treatment).The spray amount,time and frequency of simulated acid rain were set according to the precipitation status of Nanjing from May to August 2017.The root physiological parameters of P.massoniana seedlings were measured on treatment days 30,60 and 100.Root activity was determined by triphenyl tetrazolium chloride-reduction spectrophotometry,the root absorbing area was determined via methylene blue adsorption,the relative permeability of roots plasma membrane was determined using the conductivity method,and ultra-trace organic acids were determined by combining accelerated solvent extraction and solid-phase extraction liquid chromatography with electrospray ionization tandem mass spectrometry.T
作者
周思婕
王平
张敏
陈舒展
许雯
朱丽婷
何销勤
龚书锐
ZHOU Sijie;WANG Ping;ZHANG Min;CHEN Shuzhan;XU Wen;ZHU Liting;HE Xiaoqin;GONG Shurui(College of Biology and the Environment,Nanjing Forestry University,Nanjing 210037,China)
出处
《南京林业大学学报（自然科学版）》
CAS
CSCD
北大核心
2020年第4期111-118,共8页
Journal of Nanjing Forestry University：Natural Sciences Edition
基金
国家自然科学基金项目(30771696,31270680)。
关键词
酸沉降污染
马尾松幼苗
根系生理特性
有机酸分泌
根际土壤
根系活力
acid deposition contamination
Pinus massoniana(masson pine)seedling
root physiological characteristic
organic acid secretion
rhizospheric soil
root activity
