酸沉降類型和噴施方式對木荷和濕地松幼苗生理生態(tài)及生長的影響
發(fā)布時間：2018-08-20 15:47
【摘要】：酸沉降是目前和將來影響人類福祉的重大環(huán)境問題之一,已引起國內(nèi)外學(xué)者的廣泛關(guān)注。我國南方是繼歐美之后的世界第三大酸沉降區(qū),地處長江三角洲的浙江省酸沉降尤為嚴(yán)重。酸沉降威脅著森林生態(tài)系統(tǒng)健康,導(dǎo)致林冠稀疏,土壤酸化,甚至造成森林衰退。由于生態(tài)系統(tǒng)類型、土壤狀況、酸沉降強(qiáng)度、類型和持續(xù)時間等不同,酸沉降對森林生態(tài)系統(tǒng)的影響存在很大差異。因此,了解大氣酸沉降特征及其對亞熱帶常見樹種生理生態(tài)和生長的綜合影響顯得尤為迫切。鑒于此,我們以浙江天童森林生態(tài)系統(tǒng)國家野外科學(xué)觀測研究站為基地,于2010年3月至2011年2月對大氣濕性酸沉降進(jìn)行監(jiān)測,研究降水酸度和離子組成的動態(tài)變化規(guī)律。同時,以一年生木荷(Schima superba)和濕地松(Pinus elliottii)幼苗為對象,研究不同酸度(pH 3.5和pH 2.5)、酸沉降類型(SO42-:NO3-分別為8：1和0.7：1)和噴施方式(葉面噴施和土壤灌溉)對幼苗生理生態(tài)及生長的影響,并結(jié)合土壤化學(xué)性質(zhì)分析,探討植物對酸沉降的綜合響應(yīng)機(jī)理以及導(dǎo)致該森林生態(tài)系統(tǒng)衰退的關(guān)鍵因素,以期為酸沉降危害嚴(yán)重地區(qū)森林生態(tài)系統(tǒng)恢復(fù)提供理論依據(jù)。研究所取得的主要結(jié)果如下：1)天童大氣降水酸化程度非常高,雨量加權(quán)平均pH值為4.37,酸雨發(fā)生率達(dá)93.6%。大氣降水中陰、陽離子加權(quán)平均濃度分別為140.7μeq·L-1和158.9μeq·L-1,具有明顯的季節(jié)變化規(guī)律,冬春季污染顯著高于夏秋季。降水中陰離子以S042-和N03-為主,陽離子以NH4+和Ca2+為主,SO42-/NO3-當(dāng)量比由15年前的4.32—6.42逐漸下降到1.9,說明該地區(qū)酸沉降類型由硫酸型向硫酸硝酸復(fù)合型轉(zhuǎn)變。海鹽對天童大氣降水離子組分有一定貢獻(xiàn),但對酸度的影響并不顯著。2)重度酸沉降處理(pH 2.5)顯著增加土壤全氮含量和交換性酸含量,耗盡土壤交換性鹽基離子(特別是鈣離子),降低土壤pH值；中度酸沉降處理(pH3.5)下土壤pH值變化不顯著,表明土壤對酸沉降有一定的緩沖作用,只有當(dāng)添加的H+超過了閾值,土壤才發(fā)生進(jìn)一步酸化。短期硫酸型酸沉降處理(SAD)對土壤的酸化作用大于硝酸型酸沉降處理(NAD)。土壤酸化會隨著酸沉降的累積而逐漸加劇,土壤終將出現(xiàn)因鈣、鎂等養(yǎng)分缺失和有毒元素鋁的活化而引起的養(yǎng)分失衡狀況。3)木荷和濕地松幼苗生理生態(tài)和生長對酸度增加的響應(yīng)不一致。酸沉降對木荷幼苗葉片可見傷害隨酸度增加而增大。試驗第一年,高強(qiáng)度酸處理通過氣孔因素與葉綠素下降等非氣孔因素的共同作用,降低木荷葉片光合速率和相對生長速率；次年,酸沉降顯著提高木荷葉氮和葉綠素含量,并引起光合速率的小幅增加；但是連續(xù)兩個生長季的酸沉降處理未引起木荷生物量累積和分配的顯著變化。酸處理下濕地松針葉未出現(xiàn)明顯受害癥狀,酸度增加對濕地松光合速率的影響不顯著,但增加地上部分生物量分配,進(jìn)而促進(jìn)生物量累積。此外,濕地松的快速生長降低了土壤中氮的積累,可緩解酸沉降帶來的土壤酸化,因此更能適應(yīng)酸沉降環(huán)境,是南方酸沉降區(qū)優(yōu)質(zhì)的造林樹種。4)幼苗生理和生長對SAD和NAD的響應(yīng)并不一致。中等強(qiáng)度酸沉降處理下(pH 3.5), NAD對木荷葉片光合作用和生物量累積的抑制效應(yīng)大于SAD；高強(qiáng)度酸沉降下(pH 2.5), NAD的施肥作用在一定程度上緩解了酸沉降對木荷生理和生長的負(fù)效應(yīng),并對濕地松側(cè)枝生長和生物量累積產(chǎn)生了更為明顯的促進(jìn)作用。但是,長期過量的氮輸入造成的高氮可能會引起植物養(yǎng)分失衡,抵消由于高氮濃度誘導(dǎo)的凈光合速率增加的潛力。由以上結(jié)果可以發(fā)現(xiàn),由于酸沉降中H6等離子的毒害作用與營養(yǎng)物質(zhì)施肥效應(yīng)的不同,決定了植物對不同類型酸沉降響應(yīng)的差異。5)由于噴施方式的不同,酸沉降通過與植物葉片的直接接觸和通過酸化土壤的間接作用對植物生理生態(tài)和生長的影響存在差異,且并不同步。葉噴處理對木荷幼苗第一年飽和光合速率的抑制顯著大于土壤處理,并引起相對生長速率的下降,說明木荷在短期內(nèi)受到了直接的酸脅迫傷害；另外,短期土壤噴施(特別是NAD)可顯著提高幼苗葉氮和葉綠素含量,進(jìn)而促進(jìn)濕地松的生長。然而,酸沉降加劇了土壤酸化,且土壤交換性鋁離子和交換性氫離子含量是影響植物生長的主要限制因素。雖然酸沉降通過影響土壤化學(xué)性質(zhì)對林木生長的影響具有一定的時滯性,但其負(fù)效應(yīng)會隨著時間延長而逐漸凸顯。綜合來看,天童大氣降水酸化程度非常高,且酸沉降類型逐步由硫酸型向硫酸硝酸復(fù)合型轉(zhuǎn)變。林木生長對酸沉降的響應(yīng)因物種、酸沉降強(qiáng)度、類型和噴施方式的不同而存在很大差異：酸沉降對敏感植物的傷害隨酸度增大而加��；木荷在短期內(nèi)受到了直接的酸脅迫傷害,但在現(xiàn)有的降水酸度下,長期酸沉降導(dǎo)致的土壤酸化和養(yǎng)分缺失可能是林木生長的主要限制因素；酸沉降的酸化和施肥效應(yīng)的不同,決定了植物對不同類型酸沉降響應(yīng)的差異。未來持續(xù)酸沉降背景下,特別是酸沉降類型由SAD到NAD的轉(zhuǎn)變,亞熱帶常綠闊葉林對酸沉降的長期響應(yīng)值得進(jìn)一步深入研究。
[Abstract]:Acid deposition is one of the major environmental problems affecting human well-being at present and in the future, which has attracted wide attention of scholars both at home and abroad. South China is the third largest acid deposition area in the world after Europe and the United States, especially in Zhejiang Province, located in the Yangtze River Delta. Acidification may even lead to forest decline. Due to the different types of ecosystem, soil conditions, acid deposition intensity, type and duration, the effects of acid deposition on forest ecosystem are quite different. Therefore, it is urgent to understand the characteristics of Atmospheric Acid Deposition and its comprehensive effects on the physiological ecology and growth of common subtropical tree species. Based on the Tiantong Forest Ecosystem National Field Scientific Observation and Research Station in Zhejiang Province, the atmospheric wet acid deposition was monitored from March 2010 to February 2011 to study the dynamic changes of precipitation acidity and ion composition. The effects of different acidity (pH 3.5 and pH 2.5), acid deposition types (SO42-: NO3-8:1 and 0.7:1, respectively) and spraying methods (foliar spraying and soil irrigation) on seedling physiology, ecology and growth were studied. Combined with the analysis of soil chemical properties, the comprehensive response mechanism of plants to acid deposition and the key factors leading to the decline of forest ecosystem were discussed. The main results are as follows: 1) The acidification degree of Tiantong atmospheric precipitation is very high, the weighted average pH value of precipitation is 4.37, and the incidence of acid rain is 93.6%. The average concentrations of anion and cation weighted in the precipitation are 140.7 mu eq.L-1 and 158.9 mu e, respectively. Q L 1 showed obvious seasonal variation, and the pollution in winter and spring was significantly higher than that in summer and autumn. Atmospheric precipitation ion ion ion ion components contributed to a certain extent, but had no significant effect on acidity. 2) Heavy acid deposition (pH 2.5) significantly increased soil total nitrogen content and exchangeable acid content, depleted exchangeable base ions (especially calcium ions), and decreased soil pH; moderate acid deposition (pH 3.5) did not significantly change soil pH, indicating that soil pH. Soil has a buffer effect on acid deposition, and further acidification occurs only when the added H + exceeds the threshold value. Soil acidification by short-term sulfuric acid deposition (SAD) is greater than that by nitric acid deposition (NAD). Nutrient imbalance caused by the activation of toxic element Al. 3) Physiological ecology and growth of Schima superba and Pinus elliottii seedlings were inconsistent with the increase of acidity. In the following year, acid deposition significantly increased the contents of nitrogen and chlorophyll in Schima superba leaves and caused a slight increase in photosynthetic rate. However, acid deposition did not cause significant changes in biomass accumulation and distribution of Schima superba during the two successive growing seasons. In addition, the rapid growth of Pinus elliottii reduced the accumulation of nitrogen in the soil and alleviated the acidification of the soil caused by acid deposition, so it was more suitable for the acid deposition environment in southern China. 4. The response of seedling physiology and growth to SAD and NAD was not consistent. Under moderate acid deposition (pH 3.5), the inhibition effect of NAD on Photosynthesis and biomass accumulation of Schima superba leaves was greater than that of SAD; under high acid deposition (pH 2.5), NAD fertilization alleviated the physiological effect of acid deposition on Schima superba leaves to some extent. Negative effects on the growth and biomass accumulation of Pinus elliottii lateral branches were more prominent. However, long-term excessive nitrogen input may cause nutrient imbalance and offset the potential for increased net photosynthetic rate induced by high nitrogen concentration. The difference between the toxicity of ions and the effect of nutrient fertilization determines the difference of plant responses to different types of acid deposition. 5) Because of the different spraying methods, the effects of acid deposition on plant physiology, ecology and growth are different and not synchronous through direct contact with plant leaves and indirect action of acidified soil. The inhibition of saturated photosynthetic rate of Schima superba seedlings in the first year was significantly greater than that of soil treatment, and the relative growth rate was decreased, indicating that Schima superba was injured by direct acid stress in a short period of time. In addition, short-term soil spraying (especially NAD) could significantly increase leaf nitrogen and chlorophyll content of seedlings, thereby promoting the growth of Pinus elliottii. Soil acidification is aggravated by acid deposition, and exchangeable aluminum and hydrogen ions are the main limiting factors for plant growth. Although acid deposition has a time lag effect on tree growth by affecting soil chemical properties, its negative effects will gradually become prominent with time. The response of tree growth to acid deposition varies greatly with species, acid deposition intensity, types and spraying methods. The damage of acid deposition to sensitive plants increases with the increase of acidity; Schima superba is subjected to acid deposition in a short period of time. Soil acidification and nutrient deficiency caused by long-term acid deposition may be the main limiting factors for tree growth under the existing precipitation acidity, and the differences in response of plants to different types of acid deposition depend on the acidification and fertilization effects of acid deposition. The long-term response of subtropical evergreen broad-leaved forest to acid deposition deserves further study.
【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：S792.99;S791.246
，
本文編號：2194164
[Abstract]:Acid deposition is one of the major environmental problems affecting human well-being at present and in the future, which has attracted wide attention of scholars both at home and abroad. South China is the third largest acid deposition area in the world after Europe and the United States, especially in Zhejiang Province, located in the Yangtze River Delta. Acidification may even lead to forest decline. Due to the different types of ecosystem, soil conditions, acid deposition intensity, type and duration, the effects of acid deposition on forest ecosystem are quite different. Therefore, it is urgent to understand the characteristics of Atmospheric Acid Deposition and its comprehensive effects on the physiological ecology and growth of common subtropical tree species. Based on the Tiantong Forest Ecosystem National Field Scientific Observation and Research Station in Zhejiang Province, the atmospheric wet acid deposition was monitored from March 2010 to February 2011 to study the dynamic changes of precipitation acidity and ion composition. The effects of different acidity (pH 3.5 and pH 2.5), acid deposition types (SO42-: NO3-8:1 and 0.7:1, respectively) and spraying methods (foliar spraying and soil irrigation) on seedling physiology, ecology and growth were studied. Combined with the analysis of soil chemical properties, the comprehensive response mechanism of plants to acid deposition and the key factors leading to the decline of forest ecosystem were discussed. The main results are as follows: 1) The acidification degree of Tiantong atmospheric precipitation is very high, the weighted average pH value of precipitation is 4.37, and the incidence of acid rain is 93.6%. The average concentrations of anion and cation weighted in the precipitation are 140.7 mu eq.L-1 and 158.9 mu e, respectively. Q L 1 showed obvious seasonal variation, and the pollution in winter and spring was significantly higher than that in summer and autumn. Atmospheric precipitation ion ion ion ion components contributed to a certain extent, but had no significant effect on acidity. 2) Heavy acid deposition (pH 2.5) significantly increased soil total nitrogen content and exchangeable acid content, depleted exchangeable base ions (especially calcium ions), and decreased soil pH; moderate acid deposition (pH 3.5) did not significantly change soil pH, indicating that soil pH. Soil has a buffer effect on acid deposition, and further acidification occurs only when the added H + exceeds the threshold value. Soil acidification by short-term sulfuric acid deposition (SAD) is greater than that by nitric acid deposition (NAD). Nutrient imbalance caused by the activation of toxic element Al. 3) Physiological ecology and growth of Schima superba and Pinus elliottii seedlings were inconsistent with the increase of acidity. In the following year, acid deposition significantly increased the contents of nitrogen and chlorophyll in Schima superba leaves and caused a slight increase in photosynthetic rate. However, acid deposition did not cause significant changes in biomass accumulation and distribution of Schima superba during the two successive growing seasons. In addition, the rapid growth of Pinus elliottii reduced the accumulation of nitrogen in the soil and alleviated the acidification of the soil caused by acid deposition, so it was more suitable for the acid deposition environment in southern China. 4. The response of seedling physiology and growth to SAD and NAD was not consistent. Under moderate acid deposition (pH 3.5), the inhibition effect of NAD on Photosynthesis and biomass accumulation of Schima superba leaves was greater than that of SAD; under high acid deposition (pH 2.5), NAD fertilization alleviated the physiological effect of acid deposition on Schima superba leaves to some extent. Negative effects on the growth and biomass accumulation of Pinus elliottii lateral branches were more prominent. However, long-term excessive nitrogen input may cause nutrient imbalance and offset the potential for increased net photosynthetic rate induced by high nitrogen concentration. The difference between the toxicity of ions and the effect of nutrient fertilization determines the difference of plant responses to different types of acid deposition. 5) Because of the different spraying methods, the effects of acid deposition on plant physiology, ecology and growth are different and not synchronous through direct contact with plant leaves and indirect action of acidified soil. The inhibition of saturated photosynthetic rate of Schima superba seedlings in the first year was significantly greater than that of soil treatment, and the relative growth rate was decreased, indicating that Schima superba was injured by direct acid stress in a short period of time. In addition, short-term soil spraying (especially NAD) could significantly increase leaf nitrogen and chlorophyll content of seedlings, thereby promoting the growth of Pinus elliottii. Soil acidification is aggravated by acid deposition, and exchangeable aluminum and hydrogen ions are the main limiting factors for plant growth. Although acid deposition has a time lag effect on tree growth by affecting soil chemical properties, its negative effects will gradually become prominent with time. The response of tree growth to acid deposition varies greatly with species, acid deposition intensity, types and spraying methods. The damage of acid deposition to sensitive plants increases with the increase of acidity; Schima superba is subjected to acid deposition in a short period of time. Soil acidification and nutrient deficiency caused by long-term acid deposition may be the main limiting factors for tree growth under the existing precipitation acidity, and the differences in response of plants to different types of acid deposition depend on the acidification and fertilization effects of acid deposition. The long-term response of subtropical evergreen broad-leaved forest to acid deposition deserves further study.
【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：S792.99;S791.246
，
本文編號：2194164
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