【作者】 王利民；

【导师】 陈金林；

【作者基本信息】 南京林业大学 ， 生态学， 2010， 博士

【摘要】 滨海盐土含盐多、pH值高、结构差、肥力低,对植物生长和生态环境均有很大影响,因此,改良利用盐土具有重要意义。通过田间试验研究黄麻(Corchorus capsularis L.)连作、稻-菜轮作、稻-麦轮作以及黄麻秸秆与鸡粪配施等改良利用技术对盐土理化性状及生物性质的影响;通过盆栽试验研究滨梅(Prunus maritima)、鸡桑(Morus australis)等植物的耐盐机制和滨梅、美国白蜡(Fraxinus americana)根际微域矿质元素相对质量分数及其分布。研究结果表明:⑴黄麻连作、稻-菜轮作和稻-麦轮作2 a后,0～20 cm土层的土壤密度比滨海盐土荒地分别降低了16.11%、13.42%、9.40%,黄麻连作、稻-菜轮作20～40 cm土层的土壤密度比滨海盐土荒地降低了5.30%、5.962%,而稻-麦轮作无明显差异。黄麻连作、稻-菜轮作0～20 cm土层的土壤有机质含量比滨海盐土荒地分别增加了26.66%、47.93%,20～40 cm土层增加了21.92%、9.46%,40～60 cm土层增加了15.46%、9.36%,而稻-麦轮作无明显影响。与滨海盐土荒地相比,各利用方式的土壤阳离子交换量(CEC)、全N、水解性N、速效K含量均增加,而全盐量和pH减小。黄麻连作、稻-菜轮作和稻-麦轮作的土壤蛋白酶活性比滨海盐土荒地分别增加了2.24、0.61、2.00倍,脲酶、过氧化氢酶、磷酸酶也增加。黄麻连作、稻-菜轮作和稻-麦轮作的土壤微生物总数分别比滨海盐土荒地增加了45.98、24.66、2.27倍,其中,细菌、放线菌、真菌均有不同程度增加。主成分分析可知,稻-菜轮作改良效应较好,黄麻连作次之,稻-麦轮作较弱。⑵黄麻秸秆(A1、A2、A3)和鸡粪(B1、B2、B3)2个因素分设1 200、2 400、3 600 kg·hm-2 3个施用量水平。A3B1、A3B2、A3B3处理0～20 cm土层的土壤密度比CK分别降低了4.79%、6.85%、7.53%,而其它处理无明显差异。同时,土壤持水量、孔隙度随秸秆和鸡粪施用量增加而升高。A1B2～A3B3的8个处理0～20 cm土层的土壤有机质含量比CK分别增加了7.64%、8.82%、8.45%、16.73%、13.64%、25.36%、36.64%、54.64%,而A1B1无显著增加。另外,土壤N、P、K和CEC随秸秆和鸡粪施用量增加而上升,而pH、全盐量下降。A1B1～A3B3的9个处理土壤蛋白酶活性较CK分别增加了35.94%、191.48%、54.83%、67.49%、264.50%、89.98%、196.57%、274.34%、211.34%,同样,磷酸酶、蔗糖酶、过氧化氢酶、脲酶活性以及细菌、真菌数量随秸秆和鸡粪施用量增加而上升。通过主成分分析和聚类分析,A3B2、A3B3处理的盐土综合性状改良效果较好;A2B1、A2B2、A3B1、A2B3其次;CK、A1B1、A1B2、A1B3较弱。⑶低质量浓度(3 g·L-1)NaCl处理下滨梅根细胞未受明显伤害,但高质量浓度(9 g·L-1)NaCl胁迫导致根细胞内降解物质增多,细胞器降解,细胞核染色质降低,质膜局部内陷,但未出现质壁分离。同时,盐分处理下滨梅根含水率、根内Ca2+、叶中Mg2+、叶中Cl-、根内Na+和叶中Na+等含量增加。另一植物鸡桑在盐分处理下根含水率、脯氨酸、超氧化物岐化酶(SOD)、过氧化物酶(POD)、根内Ca2+、根内Mg2+、叶中Mg2+、根内Cl-、叶中Cl-、根内Na+和叶中Na+等含量增加。⑷滨梅根系Na、Mg的累积量随盐浓度升高而增加,9 g·L-1盐胁迫下Ca、Mg、K均向根中柱聚集。滨梅根际Cl的质量分数较低,同时,盐处理使Cl在0～100μm从对照(0 g·L-1)的累积状态转为亏缺,且盐处理滨梅根系Cl的累积量均比对照高。此外,滨梅根际Fe的质量分数较高。另一植物白蜡在对照条件下根系Cl、Ca、Na的累积量较少,低质量浓度(3 g·L-1)盐处理下白蜡根系Na、Cl、Ca、Mg的聚集量较多。高质量浓度(9 g·L-1)盐胁迫下白蜡根系Na、Ca、Mg、Cl的累积量降低,但K、Fe、Zn却升高,同样根际Na的质量分数也较高。与对照相比,盐处理使白蜡根中柱K、Ca、Mg的聚集量增加。白蜡根际0～100μm,对照Fe出现累积,而其它处理存在亏缺;9 g·L-1盐处理和对照根内Fe的质量分数均远高于3 g·L-1处理。综上,①各利用方式均增加土壤有机质,提高养分,改善通透性、持水力,增强生物活性,促进养分循环,且上层土壤改良效应较下层好。其中,这些利用方式的盐土改良效应大小为稻-菜轮作>黄麻连作>稻-麦轮作>滨海盐土荒地。②秸秆与鸡粪配施增加土壤有机质,降低土壤密度,增强土壤通透性和保蓄性,加速土体脱盐,降低pH,增加土壤N、P、K含量,提高蛋白酶、尿酶、蔗糖酶、过氧化氢酶和磷酸酶活性,增加微生物数量。不同用量的秸秆和鸡粪配施改良滨海盐土的效果分为3类,即CK、A1B1、A1B2、A1B3为第一类,改良效果较弱;A2B1、A2B2、A3B1、A2B3为第二类,改良效果中等;A3B2、A3B3为第三类,改良效果较强。③盐胁迫下,滨梅主要通过以下途径适应盐渍生境,增加根含水率,提高根内Ca2+、叶中Mg2+含量,但同时另一组指标如叶中Cl-、根内Na+和叶中Na+等含量增至滨梅耐受限度以外,则削弱滨梅的耐盐性,进而诱发盐害。鸡桑盐害的主要原因为根内Na+、叶中Na+、根内Cl-和叶中Cl-等含量过度增加,但同时其根含水率、脯氨酸、SOD、POD、根内Ca2+、根内Mg2+、叶中Mg2+等指标值增加有助于缓解盐害。④盐胁迫条件下,滨梅根系吸收累积过量的Na是导致盐害的重要原因,而滨梅根系Cl、Fe的吸收量与盐害关系不密切。另一植物白蜡根系吸收累积过量的Na、Cl,从而诱发盐害,至于根内过高的Fe是否也为盐胁迫的诱因有待研究。更多还原

【Abstract】 Due to its inferior characteristics such as high pH value, high salinity, poor structure, and low fertility, coastal solonchak has adverse effect on both plant growth and eco-environment. Therefore, it is important to improve and utilize the soil. This author researched effects of continuous cropping by jute, rotation by paddy and rape, rotation by paddy and wheat on the physico-chemical properties and biological properties for the coastal solonchak, and researched ameliorative effects of different level of jute straw and chicken manure on the soil by way of field experiment. Moreover, pot culture experiments were conducted to document the salt-tolerant mechanisms of beach plum (Prunus maritima) and Japanese mulberry (Morus australis) and to assess the contents and distributions of salinity on mineral elements in rhizosphere microzone of beach plum and white ash (Fraxinus americana) under four salinity levels (0, 3, 6, and 9 g·L-1 NaCl in the irrigation water). The results were shown as follows:⑴The coastal solonchak was ameliorated by each land use. Compared with the control, for three plots by continuous cropping with jute, rotation with paddy and rape, rotation with paddy and wheat for two-year, their soil density at the 0～20 cm soil layer was respectively decreased by 16.11%, 13.42%, and 9.40%, decreased by 5.30% and 5.96% at the 20～40 cm, whereas no significant changes occurred between the plot by rotation with paddy and wheat and the control. Compared with the control, for the plots by continuous cropping with jute, rotation with paddy and rape, their organic content was respectively increased by 26.66 % and 47.93% at the 0～20 cm soil layer, increased by 21.92% and 9.46% at the 20～40 cm, increased by 15.46% and 9.36% at the 40～60 cm, but the organic content was not significantly increased by rotation with paddy and wheat. In addition, soil cation exchange capacity (CEC), total N, hydrolysable N, available K were all promoted, whereas soil salt content and pH value were reduced by way of those land use. For the plots by continuous cropping with jute, rotation with paddy and rape, rotation with paddy and wheat, their soil protease activity at the 0～20 cm soil layer was respectively increased by 2.24, 0.61, and 2.00 times as against the control, microbes by 45.98, 24.66, and 2.27 times. Moreover, the number of bacteria, of actinomycetes, of fungi and activity of urase, of hydrogen peroxidase, of phosphatase were also increased. By using principal component analysis, the plot by rotation with paddy and rape ranked the highest, whereas the lowest by rotation with paddy and wheat in terms of the ameliorative effect.⑵Jute straw (A1, A2, A3) and chicken manure (B1, B2, B3) have 3 application levels (1 200, 2 400, and 3 600 kg·hm-2) respectively. Compared with CK, for A3B1, A3B2, and A3B3, their soil density at the 0～20 cm soil layer was decreased by 4.79%, 6.85%, and 7.53% respectively, whereas the differences in soil density among other treatments were not significant. Compared to CK, the organic content from A1B2 to A3B3 was increased by 7.64%, 8.82%, 8.45%, 16.73%, 13.64%, 25.36%, 36.64%, 54.64% except A1B1. Meanwhile, soil N, P, K, and CEC were also rised with organic fertilizer addition, and pH value, salt content were declined. The soil protease activity from A1B1 to A3B3 was increased by 35.94%, 191.48%, 54.83%, 67.49%, 264.50%, 89.98%, 196.57%, 274.34%, 211.34% compared with CK, so are phosphatase, invertase, hydrogen peroxidase, urease, fungus, and bacterium. According to principal component analysis and cluster analysis, the ameliorative effect of A3B2, A3B3 is good, that of A2B1, A2B2, A3B1, and A2B3 takes second place, and that of CK, A1B1, A1B2, A1B3 is weak.⑶Beach plum came to no harm at low salinity (3 g·L-1), whereas at high salinity (9 g·L-1) it was observed that the addition of the degradable substance in the cell, organelle degradation, the nucleus chromatin reduction, and part invagination of plama membranes, but the plasmolysis did not occur. Meanwhile, NaCl treatments stimulated an increase in these parameters, i.e., water content in the root of beach plum, Ca2+ content in the root, Mg2+ content in the leaf, Cl- content in the leaf and Na+ content in the leaf or the root. In addition, salt treatments led to an increase in water content in the root of Japanese mulberry, proline content, activity of superoxide dismutase (SOD) and peroxidase (POD), the content of Ca2+, Mg2+ in the root, the content of Mg2+ in the leaf, Cl- content in the root or the leaf, and Na+ content in the leaf or the root.⑷K, Mg, and Ca were aggregated in the stele of the root of beach plum under the treatment of 9 g·L-1 NaCl. Meanwhile, contents of Na, Mg in the root were increased with the addition of NaCl concentration. Cl content was relatively low in the rhizosphere of beach plum. NaCl treatments made Cl transform its accumulation into a deficit at 1～100μm in the rhizosphere of beach plum, and the content of Cl in the root was higher under the NaCl treatments compared to the control. The content of Fe was high in rhizosphere of beach plum. Contents of Cl, Ca, and Na in the root of white ash were low under the control. Contents of Na, Cl, Ca, and Mg in the root of white ash were higher at low salinity (3 g·L-1) compared to the control. At high salinity (9 g·L-1), contents of Na, Ca, Mg, and Cl in the root of white ash were declined, and increased for K, Fe, Zn. Meanwhile, the content of Na was relatively high in the rhizosphere, K, Ca, and Mg were accumulated in the stele of white ash under the NaCl treatments. The accumulation for Fe occurred at 1~100μm in the rhizosphere of white ash under the control, but the deficit for Fe under the NaCl treatments. Moreover, the content of Fe in the root was higher compared with the treatment of 3 g·L-1 NaCl.Those results indicated that:①Each land use can increase the organic content, improve soil perviousness and water retention ability, raise soil nutrients, enhance biological activity, promote nutrient cycle, and the ameliorative effect at the 0～20 cm soil layer was better than that in 20～40 cm or 40～60 cm. Those land use was put in order with ameliorative effect: rotation with paddy and rape>continuous cropping with jute>rotation with paddy and wheat>barren coastal solonchak.②The application of jute straw and chicken manure increased the organic content, reduced soil density, enhanced soil perviousness, accelerated desalting, reduced pH value, raised soil N, P, K content. Moreover, the activity of soil urease, invertase, hydrogen peroxidase, phosphatase was increased with the addition of jute straw and chicken manure, and the change of the microbial number is similar to that of those enzymes activity. The classification of the coastal solonchak according to ameliorative effect of different levels of jute straw and chicken manure was obtained, namely CK, A1B1, A1B2, A1B3 belonging to the first kind, their weak amelioration; A2B1, A2B2, A3B1, A2B3 belonging to the second kind, their medium amelioration; A3B2, A3B3 belonging to the third kind, their strong amelioration.③Beach plum has evolved its mechanisms to adapt to salt stress by the following way: an increase in water content in the root, an accumulation in the content of Ca2+ in the root, of Mg2+ in the leaf of beach plum, but the salt-tolerance of beach plum was weakened by a simultaneous increase in the content of Cl- in the leaf, the content of Na+ in the root or the leaf. It was an excess of the content of Na+ in the root or the leaf of Japanese mulberry, the content of Cl- in the root or the leaf that caused the salt injury. However, Japanese mulberry’s positive response to salinity depends on the following way: an increase in water content in the root, an accumulation of proline, an ascent in activity of SOD and POD, an increase in the content of Ca2+, Mg2+ in the root, in the content of Mg2+ in the leaf.④The root absorption of Cl, Fe didn’t correlate closely with salt injury of beach plum, whereas over-accumulation of Na might be main mechanism of generating salt injury. Over-accumulation of Na, Cl in the root resulted in salt injury of white ash, but it is not known for Fe.更多还原