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1.
利用Photosynq MultiseQ多功能植物测量仪测定塔克拉玛干沙漠腹地3种主要防护林植物头状沙拐枣、多枝柽柳和梭梭的叶绿素荧光参数日变化,探讨其与环境因子的关系,以揭示3种植物对极端环境的适应策略,为沙漠公路防护林的管护提供理论依据。结果表明:1)3种土壤都呈碱性;0~30 cm土层中的电导率(EC)远高于30 cm以下的土层。1 m内梭梭土层中的含水量高于多枝柽柳高于头状沙拐枣。2)3种植物的光合有效辐射(PAR)、叶片温度和线性电子传递(LEF)及植物周围的大气温度日变化均先升后降,且都在14:00达到最高;而大气湿度、实际光化学效率Y(II)日变化均呈‘V’型。3)PAR基本上与3种植物的LEF、非光化学淬灭系数(NPQ)、调节性能量耗散量子产量Y(NPQ)、非调节性能量耗散量子产量Y(NO)呈显著正相关,与实际光化学效率Y(II)呈显著负相关;3种植物的Y(II)与Y(NPQ)、Y(NO) 均呈极显著负相关。3种植物的LEF、Y(II)、Y(NPQ)的日均值差异不显著,但梭梭与多枝柽柳的NPQ和Y(NO)日均值差异显著。4)在3种植物的叶绿素荧光参数中,梭梭和头状沙拐枣的LEF、NPQ和Y(II)要高于多枝柽柳;而多枝柽柳的Y(NO)要显著高于头状沙拐枣和梭梭。因此,高温和高光均对3种植物造成了不同程度的影响,通过主成分分析表明,3种植物的抗逆性强弱顺序分别为梭梭>头状沙拐枣>多枝柽柳。  相似文献   
2.
冻融对东北黑土硒酸盐吸附解吸的影响   总被引:2,自引:0,他引:2  
行文静  牛浩  李娇  吴福勇 《土壤通报》2021,52(2):338-345
为探究冻融过程对东北黑土硒酸盐(Se(VI))吸附、解吸的影响机理,通过室内不同初始含水率及冻融次数模拟冻融循环,随后利用冻融后土壤进行Se(VI)的吸附和解吸试验,分别采用Langumuir和Freundlich方程对Se(VI)吸附过程进行拟合。结果表明:冻融显著(P < 0.05)改变了东北黑土pH值、有机质、球囊霉素相关土壤蛋白及各粒级团聚体含量,冻融后土壤Se(VI)吸附量显著高于未冻融土壤。通过拟合发现东北黑土对Se(VI)的吸附更符合Langmuir模型(R2 > 0.967),高初始含水率及冻融循环次数均增加了冻融后黑土对Se(VI)的最大吸附量及缓冲容量,同时提高了Se(VI)的解吸率。70%含水率及多次冻融循环提高了黑土对Se(VI)的吸附潜能,促进Se(VI)的解吸,使得冻融后土壤硒的生物有效性增加,有利于作物根系对硒的吸收。  相似文献   
3.
采集我国15个省份的耕作土壤进行盆栽试验,通过外源添加不同浓度梯度的Pb并种植小白菜,比较梯度薄膜扩散技术(Diffusive gradients in thin-films,DGT)与传统化学方法(土壤溶液法、EDTA法、HAc法、CaCl_2法和全量法)评价土壤中Pb生物有效性。简单回归分析表明,各评价方法测定的土壤Pb含量与小白菜Pb含量都呈显著相关关系,但DGT技术相关性(R~2=0.97)最高。通过逐步多元线性回归分析,融合土壤pH值、有机碳(OC)含量、阳离子交换量(CEC)、粘粒含量等土壤基本理化性质,建立多元回归模型,结果表明:各传统评价方法融合了pH值、OC含量等土壤性质,R~2较对应的简单回归分析有所提高,都能用于评价土壤Pb的生物有效性,但通过DGT技术所构建的模型方程(R~2=0.97,p0.01)几乎不受土壤性质的影响,且较传统化学方法相关性更高,因此,DGT技术是一种可以用于评价土壤中Pb生物性的较优方法。  相似文献   
4.
小麦与秋豆秸秆配施对土壤有机碳固持的影响   总被引:1,自引:0,他引:1  
为揭示麦秸与豆科秸秆配合还田对黑垆土有机碳固持的影响,尝试引入了自然δ13C技术并结合双指数模型方法,选取常年种植玉米的C4土壤,设不添加秸秆(CK)、添加小麦秸秆(W)、添加秋豆秸秆(L)、小麦秋豆秸秆组合添加(W+L)4个处理,进行了80d的恒温控湿室内培养试验。结果表明:培养结束后,秸秆添加处理(W+L、L、W)显著提高了CO_2累积释放量和有机碳含量,分别比CK高5.63、2.90、2.60倍和22.3%、10.7%和12.5%;W+L处理显著提高了土壤微生物量碳及微生物熵,分别比CK高39.5%和15.6%;同时W+L、L、W处理也提高了土壤惰性碳库及其占总有机碳的比例,分别比CK高2.82、0.756、1.98倍和2.27、0.569、1.64倍。较W处理,W+L处理的CO_2累积释放量、惰性碳库及其在土壤碳库所占比例和微生物量碳及微生物熵均明显增加,增加幅度分别为84.4%、28.1%、23.9%、25.3%和14.5%;同时,W+L处理明显提高了碳库中来自秸秆的新碳含量(Cstraw)及其所占比例(f),分别比W高86.5%和79.8%,且两种秸秆组合的土壤累积矿化量、有机碳含量和微生物量碳氮都表现出"加和效应"。综上,相比于禾本科作物秸秆单独还田,配施豆科绿肥秸秆会大幅提高土壤有机碳矿化量,同时仍能形成更多来自秸秆的新碳和增加土壤碳库稳定性,有利于土壤有机碳固持,且两种秸秆组合的"加和效应"在土壤固碳过程中发挥重要作用。  相似文献   
5.
Understanding the mechanism of soil organic carbon(SOC) sequestration is of paramount importance in sustaining crop productivity and mitigating climate change. Long-term trials were employed to investigate the responses of total SOC and its pools, i.e., mineral-associated OC(MOC), particulate OC(POC, containing Light-POC and Heavy-POC), to fertilization regimes at Yangling(25-year), Tianshui(35-year) and Pingliang(37-year) under a rain-fed cropping system in the Loess Plateau. The fertilization regimes in each trial included three treatments, i.e., control(no nutrient input, CK), chemical fertilizers(CF), and organic manure plus chemical fertilizers(MCF). Relative to the CK, long-term fertilization appreciably increased SOC storage by 134, 89 and 129 kg ha~(–1) yr~(–1) under CF, and 418, 153 and 384 kg ha~(–1) yr~(–1) under MCF in plough layer soils(0–20 cm), respectively, at the Yangling, Tianshui and Pingliang sites. The MOC pools accounted for 72, 67 and 64% of the total SOC at the above three sites with sequestration rates of 76, 57 and 83 kg ha~(–1) yr~(–1) under CF and 238, 118 and 156 kg ha~(–1) yr~(–1) under MCF, respectively. Moreover, the MOC pool displayed a saturation behavior under MCF conditions. The POC accordingly constituted 27, 33 and 36% of SOC, of which Light-POC accounted for 11, 17 and 22% and Heavy-POC for 17, 16 and 15% of SOC, respectively. The sequestration rates of POC were 58, 32 and 46 kg ha~(–1) yr~(–1) under CF, and 181, 90 and 228 kg ha~(–1) yr~(–1) under MCF at the three respective sites, in which Light-POC explained 59, 81 and 72% of POC under CF, and 60, 40 and 69% of POC under MCF, with Heavy-POC accounting for the balance. Compared with CK, the application of CF alone did not affect the proportions of MOC or total POC to SOC, whereas MCF application markedly reduced the proportion of MOC and increased the POC ratio, mainly in the Light-POC pool. The distribution of SOC among different pools was closely related to the distribution and stability of aggregates. The present study confirmed that organic manure amendment not only sequestered more SOC but also significantly altered the composition of SOC, thus improving SOC quality, which is possibly related to the SOC saturation level.  相似文献   
6.
研究秦岭山区2种林分土壤性质的季节性变化对土壤细菌群落多样性和结构特征影响,为该区生态恢复及物质循环提供理论依据。以云杉林和红桦林土壤为对象,采用Illumina Miseq高通量测序技术初步探讨了这2种林分不同季节土壤细菌多样性(Chao1指数和Shannon指数)和群落组成,并采用相关分析和冗余分析(RDA)等方法,探讨了土壤性质,包括pH、土壤温度、土壤含水量(SWC)、土壤有机碳(SOC)、可溶性有机碳(EOC)、微生物生物量碳(MBC)和易氧化有机碳(DOC)对土壤细菌多样性和群落的影响。结果表明:1)2种林分土壤细菌Chao1指数和Shannon指数具有明显的季节性变化特征,夏季最高,冬季最低,春季和秋季居中。2)2种林分土壤中酸杆菌门、拟杆菌门和变形菌门为优势菌门,酸杆菌门相对丰度在秋季最大,冬季最低,而拟杆菌门相对丰度则相反,在冬季达到最大值,秋季最低。3)相关分析表明,细菌多样性与温度负相关,与土壤pH、SWC、SOC、EOC、DOC和MBC含量正相关。4)RDA分析结果表明,SWC是影响真菌群落组成季节性变化的主要因素,其次是EOC和SOC含量。这些研究结果表明,秦岭林区土壤细菌群落多样性及群落组成的季节性变化是土壤养分及土壤环境因素(温度和含水量)共同作用的结果。  相似文献   
7.
石灰和有机质对不同性质镉污染土壤中镉有效性的影响   总被引:22,自引:16,他引:6  
通过土培试验研究了添加不同改良剂(鸡粪、泥炭和石灰)对我国不同性质土壤(云南赤红壤、江西红壤、吉林黑土和内蒙栗钙土)镉污染的改良差异。结果表明,不同改良剂0~60 d内对四种镉污染土壤的改良效果均较为显著。鸡粪对云南赤红壤、江西红壤、吉林黑土和内蒙栗钙土镉污染的固定率分别为37.0%、52.7%、29.3%和49.6%,显示鸡粪对这四种不同性质镉污染土壤的改良效果是江西红壤≈内蒙栗钙土云南赤红壤吉林黑土;泥炭对云南赤红壤、江西红壤、吉林黑土和内蒙栗钙土镉污染的固定率分别为33.1%、51.7%、30.5%和51.2%,显示泥炭对这四种不同性质镉污染土壤的改良效果是江西红壤≈内蒙栗钙土吉林黑土≈云南赤红壤;石灰对云南赤红壤、江西红壤、吉林黑土和内蒙栗钙土镉污染的固定率分别为60.7%、55.5%、40.7%、41.7%,显示石灰对这四种不同性质镉污染土壤的改良效果是云南赤红壤江西红壤吉林黑土≈内蒙栗钙土。综上可知,在对镉污染的酸性土壤改良上,石灰好于有机质,而对镉污染的中性和碱性土壤改良上,有机质则好于石灰。  相似文献   
8.
Potassium(K) and magnesium(Mg) levels and their balances are two factors affecting the growth of plant. However, the responses of different crop cultivars to K/Mg ratios are less clear. This study was aimed at assessing the different responses of tomato(Solanum Lycopersicum L.) cultivars to the different K/Mg supply ratios. Three tomato cultivars(Zhongza 9(ZZ), Gailiangmaofen(MF), and Jinpengchaoguan(JP)) were grown in pots with three different K~+/Mg~(2+) ratios(4:0, 4:1 and 8:1, represented by K/Mg_(4:0), K/Mg_(4:1), and K/Mg_(8:1), respectively). Compared with K/Mg_(4:1) treatment, the leaf chlorophyll content, net photosynthetic rate, and total biomass of tomato seedlings under K/Mg_(4:0) treatments were decreased by 69.7, 89.1, and 53.1%, respectively. The Mg deficiency symptoms were observed when the Mg content in shoot became lower than 4 mg g~(–1) DW. Compared with K/Mg_(4:1) treatment, total biomass of tomato seedlings of K/Mg_(8:1) treatment was decreased by 21.6%; the shoot and root Mg contents were decreased by 10.4 and 21.8%, respectively; and Mg uptake of tomato was reduced by 34.1%. There were significant differences in biomass and Mg uptake for the three cultivars between the different K~+/Mg~(2+) treatments. The Mg uptake of the three different cultivars ranked as ZZJPMF under Mg deficiency and high K condition. In conclusion, the growth and Mg uptake and allocation of tomato were influenced significantly by imbalance K and Mg supply. JP and ZZ were the cultivars with the highest efficiency in Mg uptake.  相似文献   
9.
Glutamine synthetase (GS) plays a central role in plant nitrogen (N) metabolism, which improves crops grain protein content. A pot experiment in field condition was carried out to evaluate GS expression and activity, and grain protein content in high (Wanmai16) and low grain protein (Loumai24) wheat cultivars under two N levels (0.05 and 0.15 g N kg−1 soil). High nitrogen (HN) resulted in significant increases in GS1 and GS2 expression at 10 days after anthesis (DAA), and higher GS activity during the entire grain filling stage. HN also significantly increased yield, grain protein content and protein fraction (except for glutenin of Luomai24) in two wheat cultivars, which indicated that it increased grain yield and protein content by improving nitrogen metabolism. Wanmai16 showed higher grain protein content, gliadin and glutenin content, and had higher expression level of GS2 both in flag leaves and grains at early grain filling stage. However, Luomai24 had greater yield and higher expression level of GS1. The difference expression of GS2 and GS1 genes indicates they had various contributions to the accumulation of protein and starch in wheat grains, respectively. The results suggest that GS2 would be serving as a potential breeding target for improving wheat quality.  相似文献   
10.
添加矿物质对猪粪好氧堆肥中有机物降解的影响   总被引:2,自引:0,他引:2  
为了探讨添加矿物材料对猪粪堆肥过程中有机物动态变化的影响,通过好氧堆肥的方式向猪粪和玉米秸秆粉混合物料中添加干质量分数为2.5%的粉煤灰、膨润土和风化煤等矿物质,用化学分析和红外光谱技术相结合的方法,对90 d好氧高温堆肥过程中有机质的动态变化特征进行了研究。结果表明:添加粉煤灰、风化煤或膨润土对猪粪堆肥的堆体温度变化均无明显影响,堆体温度能迅速升至近70℃,并维持在55℃以上超过7 d,达到高温堆肥的温度要求;随着堆肥时间的延长,各处理中总有机碳(TOC)和水溶性有机碳(WSC)含量均呈现出逐渐降低最后趋于相对稳定的趋势,但添加粉煤灰、风化煤和膨润土处理,能促进有机质的降解,促进能力依次为粉煤灰、膨润土、风化煤;添加粉煤灰、风化煤和膨润土等矿物质有利于猪粪堆肥的腐殖化过程进行,堆肥过程的雪里蕻种子萌发指数(GI)与WSC显著负相关、GI与胡敏酸的百分比(PHA)和腐殖酸聚合度(DP)显著正相关;红外光谱数据显示,在好氧堆肥过程中,含有—OH、—CH3和—CH2基团的化合物相对减少,而含有—CO、C—O—C、—COO基团和含芳香环类物质的含量逐渐增加,堆肥有机质降解可持续至60 d以后;添加粉煤灰、风化煤和膨润土会影响堆肥初期GI增加,但经过90 d好氧堆肥后,雪里蕻种子的GI均能大于0.5,所有堆肥处理均基本达到腐熟水平。  相似文献   
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