菜园土壤不同施肥模式下小青菜生长和品质及其生态化学计量学特征

利用盆栽试验研究了不同施肥处理对小青菜生长和品质的影响,并在此基础上利用生态化学计量学方法研究了小青菜生长和品质与其生态化学计量学特征之间的相关关系。结果表明在盆栽的条件下施氮量为180kg/hm2是小青菜生长较为合适的水平,能达到节氮保产的效果。在氮水平为180kg/hm2下,有机无机肥配施模式1(含有氨基酸肥料)提高了小青菜地上部的生长、碳浓度、光合速率、可溶性总糖、蔗糖、游离氨基酸含量和根系鲜重,且这些指标与其地上部C/N(碳氮比)和C/P(碳磷比)之间存在显著正相关关系,而与施肥模式中C/N和C/P之间存在正相关趋势,但相关关系不显著。此外,有机无机肥配施模式1降低了小青菜的地上部硝酸盐含量,且该指标与其地上部和施肥模式中N/P(氮磷比)、C/N、C/P和P/K(磷钾比)之间均不存在相关关系。因此,有机无机肥配施模式1促进了小青菜地上部和根系生长,提高了光合速率,改善了小青菜地上部的品质,是一种科学的施肥措施。     

Soil texture affects soil microbial and structural recovery during grassland restoration

Many biotic and abiotic factors influence recovery of soil communities following prolonged disturbance. We investigated the role of soil texture in the recovery of soil microbial community structure and changes in microbial stress, as indexed by phospholipid fatty acid (PLFA) profiles, using two chronosequences of grasslands restored from 0 to 19 years on silty clay loam and loamy fine sand soils in Nebraska, USA. All restorations were formerly cultivated fields seeded to native warm-season grasses through the USDA’s Conservation Reserve Program. Increases in many PLFA concentrations occurred across the silty clay loam chronosequence including total PLFA biomass, richness, fungi, arbuscular mycorrhizal fungi, Gram-positive bacteria, Gram-negative bacteria, and actinomycetes. Ratios of saturated:monounsaturated and iso:anteiso PLFAs decreased across the silty clay loam chronosequence indicating reduction in nutrient stress of the microbial community as grassland established. Multivariate analysis of entire PLFA profiles across the silty clay loam chronosequence showed recovery of microbial community structure on the trajectory toward native prairie. Conversely, no microbial groups exhibited a directional change across the loamy fine sand chronosequence. Changes in soil structure were also only observed across the silty clay loam chronosequence. Aggregate mean weighted diameter (MWD) exhibited an exponential rise to maximum resulting from an exponential rise to maximum in the proportion of large macroaggregates (>2000 μm) and exponential decay in microaggregates (<250 μm and >53 μm) and the silt and clay fraction (<53 μm). Across both chronosequences, MWD was highly correlated with total PLFA biomass and the biomass of many microbial groups. Strong correlations between many PLFA groups and the MWD of aggregates underscore the interdependence between the recovery of soil microbial communities and soil structure that may explain more variation than time for some soils (i.e., loamy fine sand). This study demonstrates that soil microbial responses to grassland restoration are modulated by soil texture with implications for estimating the true capacity of restoration efforts to rehabilitate ecosystem functions.     

土施纳米氧化锌对蚯蚓生理和黄瓜幼苗生长的影响

纳米氧化锌(ZnO NPs)由于其独特的理化性质,被广泛应用于各行各业,在带来巨大利益的同时也存在着潜在风险,如细胞毒性、基因毒性等。在土壤环境中,ZnO NPs可能会对陆地生态系统中的生物构成严重威胁。本研究采用盆栽试验的方法,评估了ZnO NPs对蚯蚓生理以及黄瓜幼苗生长的影响。结果表明:各处理ZnO NPs对蚯蚓的生长发育影响不显著,但随着浓度的增加,蚯蚓的抗氧化酶活性发生变化,SOD呈现出增加的趋势,CAT和POD先降低再上升,二者表现为协同作用。当ZnO NPs处理为1 000 mg·kg-1时,蚯蚓受到的氧化胁迫最大,MDA含量较对照增加了19.2%。对于黄瓜幼苗而言,ZnO NPs处理能够普遍增强植株氧化应激,除了SOD在1 000 mg·kg-1时受到抑制外,SOD、CAT、POD及MDA均随浓度的增加而增加。蚯蚓的加入能显著促进幼苗生长,增加生物量、提高根系活力,同时也能在一定程度上缓解或抑制ZnO NPs对植株造成的损伤。ZnO NPs处理为500mg·kg-1和1 000 mg·kg-1时,SOD分别较不加蚯蚓处理降低了76.7%、63.5%,MDA分别降低了28.6%、23.7%。在28 d培养周期中,蚯蚓对ZnO NPs响应较低,组织锌含量没有显著变化;黄瓜幼苗地上部和地下部锌含量均随着处理浓度的增加而增加,而添加蚯蚓的处理降低了植株的锌含量,也反映了蚯蚓在系统中对胁迫条件下的黄瓜幼苗生长的调控和缓解作用。     

一种氨基酸有机肥降解蔬菜农药残留的效果研究

为验证一种氨基酸有机肥降解农药残留效果,进行不同施用量试验,分析菠菜中农残的降解动态。结果表明,该有机肥对菠菜中毒死蜱、高效氯氰菊酯、百菌清、氧乐果、甲胺磷等5种农药具有较好的促进降解作用;450 ml/666m2 施用量效果最佳,在96 h可以实现高效氯氰菊酯、氧乐果、甲胺磷未检出;该氨基酸有机肥可作为蔬菜绿色高产高效生产的有效手段。     

芸苔素内酯·吲哚乙酸·赤霉酸在不同氮浓度下对小白菜产量和品质的影响

芸苔素内酯·吲哚乙酸·赤霉酸（BHG）对多种农作物增产提质效果显著,但BHG增产提质效果与所处氮水平的关系及相应作用机理尚不清晰。为探讨小白菜产量、品质和有机酸与不同外源氮水平条件下BHG的响应关系及作用机理,采用人工气候室水培法,以小白菜（Brassica chinensis L.,速生绿秀）为试验材料,设1、3、10 mmol·L^-1 3个氮浓度,比较5 μg·L^-1 BHG和清水处理对小白菜生长指标、产量、品质及有机酸、氮磷钾养分、激素含量的影响。3 mmol·L^-1氮水平下,添加BHG显著提高小白菜产量14.87%、可溶性蛋白0.05个百分点、根质量22.95%、根有机酸含量23.89%、钾含量2.64个百分点,ZT/ABA （玉米素/脱落酸）、IAA/ABA （吲哚乙酸/脱落酸）值分别升高97.66%、58.88%。1 mmol·L^-1氮水平下,添加BHG使小白菜可溶性蛋白降低0.04个百分点,糖酸比升高637.86%,ZT/ABA值降低15.19%,IAA/ABA值降低58.36%,根长、根鲜质量降低12.50%、15.16%,但对小白菜产量无显著影响。10mmol·L^-1氮水平下,BHG显著提高小白菜可溶性糖0.09个百分点、有机酸含量12.97%、根长20.84%、根部有机酸36.18%、营养液有机酸16.21%、吲哚乙酸含量17.74%、玉米素含量11.62%、水杨酸含量23.57%,使ZT/ABA、IAA/ABA值分别升高38.50%和46.08%,可溶性蛋白显著降低0.07个百分点,但对小白菜产量无显著影响。研究表明,BHG对小白菜产量、品质的影响与其所处氮水平密切相关,BHG在3 mmol·L^-1氮水平显著增产提质,主要机理为调控小白菜内源激素含量,提高ZT/ABA、IAA/ABA值及根质量和有机酸含量,进而提高小白菜营养元素的积累和利用。     

粤北大宝山矿区污染成因与源头控制技术应用进展

韶关大宝山矿区周边兴起的无序民采和商业矿采活动对山体周边生态环境造成了巨大的破坏,严重威胁到当地居民的生命健康。为应对矿山生态退化、重金属污染及潜在生态环境等问题,矿区有效实施了水体治理和矿山生态环境修复等多项工程。本文在全面调研和搜集大宝山矿区污染现状相关资料的基础上,以清污分流、尾矿清淤、污水处理、植被恢复、矿山环境综合治理等工程实施内容及相关政策为依据,对大宝山矿区部分污染修复工程案例进行总结。并在全面分析矿山污染来源、横石河及其周边农田土壤、地下水的污染现状的基础上,简要归纳矿区目前所施行的治理工程及其成效,主要包括新山片区历史遗留矿山生态修复工程、铁龙新山片区清污分流工程、李屋拦泥库清淤工程以及尾矿库外排水处理厂工程。大宝山矿区采取的相关治理方法和理念可以为其他矿区的生态修复提供参考。     

不同覆膜材料对旱地农田土壤理化性质及春玉米产量的影响

为探索不同覆膜材料对旱地农田土壤理化性质以及春玉米产量的影响,试验设置五种覆膜处理（T1: 0.01 mm普通聚乙烯地膜, T2: 0.01 mm降解地膜, T3: 0.007 mm降解地膜, T4: 0.006 mm降解地膜, CK: 裸地）,研究不同覆膜材料对土壤水热状况、养分含量、以及春玉米产量指标的影响。结果表明：T1和T2处理的0~25 cm土层的土壤温度较其他处理高0.82~6.05℃,0~40 cm土层的土壤水分高于其他处理0.42%~ {4.44% }。在0~20 cm土层中,T2处理的土壤碳、氮含量及腐殖酸含量较其他处理高 {4.69%~ }59.24%。T1和T2处理下春玉米的产量指标和水分利用效率均显著高于CK处理（P＜0.05）。并且T2处理的穗粗和穗粒数最高,秃尖率最低。研究表明,T2处理有助于改善旱地春玉米农田土壤理化性质,增加产量、提高品质,可作为春玉米高产环保栽培的覆膜材料。     

The growth of tagestes erecta,petunia hybrida nana compacta and myosotis alpestris in a range of peat‐based container media

Abstract

The dry matter yield and nitrogen content of marigold (Tagestes erecta), petunia (Petunia hybrida nana compacta) and forget‐me‐not (Myosotis alpestris) plants growing in a range of peat‐based container media amended with different proportions of either sand, perlite, pumice, sawdust, bark chips or soil were studied under glasshouse nursery conditions.

Plant responses differed between species as manifested by their different correlations with measured moisture and aeration characteristics of the media. Marigold and petunia were adversely affected by excessive moisture content as demonstrated by their negative correlation with micropore water and container capacity. However, forget‐me‐not, being adapted to relatively high moisture regimes, responded adversely to increased aeration.     

甘薯脱毒薯特性鉴定及亲本利用评价

 选用目前生产上推广面积较大的几个品种，经多年多点鉴定结果表明，脱毒甘薯不同地点、品种、年份均表现增产，增产幅度为１４．９５％～９１．６１％。甘薯脱毒后干物质含量、抗病性则无明显变化。脱毒薯比非脱毒薯地上部生长旺盛，后期干物质积累优势突出。用脱毒苗作有性杂交亲本比对照结实率略高，植株开花性状、实生后代表现无明显差异。     

细胞转化牛膝的质量分析

本研究用薄层扫描法和原子吸收分光光度法对细胞转化牛膝和天然怀牛膝进行了齐墩果酸和微量元素分析。结果表明，与天然怀牛膝相比，细胞转化牛膝的齐墩果酸含量略低(1．43％)，钙、镁、铜、铁、锌含量明显偏低，而锰含量偏高。