土壤重金属污染对上海青根伸长的抑制效应研究

以上海青种子和3种不同土壤介质为材料,研究重金属Cu、Zn、Pb、Ni单一污染和复合污染对种子发芽率及芽长与根伸长的生态毒性效应。结果表明:同一浓度下,上海青种子发芽率、芽长和根伸长对重金属的生态毒性敏感程度依次为:根伸长>芽长>发芽率;重金属对上海青根生长的生态毒性大小顺序为:Ni>Cu>Zn>Pb;土壤pH与上海青根伸长抑制率的相关性不显著,土壤中有机质和养分对重金属污染有重要的缓冲作用。重金属复合污染对上海青的毒性效应多表现为协同作用。     

银川阅海湿地沉积物重金属潜在生态危害评价

为确定银川市阅海湿地湖水底泥中重金属的污染状态及潜在的生态危险,笔者采集了该湿地底泥,分析了8种常见重金属(As、Cd、Cr、Cu、Hg、Ni、Pb、Zn)的含量及富集情况,又以现代工业化前正常颗粒底泥中重金属含量的最高背景值和自然背景值为参比值,对湿地底泥重金属的富集系数、生态危害系数及各采样点的生态危害指数进行探讨,最后运用Lars Hankanson潜在生态危害指数法对湿地底泥中重金属的生态危害程度做了评价。结果表明：以现代工业化前正常颗粒底泥中重金属含量的最高背景值为参比值,阅海湿地重金属富集顺序为Cr＞Pb＞Zn＞Cu＞As＞Cd＞Hg;各重金属单因子生态危害程度为Cd＞As＞Hg＞Pb＞Cu＞Cr＞Zn,其中4号采样点的重金属潜在生态危害程度较高,其他采样点生态危害程度较轻微。总而言之,银川市阅海湿地底泥重金属的生态危害程度还是较小的。     

海口市城郊蔬菜基地重金属含量分布与评价

采集了海口市城郊3大蔬菜基地8种叶菜类蔬菜共153个代表样及其相应的根系土样品,以土壤环境质量标准(GB15618-1995)和食品安全标准(GB2762-2012)为土壤和蔬菜中重金属限量标准,用 Nemerow综合污染指数和Hakanson潜在生态指数2种评价方法对其进行了评价。结果表明,基地土壤的重金属有效性不大,属于安全、轻微生态危害水平,但Cd的生物潜在有效性较高,对农作物污染风险大。蔬菜对土壤中重金属的富集能力大小为Zn＞Cd＞Cu＞Hg＞As＞Pb＞Cr。所有蔬菜样品中的重金属含量除了Cd外均无超标,其中旱菜Cd超标最严重,超标率达70%,超标倍数最高为0.21。     

长春地区土壤中重金属含量及其在玉米子粒中的积累规律

对长春地区部分农田土壤及玉米中重金属含量进行调查和分析。结果表明,研究区域内土壤中Cu、Zn、Ni、Pb、Cd、Cr、Hg、As 8种重金属含量符合土壤环境质量标准的要求;相应地块玉米中Cu、Zn、Pb、Cd、Cr、Hg、As 7种重金属含量符合粮食重金属元素限量要求,达到食用标准;土壤和玉米中Pb、Cd、Hg含量相关性不显著,Ni、Cr、As含量相关性显著,Cu、Zn含量相关性极显著。     

镉、铅及其复合污染对小麦种子萌发的影响

为了明确重金属对作物种子萌发的影响,采用水培方法研究了镉(Cd)、铅(Pb)及其复合污染对小麦种子萌发的影响.结果表明,低浓度Cd2+、Pb2+单一处理对小麦种子发芽率、发芽势、发芽指数、活力指数及根长均有一定的促进作用,随着处理浓度的提高其数值逐渐下降.低浓度的Cd2+、Pb2+复合处理对小麦种子发芽势及根长均有一定的促进作用,随着处理浓度的提高其数值逐渐降低.Cd2+、Pb2+复合处理对发芽指数及活力指数具有抑制作用.而Cd2+、Pb2+及其复合污染对芽长产生抑制作用,并且随着处理浓度的增加其抑制作用逐渐上升.Cd2+单一处理对小麦种子萌发的毒性最大,其次是复合处理,最小的是Pb2+单一处理.     

玉米植株对重金属的富集与分布

从湛江市赤坎区文章村的玉米园中采集玉米植株及其生长的土壤样品,采用原子吸收光谱法测定铬(Cr)、铅(Pb)、镍(Ni)、铜(Cu)、锌(Zn)5种重金属元素的含量,对玉米不同器官积累重金属的特性进行了初步研究。结果表明,①玉米园土壤受重金属Cr的中度污染;②玉米对土壤中5种重金属的平均富集系数大小顺序为Ni>Pb>Zn>Cr>Cu,其中,Ni、Pb、Zn的富集系数分别为2.411、1.892和1.139;③玉米地上部重金属含量大于根部该种重金属含量。各种重金属在器官中的分布规律不一致,玉米茎中的重金属含量偏高,玉米根中的含量较低;④玉米对土壤Cr元素有较强的避性。     

武夷山市区土壤重金属积累及5种阔叶树富集特征

采集武夷山市区香樟、广玉兰、紫薇、悬铃木和杜英5种行道树叶片及土壤样品,检测Cu、Zn、Ni、Cr和Pb共5种重金属含量,并运用多元统计法分析土壤重金属成因及5种树种的重金属富集系数。结果表明:研究区土壤重金属Cu、Zn、Ni、Cr和Pb存在不同程度的富集,分别是福建省土壤元素背景值的3.3、4.7、2.6、6.1和2.7倍;5种树种叶片的重金属含量有显著差异,广玉兰对重金属富集能力显著,可成为武夷山市行道树主力。     

广东某矿区周边土壤与植物重金属的研究与分析

目前矿区土壤的重金属污染问题引起了世界范围的高度关注。对广东省内某一矿区周边耕地土壤中重金属的污染现状进行调查,采集了矿区周围耕地芭蕉、水稻、玉米、黄豆、番薯及对应土壤,参照《土壤农业化学分析方法》进行重金属含量测定。结果表明:作物样及其对应土壤都受到了重金属Cd、Pb、Cu、Zn的污染,其中污染程度最高的是Cu,综合污染指数法评价表明,4种土壤的综合污染指数都大于2,整体属于中度污染,芭蕉土的综合污染指数超过4,属于严重污染。玉米、芭蕉、番薯的重金属含量处于较高水平,对重金属有一定的富集作用。可见,采矿会对周边土地造成不可忽视的重金属污染。     

青岛市花生产地土壤环境质量的现状分析

对青岛市花生产地土壤重金属Cd、Hg、As、Pb、Cr、Cu、Zn和Ni的含量进行了调查分析,并采用单项质量指数与综合质量指数相结合的方法对环境质量状况进行了评价。结果表明各重金属的平均含量均低于“食用农产品产地环境质量评价标准”（HJ 332-2006）规定的限值,土壤环境质量定为1级,属于清洁水平,适宜发展无公害花生。但莱西一个监测点的土壤样品重金属Cu、Ni含量超标。若以国家土壤自然背景值为标准,Cu的超标率增加了将近3倍,表明Cu在土壤中已经产生了一定的积累。Hg与As的含量呈显著负相关（P ＜0.05）,Hg和Ni、Cr与Cu之间呈显著正相关（P ＜ 0.05）,其它元素之间的相关性未达到显著水平。推测个别元素超标的情况仅属于点源污染,不会引起复合污染。青岛市3个花生优势产区莱西、平度、即墨土壤重金属的环境质量均属于1级,适宜作为无公害花生的生产基地。     

广州某农场土壤和植物重金属含量及健康风险评估

以广州某农场中的植物和土壤为研究对象,采用火焰原子吸收分光光度法对植物和土壤中的6种重金属(Pb、Cu、Ni、Zn、Cr、Cd)含量进行分析,对蔬菜中重金属的人体健康风险进行了评估。结果表明:与国家土壤质量II级标准GB15618-1995(6.5p H7.5)相比,所有土壤样品都超过土壤环境质量一级标准。用单因子指数法、内梅罗污染指数法评价了广州某农场中植物、土壤重金属污染程度,单因子评价结果表明,香蕉土中的Cd和Zn为轻微污染;从内梅罗指数评价中可看出芋头土和豆角土为清洁,小白菜土、毛豆土、番薯土为尚清洁,而香蕉土轻度污染。土壤中Zn元素含量最高,Cd元素含量最低,且土壤重金属含量基本上都高于植物。运用THQ(Target Hazard Quotients)靶标危害系数方法进行健康风险评估,结果表明Cr元素对人体健康造成的影响不明显,Pb、Cu对几类人群健康都存在最大的风险。     

小麦花药伸出特性的QTL分析

花药伸出特性直接影响小麦的授粉结实率和穗部真菌病害抗性,为挖掘控制小麦花药伸出特性的QTL,以半闭颖品种周8425B和开颖品种小偃81构建的包含102个株系的F_2:12RIL群体为材料,于2019和2020年各分两个播期种植于西北农林科技大学小麦试验站,以小麦花药伸出率和视觉花药伸出等级两个性状表型值对4个环境下的花药伸出特性进行表型鉴定,并利用90K芯片构建的高密度遗传连锁图谱进行QTL定位。结果共检测到8个控制花药伸出特性的QTL,分布在3A、3B、5B、6B、6D和7A染色体上,其中6B和6D染色体上各有2个QTL。 QAe.nwsuaf-3A、 QAe.nwsuaf-3B和 QAe.nwsuaf-6B位点在多个环境中均能被检测到,表型变异解释率分别为3.65%~10.48%、8.12%~26.09%和3.49%~8.93%。     

玉米花粉管伸长的时空进程

以玉米花丝为材料,采用苯胺蓝染色法检测授粉后玉米花粉管的伸长进程。授粉0.5 h后开始每隔1 h对花丝取样,直至48 h;所取花丝经固定、软化和苯胺蓝染色后压片,在倒置荧光显微镜紫外光滤片下观测花粉管伸长情况。结果表明,花粉在授粉后0.5 h就开始萌发,随后花粉管开始伸长并逐渐加速,3 h后以较高速度0.8~0.9 cm/h伸长,维持17 h后速度开始下降,22 h后大部分进入子房,整个过程中花粉管的平均伸长速度为0.68 cm/h。玉米花粉离体自然条件下的生命时间为5 h,此后开始分解。在玉米花粉介导转基因时需对离体的花粉与外源基因进行处理,这个过程消耗花粉部分内容物和能量,且影响花粉的活力,是玉米花粉介导法转化率偏低的一个重要原因。     

红地球葡萄花序拉长试验

红地球葡萄生产上需要拉长花序,才能实现优质栽培。通过选择生产上常用的药剂开展田间试验,并进行统计分析,本试验已筛选出两种药剂及其最佳使用浓度。     

甘蔗茎伸长量与土壤水分含量的相关性

为了研究甘蔗各层土壤水分对甘蔗茎伸长量的影响,利用2009-2011年柳州市农业气象试验站甘蔗生育状况观测数据及同期的0～50cm各层土壤水分数据(土壤重量含水量、土壤相对湿度、水分总贮存量和有效水分贮存量),利用Excel软件对甘蔗蔗茎旬伸长量与0～50cm各层土壤水数据进行统计回归分析.结果表明:2009-2011年旬甘蔗伸长量与20～30cm土壤水分关系最密切,呈极显著正相关,其次是30～40cm土层、10～20cm土层、0～10cm土层和40～50cm土层.有效水分存量与甘蔗生长关系最密切,其具有很好的指标作用.     

水稻中胚轴伸长机制研究进展

水稻中胚轴是胚芽鞘节与胚根着生点之间的部分,中胚轴伸长是直播水稻出苗的重要特征。从遗传背景、直播条件、植物激素、细胞结构、基因定位等方面综述了水稻中胚轴伸长机制的研究进展,为直播稻品种的选育和应用提供参考。     

Modeling of Shoot Elongation and Leaf Appearance in Potted Mulberry

Summary

To predict mulberry growth, modeling of shoot elongation and leaf appearance of potted mulberries was attempted. Potted mulberries were grown in temperature-controlled phytotrons. Changes in the rates of mulberry shoot elongation and leaf appearance, and the relationship between the rates and temperature were investigated. The rate of shoot elongation increased until the shoot length reached about 100cm, and became stable thereafter. The rates of both shoot elongation and leaf appearance increased with the increase in temperature from 15°C to 27°C, but not at higher temperatures. However, the rate of leaf appearance increased with the rise in temperature up to 31°C. On the basis of these results, the shoot elongation and leaf appearance of mulberry in phytotron were simulated in non -linear regression models. The relationship between the rate of shoot elongation and temperature, and the rate of leaf appearance and temperature in the model fitted to measured values very well, and that between the rate of shoot elongation and shoot length in the models tended to be in accordance with the measured values. Shoot length and leaf number predicted by the model were in concurrence with the measured values.     

Paper New Allele of HL6 Regulates Trichome Elongation in Rice

Trichomes are specialized epidermal cells that play multiple roles in plant development. However, knowledge about the molecular mechanism of trichome development in rice is limited. In this study, a hairy leaf locus HL6 ^SWWR of rice variety Suwangwanger (SWWR) was identified by map-based cloning. Transgenic complementation and knock-out mutation demonstrated that HL6^SWWR regulated trichomes on leaves and expression levels of HL6^SWWR affected trichome elongation. Transgenic experiments of PRO^SWWR:HL6^NIP and PRO^NIP:HL6^SWWR indicated that the promoter and coding sequences of HL6^SWWR were indispensable for trichome regulation. Sequencing alignment of the promoter and coding regions of HL6 in 22 varieties showed that some cis-binding elements in the promoter region may be related to trichome development, while no decisive variation was found in the coding sequence. Furthermore, RNA-sequencing analysis revealed that 1 415 differential expression genes (DEGs) were detected in hl6^SWWR mutant vs wild type and that 1 010 DEGs were found in HL6^SWWR complementary transgenic line vs wild type. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that most of the DEGs were involved in metabolite pathway, secondary metabolite biosynthesis, plant pathogen interaction and phytohormone signal transduction in both the two groups. The results indicated that these enhanced pathways are critical during trichome development in rice. Taken together, our results provided new views into the regulatory mechanism of trichome formation in rice.     

Elongation Ability of African Floating Rice (Oryza glaberrima Steud.)

Summary

The effect of fluctuation in soil moisture on the root development of sweetpotato was studied during its establishment period, i.e., from planting to about one month after planting. The number of leaves, shoot dry weight and vine length were suppressed significantly by deficient moisture but the same were markedly increased by excessive moisture regardless of the time of occurrence relative to the initial development of the plant. In terms of its roots, the number and total length of the root system components were either increased or decreased depending upon the soil moisture regime in which they were subjected immediately prior to the time of sampling. Deficient soil moisture reduced the number and total length of the root system components while excessive moisture caused notable stimulation. Continuous exposure to normal soil moisture caused substantial reduction in the number of adventitious roots and consequent depression in total length but this could be attributed to sink competition among adventitious roots. Under fluctuating soil moisture, normal moisture content appeared to restore the aberrant development of the roots caused by deficient or excessive levels. The suppressed formation and elongation of the root system components under deficient soil moisture was alleviated when the soil moisture condition was changed to normal. On the other hand, the stimulated root formation and elongation in the excessive moisture was abated when the normal soil moisture condition prevailed afterwards. The result was the opposite when the soil moisture condition was reversed, i.e., normal then followed by either deficient or excessive soil moisture.