Genetic and Agronomic Parameter Estimates of Growth, Yield and Related Traits of Maize (Zea mays L.) under Different Rates of Nitrogen Fertilization

This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha−1) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha−1 plots exhibiting the lowest and highest grain yields of 1238 kg∙ha−1 and 2098 kg∙ha−1, respectively. Variety and nitrogen effects on partial factor productivity (PFPN), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFPN (41.3 kg grain kg−1∙N) and AEN (29.4 kg grain kg−1∙N) were obtained in the 30 kg∙N∙ha−1 plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL−1 spent on N) were obtained in the 180 kg∙N∙ha−1. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.

Cloning, Characterization and Transformation of Methyltransferase 2a Gene (Zmet2a) in Maize (Zea mays L.)

DNA methylation is an important epigenetic regulatory mechanism,it regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s)to DNA.In this study,a novel methyltransferase 2a gene(Zmet2a)was cloned in maize and identified by polymerase chain reaction-base(PCR-base)using a bioinformatics strategy.The Zmet2a cDNA sequence is 2739 bp long and translates to 912 amino acid peptides.The Zmet2a protein revealed that it contains BAH and CHROMO structural domains,is a non-transmembrane protein that is hydrophilically unstable,and has no signal peptide structure.Meanwhile,we verified the biological roles of Zmet2a using transgenic Arabidopsis overexpressing Zmet2a and Zmet2a-knockout maize.Transgenic Zmet2a Arabidopsis thaliana showed highly significant advancement inflowering time,and Zmet2a-knockout maize showed advancement inflowering time,with significant changes in several traits.Altogether,these report the role of Zmet2a in the regulation offlowering time,which will lay a foundation for revealing the biological function and epigenetic regulation mechanism of Zmet2a in the growth,development andflowering of maize.

Response of Varied Levels of Phosphorus on Growth and Yield Performance of Sweet Corn,Zea mays L.

A field experiment was conducted during Kharif season 2019 at Zonal Agricultural Research Station,GKVK,University of Agricultural Sciences,Bengaluru.The soil of the experimental site was red loamy sandy in nature having medium nitrogen,low phosphorus and high potassium content,and was slightly acidic in nature.The treatment consisted of 5 levels of phosphorus viz.T1(50%Recommended Dose of Fertilizer(RDF)P2O5),T2(75%RDF P2O5),T3(100%RDF P2O5),T4(125%RDF P2O5)and T5(150%RDF P2O5)in the presence of static dose of nitrogen and potassium.There were 5 treatments each replicated four times.The experiment was laid out in randomized complete block design.The result showed that application of 150%RDF of P2O5 recorded significantly higher growth attributes viz.,plant height(T5:128.125 cm)and the number of leaves per plant(T5:11.1 at 60 Days after Sowing(DAS)).However,the application of 100%RDF of P2O5 treatment recorded a significantly higher seed yield(T3:296.25 g).

密度与氮肥对关中灌区夏玉米(Zea mays L.)群体光合生理指标的影响

合理的密度是玉米构建良好群体结构、优化群体光合生理功能的基础,适宜的氮肥施用量是玉米进行光合生产的营养物质保障。运用作物群体生理学的方法,采用二次饱和D试验设计,研究了关中灌区夏玉米密度与氮肥耦合和群体光合生理指标的关系及其效应,明确了在关中灌区夏播条件下,在45000-75000株/hm^2的密度范围内,密度与玉米籽粒产量、总干物质积累量（DMA）、吐丝期叶面积指数（MLAI）、总光合势（LAD）、平均作物生长率（CGR）为正相关,在45000-60000株/hm^2的密度范围内,密度与玉米叶片平均净同化率（NAR）为正相关,而在60000-75000株/hm^2的密度范围内,密度与玉米NAR为负相关;在氮素施用量≤600.0 kg/hm^2的范围内,氮素施用量与玉米籽粒产量、DMA、CGR为正相关,在氮素施用量≤260.55 kg/hm^2的范围内,氮素施用量与玉米MLAI、LAD为正相关,与玉米NAR为负相关,而在氮素施用量260.55-600.0kg/hm^2的范围内,氮素施用量与玉米MLAI、LAD为负相关,与玉米NAR为正相关。密度对其影响较大的指标为：籽粒产量、DMA、LAD、CGR和MLAI,影响较小的指标为：NAR;氮肥对其影响较大的指标为：DMA、CGR、籽粒产量、NAR,影响较小的指标为：LAD和MLAI。对籽粒产量和群体生理指标的综合影响效应,密度显著大于氮肥,玉米生产中,尤其要重视合理密植。通过对回归模型的解析,筛选确定了陕单8806玉米在关中灌区夏播中,实现高产的密度与氮肥耦合优化技术方案：合理密度为61713-66177株/hm^2,适宜纯氮施用量为309.88-569.02kg/hm^2。

麦茬处理方式对夏玉米(Zea mays L.)根际生物活性的影响

通过两年3点的大田试验,研究了不同麦茬处理方式(平茬、立茬、除茬)对夏玉米(Zea mays L.)根际生物活性的影响。结果表明:不同麦茬处理的夏玉米根际微生物数量、土壤蛋白酶和脲酶活性均呈先升后降的变化趋势,且在吐丝期达到最大值,但在不同生育时期,不同处理间有所差异,趋势为平茬>立茬>除茬,且苗期差异较大,后期逐渐减小。麦茬处理方式对夏玉米田土壤碳通量的影响也表现出同样趋势。

交联羧甲基复合变性葡聚糖的合成及吸附玉米赤霉烯酮(ZEA)的研究

本文以酵母葡聚糖为原料,选用环氧氯丙烷作交联剂,氯乙酸作羧甲基化试剂,在碱催化条件下合成了交联-羧甲基复合变性葡聚糖。以取代度为试验指标,通过单因素试验和正交试验确定了制备交联羧甲基葡聚糖(CCMG)的较佳条件为:反应温度50℃,反应时间5h,氯乙酸用量3.0g,NaOH浓度50%;在此条件下所得产品取代度为0.5左右。研究了交联羧甲基葡聚糖对真菌毒素玉米赤霉烯酮(ZEA)的吸附作用,结果表明,交联羧甲基葡聚糖对玉米赤霉烯酮具有较好的吸附效果,吸附量达到18.643μg/mgCCMG,高于酵母葡聚糖的吸附量2.296μg/mg。

ZEA与DON联合染毒对CTLL-2细胞凋亡及凋亡相关蛋白Bax、Bcl-2和Caspase3等表达的影响

为了探讨玉米赤霉烯酮(ZEA)与脱氧雪腐镰刀菌烯醇(DON)联合作用对免疫系统毒性影响及其毒理机制,试验以T淋巴细胞株(CTLL-2)为材料,在利用CCK-8试验确定ZEA、DON对CTLL-2细胞联合染毒浓度的基础上,研究了ZEA与DON联合染毒对CTLL-2细胞凋亡及凋亡相关蛋白Bax、Bcl-2和Caspase-3等表达的影响,试验设对照组、ZEA染毒组(5μg/m L ZEA)、DON染毒组(0.5μg/m L DON)、ZEA+DON联合染毒组(5μg/m L ZEA+0.5μg/m L DON),染毒时间为48 h,用流式细胞术检测细胞的凋亡率,Western-blot检测Bax、Bcl-2和Caspase级联反应相关蛋白的表达情况。结果表明:与对照组相比,各染毒组CTLL-2细胞的凋亡率均极显著升高(P<0.01);各染毒组细胞凋亡相关蛋白Bax/Bcl-2比值和Cleaved Cspase-3、Cleaved Caspase-8、Cleaved Caspase-9等蛋白的表达量均较对照组显著升高(P<0.05或P<0.01);联合染毒组呈现协同效应。说明ZEA与DON联合染毒在诱导免疫细胞凋亡方面发挥协同效应,它们共同存在可以发挥更强的免疫抑制效应;ZEA与DON联合染毒诱导CTLL-2细胞发生凋亡的机制与Bax/Bcl-2上调的线粒体通路密切相关。

Embryogenesis,Germination,Structure and Cotyledon Dimorphism of Zea mays Embryo

A series of new cognitions on the morphogenesis of maize ( Zea mays L.) embryo have been obtained with scanning electron microscopy and semi-thin section techniques. 1. The proembryo. The proembryo from zygotic cell divisions may be divided into three parts: proper, hypoblast and suspensor. The suspensor is short and small, and only exists transiently. As to the hypoblast there is a growth belt, which promotes elongation of the hypoblast. Eventually the upper portion of the hypoblast contributes to the formation of the coleorhiza and the remainder dries up, sticking to the end of the coleorhiza. 2. The maize embryo possesses dorsiventrality and cotyledon dimorphism. During early proembryo stage, the dorsiventrality appears in the proper of the embryo. On the ventral side, the cells are small with dense cytoplasm and few vacuoles. On the dorsal side, the cells are larger with lower cytoplasmic density and have more vacuoles. During later proembryo stage, the proper develops into two parts: the ventrum and the dorsurn. The ventrum rises up from the center of the ventral side. The dorsurn is composed of the marginal area of the ventral side and the whole dorsal side of the proper. During young embryo development, the ventrum differentiates into the coleoptile, apical meristem, hypocotyl, radicle and the main part of the coleorhiza. What is more important, the emergence of coleoptile primordium and radicular initials occur at the axis of the proper, then the coleoptile primordium expands from its two ends toward left and right to form a ring, and the endogenous radicular initials expand in all directions to form a conical radicular tip. All these morphogenetic activities of the ventrum follow a bilateral symmetrical pattern. The dorsurn forms the scutellum. primordium. Then the scutellum primordium, expands rapidly toward the left, right, front and back, while thickening itself, so as to make all components originating from the ventrum become hidden in the longitudinal groove of the scutellum. Lastly, the left and right lateral scales emerge from the edges of the longitudinal groove and expand toward the central line of the axis. As a consequence, morphologically, the bilateral symmetry of the ventral side of the embryo is revealed entirely. Morphogenetically, the coleoptile primordium and apical meristem in maize are similar to the coleoptile (apical cotyledon) and apex formation of the nice embryo, so the coleoptile of the maize embryo can also be considered as an apical cotyledon. The scutellum is a lateral cotyledon. These dimorphic cotyledons of the maize embryo originate from the dorsiventrality of the proper. 3. The true morphological structure of the maize embryo is recognized and its developmental stages are established. A maize embryo is a hypocotyl, in which the apical part is the shoot apex (or plumule) with the coleoptile, the central part consists mainly of the hypocotyl with a lateral cotyledon (scutellum), and the basal part is the radicle with coleorhiza. The left and right lateral scales derived from the scutellum overlap at the ventral side, leaving only two little pores at both ends of the seam from which the coleoptile and coleorhiza can be seen. The four sequential stages of maize embryonic development are as follows: (1) proembryo, stage. This stage covers a period from zygotic cell division to the appearance of the dorsum and ventrum. (2) ventrum rapid differentiation stage. (3) scutellum rapid expansion stage. (4) lateral scale development stage (or embryonic envelope formation stage). 4. To obtain a median longitudinal section perpendicular to the ventral surface is crucial for recognizing the genuine morphological structure of the maize embryo.

OSMOTIC STRESS DECREASES THE ACTIVITY OF ATPASE ASSOCIATED WITH THE ROOT CAP PLASMODESMATAIN ZEA MAYS

With light and electron microscopy the substructural change and the ATPase activity of corn (Zea mays L.) root cap cells after short-term osmotic stress were studied. Some spoke-like fine strands originating from the departed periplasm and stretching towards cell wall could be observed even after plasmolysis. By observing the precipitation of ATPase activity product (lead phosphate) at plasma membrane and plasmodesmata, it was found that the fine strands were plasma membrane-lined channels surrounding the cytoplasm and that they still firmly connected to the plasmodesmata during plasmolysis. Compared with the control (unstressed), a sharp decrease of ATPase activity in the plasmodesmata of the stressed cells was observed. Inhibition of energy metabolism in these limited locales would affect the physiological activity, maybe including the regulation of permeability and the change of size exclusion limit (SEL) of plasmodesmata.

Location and Analysis of Introgressed Segments in the Parthenogenetic Progenies of Zea mays×Z. diploperennis by GISH

用来自玉米 (ZeamaysL .)与二倍体多年生类玉米 (Z .diploperennisIltis,DoebleyandGuzm偄ｎ)杂交的孤雌生殖后代同一抗病个体的 4个株系进行了基因组原位杂交 ,用改进的杂交技术获得了近 10 0 %的检出率 ,每一检出片段在同源染色体两成员和每两个姊妹染色单体上均有清晰的信号。

Cloning and Identification of A New Na^+/H^+ Antiporter Gene ZmSOS1 in Maize(Zea mays L.)

[ Objective] The study aimed to clone and identify Na^＋/H^＋ antiporter genes in maize, and provided the information for characterizing the function of such genes in abiotic stress tolerance of maize. Method The in silico cloning, RT-PCR, and bioinformatics analysis were used in this study. Result By in sifico cloning, a plasma membrane Na^＋/H^＋ antiporter gene, named as ZmSOS1 （EMBL accession No. BN001309）, was cloned from maize （ Zea mays L. ）. ZmSOS1 has an open reading frame （ORF） of 3 411 bp which encoded a protein of 1 136 amino acids. By multiple sequence alignment analysis, it showed the predicated peptide of ZmSOS1 were 61% and 82% identities in amino acids to the plasma membrane Na^＋/H^＋ antiporter AtSOS1 and OsSOS1, respectively. The RT-PCR analysis revealed that ZmSOS1 could be significantly up-regulated by salt stress, which indicated ZmSOS1 might play a role in salt tolerance of maize. Conclusion ZmSOS1 is a putative plasma membrane Na^＋/H^＋ antiporter gene and may play a role in abiotic stress tolerance of maize.

IDENTIFICATION OF ALTERNARIOL, ALTERNARIOL MONOMETHYL ETHER AND ZEARALENONE BY PARTICLE BEAM LC/MS

A method for simultaneously analyzing altemariol(AOH), altemariol monomethyl ether (AME) and zearalenone(ZEA) by particle beam LC/MS was established, LC separation was accompiished with a solvent system of methanol and water (80:20 v/v). The followed particle beam LC/MS analysis gave searchable spectra of AOH. AME and ZEA. Application of this technique to analysis of an alternaria culture confirmed the presence of AOH and AME.

Preliminary Phenotypic and SNP-Based Molecular Characterization of Maize (<i>Zea mays</i>L.)-Mexicana (<i>Zea mays</i>SSP. <i>Mexicana</i>) Introgression Lines under Inbred Background of 48-2

Wild relatives possess potential genetic diversity for maize (Zea mays L.) improvement. Characterization of maize-mexicana introgression lines (ILs) is of great value to diversify the genetic base and improve the maize germplasm. Four maize-mexicana IL generations, i.e. BC1, BC2, BC3, and RIL, were constructed under the elite inbred background of 48-2, elite inbred line that is widely used in maize breeding in Southwestern China, and were phenotyped in different years and genotyped with 56110 SNPs. The results indicated that 48-2 had higher phenotypic performances than all the characterized ILs on most of the agronomic traits. Compared with other ILs, BC2 individuals exhibited more similar performance to 48-2 on most traits and possessed the highest kernel ratio (66.5%). Population structure and principal component analysis indicated that BC3 individuals gathered closer to 48-2 and exhibited the lowest mexicana-introgression frequency (0.50%), while BC2 (29.06%) and RIL (18.52%) showed higher introgression frequency. The high level of genetic diversity observed in the maize-mexicana ILs demonstrated that Z. mays ssp. mexicana can serve as a potential source for the enrichment of maize germplasm.

Zea-longa评分与改良Garcia评分应用于针刺治疗CIRI大鼠神经功能缺损评估的研究

目的比较Zea-longa评分与改良Garcia评分用于针刺治疗脑缺血再灌注损伤(cerebral ischemia reperfusion injury,CIRI)大鼠的神经功能缺损评估的稳定性、准确性。方法将60只SPF级SD大鼠随机分为假手术组、模型组、针刺组,每组20只。采用线栓法制备大鼠大脑中动脉闭塞模型,2 h后,将线栓拔出1 cm左右,建立CIRI模型。针刺组针刺“大椎”“百会”“水沟”,每12 h进行1次,共治疗7次。72 h后,分别采用Zea-longa评分与改良Garcia评分进行评价,每组选取10只大鼠行TTC染色,并测定脑梗死面积;分别分析和比较Zea-longa评分和改良Garcia评分与脑梗死面积的相关性。结果CIRI术后,大鼠均表现有一定程度神经功能的缺损症状,脑组织TTC染色可见脑梗死病灶。针刺治疗能显著减少脑梗死面积(P<0.05),并改善神经功能(P<0.05,P<0.01)。相关性分析发现,改良Garcia评分与脑梗死面积的r值为-0.647(P<0.01),而Zea-longa评分与脑梗死面积的r值为0.575(P<0.01);针刺与改良Garcia评分及脑梗死面积三者相关性分析r值为-0.522(P<0.05);而针刺与Zea-longa评分及脑梗死面积r值为0.495(P<0.05)。结论改良Garcia评分与Zea-longa评分均可用于CIRI评价研究及针刺疗效评估。在对CIRI大鼠进行感觉功能相关研究时可优先采用改良Garcia评分,偏向运动功能评估时可考虑与Zea-longa评分联合使用,能够比较全面地反映模型大鼠神经功能损伤的严重程度和治疗后的神经功能的恢复程度。

黄芩对ZEA暴露雌性小鼠抗氧化能力、性激素水平和ERαmRNA表达的影响

【目的】试验旨在研究黄芩(SBG)对玉米赤霉烯酮(ZEA)暴露幼龄雌性小鼠抗氧化能力、性激素水平及雌性生殖器官中雌激素受体α(ERα)和孕酮受体(PR)基因表达的影响。【方法】试验选取50只雌性小鼠,预饲1周后随机分为5组,每组10只。对照组(CK)灌胃10 mL/kg玉米油、ZEA组灌胃20 mg/kg ZEA、ZEA+SBG10组灌胃20 mg/kg ZEA+10 g/kg SBG、ZEA+SBG20组灌胃20 mg/kg ZEA+20 g/kg SBG、ZEA+SBG30组灌胃20 mg/kg ZEA+30 g/kg SBG。所有试验小鼠均饲喂基础饲粮,正试期3周。正试期间每日记录小鼠体重;分别在试验的第1、2和3周末晨饲前采集小鼠尾静脉血样,检测血清中抗氧化相关指标和性激素含量;在试验第3周末,采集卵巢和子宫,检测相关类固醇激素受体基因mRNA的表达。【结果】与CK组相比,ZEA暴露2周以上可引起雌性小鼠体重、血清谷胱甘肽过氧化物酶(GSH-Px)活性、谷胱甘肽(GSH)和雌二醇(E 2)含量均显著降低(P<0.05);卵巢刺激素(FSH)水平显著增加(P<0.05),而黄体生成素(LH)水平无显著变化(P>0.05)。与ZEA组相比,20和30 g/kg SBG处理3周均显著提升小鼠体重(P<0.05),20 g/kg SBG处理3周显著升高血清总超氧化物歧化酶(T-SOD)、GSH-Px活性及GSH水平(P<0.05),30 g/kg SBG处理2周后这3项指标均显著提高(P<0.05);20和30 g/kg SBG处理2周显著降低血清丙二醛(MDA)含量(P<0.05);30 g/kg SBG处理2周可显著增加血清E 2水平(P<0.05),显著降低FSH含量(P<0.05);20和30 g/kg SBG处理3周后小鼠子宫和卵巢ERα基因表达显著提升(P<0.05),但PR的mRNA表达量在各组之间差异不显著(P>0.05)。【结论】SBG可通过提高ZEA暴露雌性小鼠血清抗氧化能力及性激素水平,增强子宫及卵巢ERα的表达,缓解ZEA造成的氧化损伤和生殖毒性,SBG推荐剂量为20~30 g/kg。

不同玉米(Zeamays)品种对镉锌积累与转运的差异研究

选取20个玉米(Zea mays)品种作试验材料,通过田间试验研究了镉-锌(Cd-Zn)复合胁迫下玉米的生长发育及其积累和转运Cd、Zn的差异,以期筛选出Cd、Zn低积累的玉米品种。结果表明,Cd-Zn复合胁迫下,玉米的株高、叶面积、生物量、产量以及玉米根、茎叶和籽粒中Cd、Zn含量在品种间均表现出显著差异。有2个品种籽粒的Cd含量超过国家食品卫生标准(≤0.2 mg·kg-1),13个品种茎叶的Cd含量超过国家饲料卫生标准(≤0.5 mg·kg-1),所有品种籽粒和茎叶的Zn含量均符合国家食品卫生标准(≤50mg·kg-1);有7个品种的Cd富集系数<1,13个品种茎叶转运系数<1,所有品种籽粒转运系数均<1;20个玉米品种Zn的富集系数均<1,有18个品种茎叶转运系数<1,6个品种籽粒转运系数<1。根据玉米生物量、产量、籽粒Cd和Zn含量、富集系数、转运系数等指标进行评价,认为红单6号、红育1号、云优78、平单2号、屏单2号5个品种可作为Cd低积累玉米品种,雅玉98可作为Zn低积累玉米品种,可分别在个旧地区Cd、Zn中、轻度污染土壤上推广种植。

不同钝化剂及其组合对玉米(Zea mays)生长和吸收Pb Cd As Zn影响研究

选取硅藻土、生物炭、沸石粉、石灰及其组合开展田间试验,研究它们对玉米（Zea mays）生长、玉米籽粒吸收Pb、Cd、As、Zn与土壤有效态Pb、Cd、As、Zn的影响。结果表明,除石灰粉外,施用其他3种钝化剂及其组合均能促进玉米生长,增加玉米株高、叶面积和生物量,显著提高玉米产量。4种钝化剂及其组合可升高土壤的p H值和降低土壤中的有效态Pb、Cd、As、Zn含量,与CK处理相比,施用不同改良剂导致土壤有效态Pb降低6.82%～20.46%,有效态Cd降低12.76%～28.28%,有效态As降低26.89%～48.74%,和有效态Zn降低13.88%～28.95%,其中BZD（生物炭＋沸石粉＋硅藻土）处理降低效果最明显,BLD（生物炭＋石灰粉＋硅藻土）处理次之;4种钝化剂及其组合都能降低玉米籽粒对Pb、Cd、As、Zn的吸收,其中BZD处理能明显降低玉米籽粒中Pb、Cd、As、Zn含量,较对照分别降低47.71%、95.00%、90.90%、31.41%。在原位钝化修复镉-砷-锌复合污染农田土壤时,BDZ组合的施用效果最佳。

田间条件下不同组配钝化剂对玉米(Zea mays)吸收Cd、As和Pb影响研究

选取4 种钝化材料（硅藻土、生物炭、沸石粉和石灰）开展田间试验,研究不同配施处理对玉米（Zea mays）籽粒吸收Cd、As 和Pb 与土壤有效态Cd、As 和Pb 的影响,以期筛选出钝化修复效果最佳的组配钝化剂.结果表明,（1）施用钝化剂均能有效促进玉米生长,增加植株株高、叶面积、玉米地上部与地下部质量,显著提高玉米产量.（2）不同处理均能明显降低土壤Cd、As 和Pb 有效态含量.其中,BLD 处理对土壤有效态Cd 降低效果最明显,YR＋BLZ 处理次之,与对照相比,土壤有效态Cd 分别降低71.00%和67.85%;BDZ 处理对土壤有效态As 含量降低效果最明显,其次为BLD 处理,较对照分别降低65.63%和59.73%;YR＋BLD 处理对土壤有效态Pb 含量降低效果最好,BDZ 处理次之,有效态Pb 含量较对照分别降低70.64%和69.64%.（3）不同处理对玉米籽粒吸收和积累Cd、As 和Pb 产生不同程度的影响.与对照相比,不同处理导致玉米籽粒Cd 含量降低82.63%~89.17%,As 含量降低27.58%-49.47%和Pb 含量降低9.64%-46.86%.（4）施用钝化剂均能显著提高土壤pH 值,其中BLD、YR＋BLD、JD＋BLD 处理的pH 值升高效果最为明显,较对照分别提高1.05、1.04 和1.04 个单位;施用钝化剂能显著提高土壤有机质含量,YR＋BDZ 和YR＋BLD 处理有机质含量较高,较对照分别提高54.68%和46.04%,本试验结果表明,在钝化修复镉砷复合污染的旱地土壤时,低累积玉米品种与组配钝化剂联合使用能够获得较好的修复效果.

玉米(Zea mays)对镉积累与转运的品种差异研究

通过田间实验，研究了25个玉米（Zea mays）品种在Cd质量分数为50 mg·kg-1胁迫条件下，Cd对不同玉米品种生长的影响，以及不同玉米品种对Cd积累和转运的品种差异，以期筛选出Cd低积累玉米品种。结果表明：25个玉米品种的生物量和产量对Cd胁迫的响应，以及不同品种根、茎叶和籽粒对Cd的吸收、累积及转运能力存在显著差异（P＜0.05）。有20个品种生物量和19个品种产量下降；有2个品种籽粒的Cd质量分数超过了国家规定的食品卫生标准（≤0.1 mg·kg-1），占供试品种的8.0%，所有品种茎叶的Cd质量分数均超过了国家规定的饲料卫生标准（≤0.5 mg·kg-1），超标率为100%；25个玉米品种的富集系数范围为0.063~0.899、茎叶转运系数范围为0.038~0.554、籽粒转运系数范围为0.000~0.111，均小于1，其中有8个品种富集系数〉0.5，1个品种茎叶转运系数〉0.5，而所有品种的籽粒转运系数均〈0.5，说明玉米对土壤Cd仍有一定的吸收能力，但地下部向地上部转运能力以及由茎叶向籽粒的转运能力较弱；根据玉米生物量、产量、籽粒Cd含量以及对Cd的富集系数和转运系数等指标进行评价，认为云瑞8号、会单4号、路单7号3个品种可作为Cd低累积玉米品种，可在云南Cd重度污染土壤上推广种植。

基于分期播种的气候变化对东北地区玉米(Zea mays)生长发育和产量的影响

利用在东北地区中部开展玉米(Zea mays)分期播种试验资料,分析气候变化对玉米出苗速度、生长发育速度、灌浆过程、植株干物质积累和产量的影响,进而分析未来气候变化对东北地区玉米生产的影响及适应性对策。结果表明,气候变化对玉米生长发育和产量的影响十分明显,在水分基本适宜的条件下,东北地区气候变暖导致玉米生长季气温升高、积温增加,使玉米生长发育和灌浆速度加快,生物量增加,从而提高单产。但气候变暖的同时,气候变干会限制热量资源的利用,将缩短玉米灌浆时间,降低灌浆速率,使千粒重下降,从而造成明显减产,而且减产幅度明显大于温度升高的增产幅度。在水分条件基本得到满足的条件下,未来夏半年气候变暖对东北地区玉米生产是有利的,偏晚熟玉米品种比例可以适当扩大,东北玉米带可以向北部和东部扩展,单产和总产都会增加;但如果水分得不到满足,气候的暖干化趋势会使东北地区的中、西部玉米主产区的农业干旱变得更加严重且频繁,造成产量下降和不稳定,给玉米生产带来严重威胁,因而更应加强农业干旱的综合防御工作。