Effect of slow-release iron fertilizer on iron-deficiency chlorosis, yield and quality of Lilium davidii var.unicolor in a two-year field experiment

Iron deficiency chlorosis of Lilium davidii var. unicolor is often the case in practice in alkaline soils of northwest region of China. It is difficult to control iron chlorosis because of high cost and short effective work time of conventional iron fertilizers. In this study, a 2-year field experiment was conducted to evaluate the effects of two slow-release fertilizers on the suppression of iron deficiency chlorosis, soil chemical properties, and the yield and quality of L. davidii var. unicolor. Results show that both coated slow-release iron fertilizers and embedded slow-release iron fertilizer effectively controlled iron-deficiency chlorosis. The application of slow-release iron fertilizers significantly increased plant height and chlorophyll content of L. davidii var. unicolor at different growth stages. Furthermore, coated iron fertilizer application significantly increased starch, protein, soluble sugar and vitamin C content of L. davidii var. unicolor, and it also significantly improved total amino acid content, with increases in essential amino acids(Trp, Leu, Lys, Phe, Val, and Thr contents) and in nonessential amino acids(Asp, Glu, Cit, Ihs, Acc, Ala, Pro, and Cys contents). It was concluded that application of coated slow-release iron fertilizer could be a promising option for suppression of iron deficiency chlorosis and deserves further study.

Is magnesium deficiency the major cause of needle chlorosis of Pinus taeda in Brazil?

Needle chlorosis(NC)in Pinus taeda L.systems in Brazil becomes more frequent after second and third harvest rotation cycles.In a study to identify factors contributing to yellowing needle chorosis(YNC),trees were grown in soils originating from contrasting parent materials,and soils and needles(whole,green and chlorotic portions)from 1-and 2-year-old branches and the first and second needle flush release at four sites with YNC on P.taeda were analyzed for various elements and properties.All soils had very low base levels(Ca^(2+),Mg^(2+)and K^(+))and P,suggesting a possible lack of multiple elements.YNC symptoms started at needle tips,then extended toward the needle base with time.First flush needles had longer portions with YNC than second flush needles did.Needles from the lower crown also had more symptoms along their length than those higher in the canopy.Symptoms were similar to those reported for Mg.In chlorotic portions,Mg and Ca concentrations were well below critical values;in particular,Mg levels were only one third of the critical value of 0.3 g kg^(-1).Collectively,results suggest that Mg deficiency is the primary reason for NC of P.taeda in various parent soils in Brazil.

Transmission characteristics of Tomato chlorosis virus (ToCV) by Bemisia tabaci MED and its effects on host preference of vector whitefly

The epidemiology of Tomato chlorosis virus(ToCV)in China is closely associated with its vector whitefly,Bemisia tabaci(Gennadius)MED.However,the transmission characteristics of ToCV by B.tabaci MED remain poorly understood.In this study,we analyzed:1)the horizontal and vertical transmission of ToCV by B.tabaci MED whiteflies;2)the acquisition of ToCV by male and female B.tabaci MED whiteflies after different feeding durations;3)the transmission efficacy of viruliferous male and female B.tabaci MED whiteflies after different inoculation access periods(IAPs);4)the retention of ToCV by viruliferous male and female B.tabaci MED whiteflies after a 48 h acquisition access period(AAP);and 5)the effects of ToCV on host choice of healthy or ToCV-infected tomato plant of viruliferous and non-viruliferous B.tabaci MED at different time points.Our results showed that:1)viruliferous males could not transfer ToCV to non-viruliferous females,and vice versa,viruliferous females could not pass on ToCV to non-viruliferous males.ToCV could not be detected in the F1 generation adults;2)ToCV could be detected within 4.0%of females or males after a 20 min AAP;3)ToCV could be detected in 33.3%of tomato plants inoculated by 10 viruliferous males or females with IAPs of 20 or 30 min;4)the maximum retention time in females was 7 and 5 days in males;and 5)non-viruliferous B.tabaci MED did not show a preference for ToCV-infected tomato plants or healthy tomato plants.However,viruliferous B.tabaci MED whiteflies did prefer to settle on healthy tomato plants over ToCV-infected tomato plants.These findings will be helpful to better understand the epidemiology of the recently emerged plant virus,ToCV,in tomato fields in China.

Diagnosis and treatment of iron-deficiency anemia in gastrointestinal bleeding:A systematic review

BACKGROUND Anemia is considered a public health issue and is often caused by iron deficiency.Iron-deficiency anemia(IDA)often originates from blood loss from lesions in the gastrointestinal tract in men and postmenopausal women,and its prevalence among patients with gastrointestinal bleeding has been estimated to be 61%.However,few guidelines regarding the appropriate investigation of patients with IDA due to gastrointestinal bleeding have been published.AIM To review current evidence and guidelines concerning IDA management in gastrointestinal bleeding patients to develop recommendations for its diagnosis and therapy.METHODS Five gastroenterology experts formed the Digestive Bleeding and Anemia Workgroup and conducted a systematic literature search in PubMed and professional association websites.MEDLINE(via PubMed)searches combined medical subject headings(MeSH)terms and the keywords“gastrointestinal bleeding”with“iron-deficiency anemia”and“diagnosis”or“treatment”or“management”or“prognosis”or“prevalence”or“safety”or“iron”or“transfusion”or“quality of life”,or other terms to identify relevant articles reporting the management of IDA in patients over the age of 18 years with gastrointestinal bleeding;retrieved studies were published in English between January 2003 and April 2019.Worldwide professional association websites were searched for clinical practice guidelines.Reference lists from guidelines were reviewed to identify additional relevant articles.The recommendations were developed by consensus during two meetings and were supported by the published literature identified during the systematic search.RESULTS From 494 Literature citations found during the initial literature search,17 original articles,one meta-analysis,and 13 clinical practice guidelines were analyzed.Based on the published evidence and clinical experience,the workgroup developed the following ten recommendations for the management of IDA in patients with gastrointestinal bleeding:(1)Evaluation of hemoglobin and iron status;(2)Laboratory testing;(3)Target treatment population identification;(4)Indications for erythrocyte transfusion;(5)Treatment targets for erythrocyte transfusion;(6)Indications for intravenous iron;(7)Dosages;(8)Monitoring;(9)Indications for intravenous ferric carboxymaltose treatment;and(10)Treatment targets and monitoring of patients.The workgroup also proposed a summary algorithm for the diagnosis and treatment of IDA in patients with acute or chronic gastrointestinal bleeding,which should be implemented during the hospital stay and follow-up visits after patient discharge.CONCLUSION These recommendations may serve as a starting point for clinicians to better diagnose and treat IDA in patients with gastrointestinal bleeding,which ultimately may improve health outcomes in these patients.

Measuring leaf necrosis and chlorosis of bamboo induced by typhoon 0613 with RGB image analysis

Symptoms of leaf necrosis or chlorosis of bamboo induced by Typhoon 0613 （T0613） were analyzed using RGB image analysis in Yamaguchi city, Japan. Results showed a closely positive relationship between Green/Red （G/R） value for indoor taking images of bam- boo individual leaves and chlorophyll meter value （SPAD） with regression coefficient of 0.961. The relation between G/R value of room taking images and Necrotic Area Percentage （NAP） for bamboo individual leaves showed an inverse logistic function relationship, with the correlated coefficient equaling to 0.958. Both leaf chlorosis and necrosis can be quantitatively estimated by RGB image analysis. Moreover, the variance of Green/Luminance （G/L） value for the same leaf was less than that of G/R for images taken in the conditions with large light difference, especially for green leaves. G/L value also exhibited a closer relationship with SPAD value of leaves with chlorosis than that of G/R values at the same condition. The relationship between G/L value for bamboo canopies and the Distance from Coastline （DC） was also closer than that of the G/R value for the images taken at field sites with big light difference.

Occurrence Reasons and Integrated Control of Physiological Chlorosis ofCinnamomum camphora L. in Urban Area of Pingdingshan City

The relevant factors for physiological chlorosis of Cinnamomum camphora L. in Pingdingshan were studied combining with references and production sur- vey. The resuhs showed that the disease was the integrated results of soil environment, planting situation, microenvironment construction and maintenance manage- ment. Therefore, the countermeasures of ＂prevention first, restore tree vigor; integrated control, enhance tree vigor＂ were proposed. Chlorosis of C. camphora had been basically controlled after four years, and the control effect was obvious.

Manganese toxicity-induced chlorosis in sugarcane seedlings involves inhibition of chlorophyll biosynthesis

Manganese(Mn)toxicity-induced leaf chlorosis limits crop production in acidic soils,but its underlying mechanisms remain unknown.The effects of excessive Mn on chlorophyll(Chl)biosynthesis in sugarcane(Saccharum officinarum L.)leaves were investigated.Under Mn treatment,Chl concentration decreased with Mn accumulation and chlorosis appeared in expanding leaves.Before that,levels of the initial Chl precursor 5-aminolevulinic acid(ALA)and its downstream intermediates decreased,whereas magnesium-protoporphyrin IX monomethyl ester(MgPME)accumulated.Overaccumulation of Mn in leaves downregulated the ALA biosynthetic gene GluTR(encoding glutamyl-tRNA reductase)and MgPME conversion gene MgPMEC(encoding MgPME cyclase),upregulated the ALA biosynthesis inhibitor FLU(encoding FLUORESCENT),but had no significant effect on the expression of other Chl biosynthetic genes.The above Mn-induced changes of Chl precursors and expression of corresponding genes commenced before the Chl decline and leaf chlorosis,and were reversed by ALA supplementation.Thus,excessive Mn-induced chlorosis in sugarcane is mediated by a Chl-biosynthesis disorder resulting from the inhibition of ALA synthesis and MgPME conversion.

Retroperitoneal hyaline-vascular variant Castleman Disease in a patient with iron-deficiency anemia and sinus bradycardia:a case report

Objective Castleman disease, also known as giant lymph node hyperplasia, involves lesions in the lymph nodes usually located in the chest_ENREF_1, particularly in the mediastinum. Meanwhile, sinus bradycardia is a sinus rhythm slower than 60 beats per min, and it can occur in both healthy and sick individuals. However, the comorbidity of these two disorders has not been previously reported. In this paper, we report a case of a 46-year-old woman who presented with persistent sinus bradycardia and irondeficiency anemia. Diagnostic work-up revealed hepatosplenomegaly and a giant mass near the splenic hilum. The mass was removed surgically; after which, the patient's bradycardia resolved immediately, while her anemia was corrected after subsequent chemotherapy. Pathological examination revealed lymph nodes with benign lesions, and the patient was diagnosed with hyaline-vascular variant of Castleman disease. This is the first documented case of sinus bradycardia associated with Castleman disease. In this paper, we describe the case characteristics, discuss the possible pathogenesis, and consider the appropriate treatment of symptomatic sinus bradycardia accompanying Castleman disease.

How Raised Beds and Fe-Chelate Affect Soybean Iron Deficiency Chlorosis and Yield

Water-logging and the inability to take up sufficient iron (Fe), causing iron deficiency chlorosis (IDC) in soybean (Glycine max, L. Merr.), can be major yield reducing factors in certain soils in the northern USA and Manitoba, Canada, soybean growing regions. The objective of this research was to evaluate soybean IDC, biomass production, and yield with seeding on raised beds and seed application of the Fe-chelate compound ortho-ortho-Fe-EDDHA. In six environments, soybean were seeded on raised beds and conventionally prepared seedbeds (flat) and with a factorial arrangement of five cultivars (within adapted maturity group 0.1 to 0.9 and variable IDC tolerance) and seed applied Fe-EDDHA using rates of 0 kg·ha−1 and 3.36 kg·ha−1. There were no significant interactions between the factors tested. The plant population was 27% higher on the raised beds compared with flat, and yield was 6.3% higher (2893 kg·ha−1 vs. 2722 kg·ha−1). Total dry plant biomass on raised beds was 9.8% greater compared with flat. The plant population with seed applied Fe-EDDHA was 10.6% lower compared with no application. However, the IDC score was significantly lower 2.2 vs 2.4 (1 = green, 5 = dead) for Fe-EDDHA seed application. Yield and plant biomass were not significantly different between Fe treatments. Raised beds offer an opportunity for soybean growers to reduce the negative influence of excessive water. Further research is needed to determine the long-term effect of raised beds on plant development, IDC expression, and yield. The application of Fe-EDDHA remains a partial solution and should therefore be combined with other methods to reduce IDC. Further research should study other Fe-EDDHA application rates and methods.

甘蓝型油菜子叶黄化致死突变体BnaC02.YTL的遗传解析

叶绿体相关突变体是研究光合作用、叶绿素生物合成、叶绿体结构发育等生理途径的优良遗传资源,同时作为标记性状在育种中具有一定的应用价值。本课题组发现一个来自恢复系轮回选择群体的子叶黄化致死突变体ytl(yellowing to lethal),突变体发芽出土后子叶一直处于黄化状态,播种9~15天后死亡,前期的研究将一个控制子叶黄化致死性状的位点定位到C09染色体上。表型观测显示,出苗7天后突变体与野生型相比株高与根长存在显著差异,明显偏短。遗传分析表明,该突变体由两对隐性核基因控制。利用单位点分离群体将BnaC02.YTL定位到对应ZS11参考基因组418 kb的物理区间内,结合定量分析与基因序列比对,BnaC02G0055700ZS作为候选基因的可能性较大。本研究为进一步精细定位基因BnaC02.YTL及后续突变体的功能研究奠定了基础。

‘阳光玫瑰’葡萄黄化现象及防治技术

‘阳光玫瑰’葡萄因具有优良的品质和较高的栽培效益,近年来种植面积迅速增加,已成为我国葡萄主栽品种之一。然而在栽培过程中黄化现象时有发生,严重影响了产量和品质。为此,在生产实践基础上,结合前人的研究,本文针对‘阳光玫瑰’葡萄黄化的成因和造成的危害,提出了防治黄化现象的技术措施,以期为‘阳光玫瑰’葡萄生产提供支撑。

大豆铁元素吸收转运和利用生理与分子机制研究进展

铁是植物细胞生命过程中必不可少的微量元素之一,参与呼吸作用、叶绿素生物合成、光合作用等生命过程。土壤中含有大量的铁元素,但是有效铁的利用受到限制,导致植物缺铁,而植株缺铁直接关系到其生长发育和花粉活力及品质形成,进而造成产量损失。解决该问题的重要举措在于提高大豆对铁元素的吸收转运和高效利用。因此,掌握大豆铁吸收转运和利用规律并明确其分子遗传机制是实现大豆铁营养高效的重要前提。铁营养高效性属于数量性状,受多基因控制,基于其相关功能基因研究培育“高铁大豆”是未来热点之一;此外,通过轮回选择和定向选择也可以有效改良大豆的缺铁失绿症。基于此,本文重点阐述了铁元素在大豆体内的作用、吸收、分配和转运及其过剩产生的毒害现象以及铁元素参与大豆固氮作用,缺铁和高铁对大豆生长发育的影响等内容,并综述了国内外大豆铁元素吸收、转运机制和分子调控机理方面的进展及重要科学问题,旨在为大豆铁营养高效利用提供理论信息。

多毛番茄DCL、AGO和RDR基因家族全基因组鉴定及其对番茄褪绿病毒感染和非生物胁迫响应的分析

对多毛番茄全基因组的Dicer-like(DCL)、Argonaute(AGO)和RNA依赖性RNA聚合酶(RDR)基因家族进行生物信息学和表达模式分析,为深入研究DCL、AGO和RDR基因家族在多毛番茄响应非生物胁迫和病毒感染过程中的功能提供参考。以拟南芥DCL、AGO和RDR基因为参考序列,利用本地Perl语言和Pfam、SMART等软件检索多毛番茄LA1777基因组并确定多毛番茄DCL、AGO和RDR基因家族成员。通过ExPASy、GSDS 2.0、MEGA、Tbtools、SWISS-MODEL等工具对多毛番茄DCL、AGO和RDR家族基因进行生物信息学分析。根据非生物胁迫、番茄褪绿病毒(ToCV)处理和实时荧光定量PCR技术分析该类基因的表达模式。从多毛番茄中鉴定得到7个ShDCL、15个ShAGO和6个ShRDR基因,分别分布在第5,7,6条染色体上,其编码的蛋白与其他植物DCL、AGO和RDR结构相似,均含有该家族特有的保守结构域。系统发育分析表明,这些基因被分为4个亚组,与普通番茄之间具有较高的结构和功能相似性。ShDCL2a、ShDCL2c、ShDCL3、ShDCL4、ShAGO1b、ShAGO3、ShAGO4b、ShAGO5、ShAGO7、ShAGO10a、ShAGO10b、ShRDR1、ShRDR2、ShRDR3a、ShRDR6a和ShRDR6b在多种非生物胁迫和ToCV感染后显著上调表达,推测这些基因在非生物胁迫和病毒侵染过程中发挥着重要作用。

铁源和生草种类对猕猴桃植株缺铁黄化矫治效果的影响

以‘脐红’猕猴桃组培苗为试材,采用盆栽法研究了重碳酸盐诱发缺铁条件下2种铁源(Fe-EDTA和Fe-EDDHA)和5个草种(高丹草、紫羊茅、鼠茅草、黑麦草和毛苕子)对猕猴桃缺铁黄化矫治效果的影响。结果表明,与对照相比,诱发缺铁处理植株新叶全铁含量下降,根中活性铁含量升高且氢离子外排减弱,这可能与诱发缺铁处理提高了根际基质pH和电导率但降低了DTPA铁含量有关。较之对照,EDTA铁源的诱发缺铁处理植株叶片SPAD值和Fv/Fm、根体积、茎中全铁和新叶活性铁分配率均下降;而EDDHA铁源的诱发缺铁植株茎全铁含量则升高,有利于地上部积累更多的铁来防止叶片缺铁黄化。在以EDTA为铁源的诱发缺铁基础上,播种高丹草和紫羊茅能够提高叶片SPAD值,但会降低根际基质pH和电导率。播种高丹草还提高了植株根和新叶活性铁及根中全铁含量、新叶活性铁分配率,但降低了植株新叶数、新叶和茎干重、老叶活性铁分配率;而播种紫羊茅则提高了叶片Fv/Fm值和根中活性铁含量。这些结果说明,在重碳酸盐诱发缺铁条件下,施用Fe-EDDHA或播种高丹草和紫羊茅均可有效缓解猕猴桃植株缺铁黄化,这为石灰性土壤上猕猴桃缺铁绿色高效防控提供了科学依据。

基于缺铁诊断指标筛选的猕猴桃叶片黄化诱因分析

[目的]筛选适宜的缺铁诊断指标,据此分析导致陕西关中地区猕猴桃园叶片黄化的主要因子,并利用施肥矫治试验对该因子进行验证,为猕猴桃叶片黄化防控提供理论依据。[方法]在陕西关中地区,依据叶片黄化后土施Fe-EDDHA可以复绿确定了3个缺铁猕猴桃果园,采集当年强旺营养枝顶端第2~3个叶片,共采集不同黄化度叶片64份,缺铁叶片样品的黄化度以SPAD值表征,将SPAD值与5个缺铁诊断指标进行相关分析。在关中地区选择5个健康果园、80个出现不同程度黄化症状的猕猴桃果园,采集叶片样品,将黄化果园叶片按照黄化程度分为绿叶、轻度黄化叶和重度黄化叶,测定12种元素、活性铁和硝态氮含量及SPAD值,并将其与SPAD值进行相关分析。在85个果园各采集1份土壤样品,分析其基础理化性状。选择两个黄化果园进行施肥矫治效果验证。[结果]64份缺铁黄化叶片中,鲜样邻二氮菲浸提铁与其SPAD值的相关性明显高于干样全铁、0.1 mol/L盐酸浸提铁、1 mol/L盐酸浸提铁和鲜样1 mol/L盐酸浸提铁,说明鲜样邻二氮菲浸提铁最适于猕猴桃缺铁的黄化诊断。健康园绿叶和黄化园绿叶中所测的12种元素、活性铁和硝态氮含量均无显著差异。SPAD和邻二氮菲浸提铁含量的顺序为黄化园绿叶>轻度黄化叶>重度黄化叶,而叶片硝态氮、磷、钾和硼含量则相反。轻度和重度黄化叶钙、全铁和锰含量低于绿叶。相关分析表明,猕猴桃叶片SPAD与叶片邻二氮菲浸提铁、全铁、锰和钙含量正相关,而与叶片钾、磷、硝态氮、全氮、硼、铜等含量负相关。随机森林和通径分析进一步表明,与猕猴桃叶片黄化关系最密切的指标为邻二氮菲浸提铁、钾及硝态氮。线性加平台函数拟合表明,邻二氮菲浸提铁5.084 mg/kg是猕猴桃叶片缺铁黄化诊断的临界值。土壤分析结果表明,黄化园土壤pH和碳酸氢根含量均偏高,而速效钾和硝态氮含量均适宜,说明土壤重碳酸盐诱发缺铁很可能是导致叶片黄化的主要原因。与健康园相比,黄化园土壤阳离子交换量偏低,说明叶片黄化还与土壤阳离子交换能力不足有关。施用Fe-EDDHA和蓝铁矿[Fe_(3)(PO_(4))_(2)·8H_(2)O]均可提高叶片SPAD和邻二氮菲浸提铁含量,降低叶片钾和硝态氮含量,从而矫治猕猴桃叶片缺铁黄化。[结论]叶片鲜样中邻二氮菲铁最适于猕猴桃缺铁黄化诊断,其临界浓度为5.084 mg/kg。陕西关中地区猕猴桃园叶片黄化主要是由土壤重碳酸盐诱发缺铁所致,且与土壤阳离子交换能力不足有关;黄化叶中钾和硝态氮的累积是由缺铁造成的。因此,生产上应注意黄化园铁肥的补充和土壤阳离子交换能力的提升。

Efficacy and Safety of Iron Isomaltoside Compared with an Oral Iron Supplement in the Management of Patients with Iron Deficiency Anemia

Objective: To evaluate the treatment outcome of iron isomaltoside compared with an oral iron supplement in the management of iron deficiency anemia (IDA). Methods: The study included patients with IDA who visited the Outpatient Clinic of the Department of Hematology, the Affiliated Hospital of Qingdao University from October 2021 to August 2022 and met the inclusion and exclusion criteria. According to the actual application of iron supplementation, the patients were divided into two groups: iron isomaltoside treatment group and oral iron treatment group. Baseline measurements were collected before the start of treatment, and measurements were collected subsequently at intervals of 1 week, 1 month, and 3 months. The hematological parameters analyzed included Hemoglobin (Hb), Mean corpuscular hemoglobin (MCH), Mean Hemoglobin content (MCH), Mean corpuscular Hemoglobin concentration (MCHC), and Platelet (Plt). Safety data and adverse event profiles were recorded. Results: Intra-group comparisons: After 1 month of treatment, the Hb significantly improved (P 0.05). Inter-group comparisons: The biochemical parameters were significantly improved (P 0.05) in the iron isomaltoside group compared with those in the oral iron group after 1 month of iron supplementation in patients with mild and moderate anemia. Adverse reactions were tolerable for the patients in both iron isomaltoside group and oral iron group. Only 1 patient in iron isomaltoside group developed anaphylactic shock during medication and recovered after aggressive rescue. Conclusions: Iron isomaltoside which increases Hb more rapidly compared with the oral iron supplementation has few adverse reactions and good acceptance.

西府海棠缺铁性黄化病诊断方法的比较

比较不同方法测定的叶片中的铁含量,以期筛选出诊断西府海棠缺铁黄化病的最佳方法,为西府海棠缺铁黄化病的及时诊断与矫治提供依据。以石灰性土壤中生长的缺铁黄化程度不同的西府海棠为试材,采用SPAD-502 Plus叶绿素仪和分光光度法,分别测定不同黄化程度叶片的SPAD值和叶绿素含量,建立SPAD值与叶绿素含量间的拟合方程,并根据相关系数确定两者间的最佳数学模型;用4种方法测定叶片中的活性铁含量:以1 mol/L HCl为提取溶剂分别浸提干叶和鲜叶,原子吸收光谱法进行检测;以1.5%邻菲啰啉(pH 3.0)为提取溶剂浸提鲜叶,分别通过原子吸收光谱法和分光光度比色法检测,同时也测定叶片中的全镁、全锰、全锌和全铁含量。通过单变量线性回归分析,研究全镁、全锰、全锌、全铁及不同方法测定的活性铁与叶绿素含量间的相关关系。结果显示:SPAD值与叶绿素含量间极显著相关,且用单位叶面积表示的叶绿素含量与SPAD值间的相关性高于用单位叶片鲜重表示的叶绿素含量,SPAD值与单位叶面积表示的叶绿素含量间最佳数学模型为二次多项式函数。全镁、全锰和全锌含量与叶绿素含量间无明显相关性,表明该病症与镁、锰和锌元素无关。全铁和以HCl为提取溶剂测定的活性铁含量与叶绿素含量间显著负相关,而以邻菲啰啉为提取剂测定的活性铁与叶绿素含量间显著正相关。因此,以邻菲啰啉为提取剂浸提鲜叶,通过原子吸收光谱法测定活性铁的方法更适于西府海棠缺铁黄化病的诊断。

警惕番茄褪绿病毒在我国的传播和危害

番茄褪绿病毒(Tomato chlorosis virus,ToCV)侵染番茄引起番茄褪绿病毒病。发病植株下部叶片黄化、脉间褪绿、边缘轻微卷曲,叶片光合作用显著降低,果实变小,产量和品质明显下降。该病毒最早于1998年在美国佛罗里达州发现,随后在世界多地陆续报道。我国首先于2004年在台湾报道,2013年又在北京和山东发现并鉴定了该病毒,同时在辣椒上检测到该病毒。ToCV属于长线形病毒科(Closteroviridae)毛形病毒属(Crinivirus)成员,基因组为二分体正义单链RNA,由粉虱传播。经初步调查和检测,ToCV在我国北京、山东、河北、天津等省市相继发生,给当地番茄生产造成了严重危害。ToCV传播迅速,成为我国番茄生产中又一重要病毒,防控形势严峻。基于以上原因,建议有关部门立即采取相应预防和防治措施,组织开展相关研究和攻关,控制该病毒在我国的传播和危害。

植物吸收利用铁的机理

根据植物铁营养的一些研究进展 ,论述了植物对铁的吸收和运输机理以及 HCO- 3 、N。

不同铁制剂对石灰性土壤条件下猕猴桃缺铁黄化的矫治效果

为明确陕西杨凌渭河滩地猕猴桃出现黄化现象的原因,通过对喷施铁制剂矫正效果的比较,筛选出理想的铁制剂用于果树缺铁黄化病防治。以陕西杨凌西桥村出现缺铁黄化的猕猴桃园为研究对象,采用土壤诊断和叶片诊断等方法确定黄化的原因,并以清水为对照,喷施不同铁制剂(硫酸亚铁、柠檬酸铁、复合氨基酸铁、乳酸亚铁和腐殖酸铁)进行矫治,检测其对猕猴桃叶片叶绿素和有效铁含量及果实品质的影响。结果表明,猕猴桃黄化原因不仅仅是由于土壤有效铁含量低,还与植株吸收能力不同有关。由于植株过多吸收P、K、Zn、Mn等元素,引起养分不平衡而导致对铁吸收产生拮抗作用也是产生缺铁黄化的原因之一。不同铁制剂对猕猴桃黄化的矫治效果有差异,其中以柠檬酸铁和复合氨基酸铁的处理效果最好,显著提高了猕猴桃叶片的叶绿素和有效铁含量以及果实中维生素C、可溶性固形物、全铁的含量,有效改善了果实品质。在供试的几种铁制剂中,柠檬酸铁和复合氨基酸铁是矫治果树缺铁黄化的最理想制剂。