Physiological disorders in tomato and some methods to avoid them

Tomato can be injured by two very important physiological disorders, namely blossom end rot (BER) and fruit cracking (FC). The purpose of this review is to describe these physiological disorders and to assess whether cultivar and cropping system can minimise their symptoms. Physiological Ca deficiency is usually related to the inability of the plant to translocate adequate Ca to the affected plant part, rather than to insufficient Ca levels in the growing medium. The first visible symptom of BER is a small darkened or water-soaked area around the blossom end of the fruit, appearing about the time the fruit begins to ripen. The spot darkens, enlarges, and becomes sunken as the fruit matures. Large lesions may show in concentric rings. FC is the splitting of the epidermis around the calyx or stem scar. FC is a physiological disorder, which mainly occurs when there is a rapid net influx of solutes and especially water into the fruit, while at the same time ripening or other factors reduce the strength and elasticity of the tomato skin. This review article gives an overview of the causes of BER and FC and summarizes growing methods aimed at reducing these physiological disorders of tomatoes.     

Tipburn of Chinese cabbage in relation to calcium nutrition and distribution

Heading Chinese cabbage (Brassica campestris ssp. pekinensis Rupr.) grown with low Ca or B developed dark tan lesions near the leaf margins. A synergistic effect of low Ca and low B accompanied the development of this symptom. Plants grown under humid conditions were free of tipburn. Plants grown under less humidity developed tipburn. Total chemical analysis revealed a steady decrease in total Ca from the outer to the inner leaves. Fractional chemical analysis showed 7 times more water-soluble Ca in the outer than in the inner leaves, and 2 times more 1 N NaCl-soluble Ca in the outer than in inner leaves. Threshold concentration of water-soluble forms of Ca for tipburn was around 3.0 mg/g dry weight. Data suggest that root pressure flow is required to move adequate amounts of water-soluble Ca to the wrapper leaves to prevent tipburn of Chinese cabbage.     

设施环境下蔬菜干烧心的发生原因及防控策略

随着我国设施农业的快速发展,蔬菜生产亟需从数量向质量转型,提高蔬菜质量已成为设施蔬菜发展的首要问题。干烧心是叶菜类蔬菜生产中普遍存在的由钙缺乏引起的生理性病害,在设施环境下尤为严重。本文从蔬菜种类、设施环境（风速、湿度、光环境、营养液）和栽培管理的角度,系统分析了设施环境下蔬菜干烧心发生的原因,并提出了相应的防控策略。     

Relationship between tipburn and leaf mineral composition in strawberry

Malformation of emerging leaves with distortion of leaf tips, a condition known as tipburn, is frequently observed in strawberry. Calcium (Ca) deficiency has been considered the main cause of tipburn. The aim of the present study was to analyse the relationship between leaf mineral composition and the incidence of tipburn in three short-day strawberry (Fragaria x ananassa Duch.) cultivars (‘Ventana’, ‘Camarosa’ and ‘Candonga’) submitted to different concentrations of Ca. The studies were conducted in a hydroponic system in a greenhouse. Calcium was added as Ca(NO₃)₂ at 2 mM, 3 mM, 4 mM and 5 mM. A completely randomized block design (4 Ca concentrations × 3 cultivars) with three replications was used. Each replicate consisted of 12 plants grown in a polyethylene bag (100 cm × 18 cm × 3 cm) filled with coconut peat. Crown diameter and tipburn incidence were evaluated throughout the experimental period, and at the end of the experiment leaf mineral composition was assessed. In general, plants with larger crown diameters had a greater incidence of tipburn. The ‘Candonga’ cultivar had the smallest incidence of tipburn, while the ‘Camarosa’ and ‘Ventana’ cultivars were more susceptible. There was no correlation between level of Ca applied and incidence of tipburn. The incidence of tipburn was associated with foliar K:Ca and K:Mg ratios. Ratios above 3.40 for K:Mg and 1.77 for K:Ca represented a risk of more than 50% of tipburn incidence, when overall means for all cultivars and levels of Ca were used.     

Yield and quality of Corchorus olitorius baby leaf grown in a floating system

Corchorus olitorius is mainly cultivated in Africa and is used in the human diet for its nutraceutical proprieties. In this work, C. olitorius was grown in a floating system using a standard (NS100%) or halved (NS50%) nutrient solution. Yield was evaluated at harvest when plants reached the baby leaf stage. Quality of leaves was estimated by measuring sugars, nitrate, chlorophylls, carotenoids, polyphenols, and anthocyanins. Yield was similar to other common leafy vegetables cultivated in floating systems. Analytical determinations showed good levels of antioxidant compounds and sugars. Mineral contents were relevant for Ca, Mg and Fe in comparison with C. olitorius cultivated in soil and other common leafy vegetables. Results showed these plants had healthy characteristics for human nutrition, in particular for women and children. C. olitorius had a good performance in the floating system with yield ranging from 0.8 to 2.4 kg m^?2. Mineral nutrient levels were higher than in the major leafy vegetables. Nutrient solutions influenced anthocyanin accumulation (+37% in NS50% in spring and +48% in NS50% in summer). Leaf nitrate content was –50% in NS50% at spring cultivation. The overall quality parameters suggest that C. olitorius can be an optimal candidate for baby leaf production in the fresh cut leafy vegetable industry.     

The effect of trickle irrigation,misting and row position on the incidence of tipburn of field lettuce

The effect of trickle irrigation, with and without additional applications of night mist, just before maturity on the incidence and severity of tipburn in field lettuce was investigated. The mean incidence of tipburn for all treatments was much higher (84%) on the outer 2 rows of beds than on the inner 2 rows (47%). On the outer rows irrigation and misting had virtually no effect on tipburn, whereas on the inner rows irrigation reduced it from 72% (in control plants) to 39%, misting to 63% and misting + irrigation to 16%. It is believed that the combination of night misting and trickle irrigation of inner rows resulted in conditions conductive to root-pressure flow which translocated calcium ions to heart leaves of lettuce plants, thereby reducing tipburn injury. It is suggested that the increased severity and incidence of tipburn in the outer rows could have resulted from soil compaction in wheelings which would reduce root growth, soil aeration and root pressure.     

结球莴苣“烧边”成因及其调控措施的研究进展

结球莴苣烧边病是生理性病害，严重影响其品质，制约生产。国内外多数研究者认为钙缺乏导致结球莴苣烧边病的发生，但是现在许多研究表明其他因素也能导致烧边病的出现，例如环境因素、生长速率、内源激素等，所以研究烧边病发生的机制及其与环境因素的关系是防御结球莴苣烧边病发生的关键。     

贮藏温度对叶菜类蔬菜采后品质的影响

本试验以生菜、油麦菜和茼蒿三种菊科叶菜类蔬菜作为试验材料,探讨不同贮藏温度对叶菜采后外观品质、可溶性蛋白质含量、丙二醛含量和相对含水量等生理指标的影响.结果表明,三种叶菜类蔬菜冷藏处理(4℃)的外观及其生理品质都比常温(25℃)处理好,在4℃条件下贮藏,能有效减缓外观品质的变化,降低硝酸盐的积累,抑制叶绿素的分解和丙二...     

娃娃菜干烧心病流行规律及发病因子调查研究

采用田间系统调查、小区试验等方法对甘肃省张掖市娃娃菜干烧心病的流行规律和发病因子进行调查研究。结果表 明：张掖市娃娃菜干烧心病田间发病症状有3 种,即干边型、卷叶型和腐烂型;病叶集中出现在19～40 片叶之间;莲座期 开始发病,莲座期到包心期病害呈缓慢增长态势,结球期病害迅速增长,成熟期病情基本稳定;娃娃菜干烧心病的发生与植 株叶片Ca 含量、品种抗性、氮肥施用量、土壤全盐含量、茬口和种植密度等因子密切相关。     

The effect of boron on tipburn and auxin activity in lettuce

Lettuce plants (Lactuca sativa L.) grown in a boron deficient nutrient medium developed tipburn. Their leaves showed no overall increased auxin activity compared with those of control plants until they were 66 days old, when boron deficient plants showed a relative increase in the activity of one auxin. It is postulated that tipburn in lettuce may be caused by interacting factors including calcium and boron deficiences, and the ontogenetic age of the plant. Environmental and cultivar effects on the incidence of tipburn indicate that agronomic or genetic control measures may become feasible, if the mechanism controlling its expression can be further elucidated.     

Review ArticleInternal tipburn of cabbage (Brassica oleracea var. capitata)

Summary

Internal tipburn of cabbage (Brassica oleracea var. capitata) is a serious quality defect. The discolouring and desiccation of inner head leaves may render whole yields useless. The disorder is regarded as a localized calcium ficiency. The ficiency is not caused by reduced calcium availability to the plant, but rather by calcium transport characteristics within the plant. Because of the absence of transpiration from the inner head leaves of the cabbage plant, calcium is transported to the meristematic tissues in the head mainly by root pressure flow or because of meristematic sink activity during the night. High growth rates are known to increase the incidence of internal tipburn. Probably because of the increased demand for calcium per unit of time, the result of disruption in the calcium transport to the head is more serious. Conditions of even transpiration between day and night, whether high or low, reduce root pressure flow to the head and thereby may induce development of internal tipburn. A combination of high growth rates and low root pressure flow during periods of prolonged dry, sunny weather with high transpiration rates during the day as well as during the night, may be especially important in inducing internal tipburn, because of insufficient calcium influx in the cabbage head under such conditions. As initiation of calcium deficiency in growing tissue is a subcellular process, visible symptoms of internal tipburn may be expressed only later. Growers are primarily advised to cultivate internal tipburn resistant cultivars. Recommendations to limit the occurrence of internal tipburn are formulated.     

叶菜类蔬菜携带蓝色物的反思——科学使用农药,确保农产品质量安全

对市民购买的叶菜类蔬菜携带的蓝色物质进行了分析,发现蓝色物质是防治菜地蜗牛、蛞蝓的杀螺剂的残留,并对这种现象的形成进行了反思,提出了科学使用农药,确保农产品质量安全的建议。     

大白菜干烧心病的形态结构及生理生化变化

以人为诱发大白菜(Brassica Campestris L.ssp.pekinensis(Lour)Olsson.)干烧心病的方法,研究了该病发生发展过程中叶片形态结构及生理生化的变化。结果表明:随着叶片中钙含量的下降,干烧心病症逐渐出现。在此过程中,光合强度降低,膜受损伤,糖含量及电解质外渗率渐增,粘液外溢于叶表;解剖结构观察可见质膜内陷,有囊状小泡形成,细胞器逐步解体;随之,可溶性果胶剧增,胞壁损伤,最后细胞解体死亡,残存固形物充塞了胞壁内外。对叶片排水器黑变与干烧心病发生的独立性检验,表明二者无相关性。     

蔬菜对重金属生物富集程度的初步研究

在农区随机采集蔬菜样品及相应土壤,测定其重金属含量及土壤pH,分析各种蔬菜对重金属的生物富集程度。结果表明,各种蔬菜对不同重金属的生物富集程度有较大差异,叶菜类蔬菜总体富集程度较高;重金属中,各种蔬菜对镉(Cd)的生物富集程度均较高;土壤pH与叶菜类蔬菜对Cd的生物富集程度呈显著负相关。     

EM发酵有机肥对油菜生物性状及重金属含量的影响

采用盆栽定位试验的方法研究了EM菌剂发酵有机肥料与化肥配施对油菜生长及硝酸盐、VC及重金属铅、汞含量的影响。结果表明:在试验范围内,EM菌剂发酵有机肥料与化肥配施,油菜的生物量比对照增加132.0%,VC含量较对照增加36.4%;硝酸盐含量降低20.9%,铅、汞含量分别降低37.4%和36.8%。EM菌剂发酵有机肥料与化肥配施,可以协调土壤生态肥力,降低油菜对重金属和硝酸盐的吸收,改善油菜生长与品质。     

The relationship between leaf growth,calcium accumulation and distribution,and tipburn development in field-grown butterhead lettuce

The change in calcium (Ca) concentration with time, the distribution of Ca within various leaves, and leaf and tipburn development were studied in field-grown lettuce (Lactuca sativa L.) cultivar ‘Cobham Green’.Ca distribution between and within leaves followed two distinct patterns. The average concentrations in the outer leaves were always higher than in the inner leaves. The concentrations at the periphery of the outer leaves was always greater than in the midrib, whereas for the inner leaves the converse was true.Tipburn only occurred in the inner leaves; it developed on only those leaves and those parts of the leaf which expanded most rapidly.Thus, tipburn development appears to depend on the supply of Ca relative to the rate of leaf growth.     

—大白菜干烧心病发生过程中心叶组织Ca^2＋定位及超微结构变化

采用电镜细胞化学技术，研究了人为诱导大白菜干烧心病发生过程中心叶组织细胞的Ｃａ２＋定位和超微结构变化。结果表明，正常植株叶片细胞内钙主要分布于液泡、细胞壁和叶绿体的膜片层结构中；试验处理植株随着缺钙天数的增加，细胞壁膜上的钙被释放沉淀到细胞间隙，叶绿体片层膜上的Ｃａ２＋释放到胞液中。缺钙后期，细胞内钙沉淀明显减少。同时细胞结构改变，质膜内陷，叶绿体膜和内膜系统破坏；随后细胞壁中胶层解体，可见症状出现时，细胞内隔消失，细菌侵入细胞间隙     

家庭阳台蔬菜种植方式的初步探索

以适合阳台栽植的菜心、白菜和芥菜3种叶菜的9个品种为材料,在施肥处理上采用常规管理与水肥一体化两种模式,初步探索了阳台蔬菜在两种栽培模式下的生长和发育状况。试验结果表明,在相同施肥管理栽培模式下,不仅菜心、白菜与芥菜3种蔬菜间的产量存在差异,且相同蔬菜的不同品种的地上部鲜质量也存在差异,但是菜心、白菜和芥菜均一致表现出在水肥一体化栽培模式下的植株地上部鲜质量高于常规管理模式,增幅分别为13.83%~51.60%、34.26%~35.24%、16.36%~26.70%,植株收获期根冠比则均低于常规管理模式。     

水培营养液配方对不同叶菜产量和品质的影响

为了研究不同水培营养液对不同类型绿叶蔬菜产量和品质的影响,寻求适合华南地区叶菜生长的营养液配方,采用穴槽无土栽培种植方式,比较了日本园试配方与霍格兰配方对苋菜、芥菜、菜心、生菜、油麦菜生长情况、产量和品质的影响。结果表明,在所有供试蔬菜种类中,使用日本园试配方的蔬菜产量显著高于霍格兰配方,株高、茎粗、叶宽、叶长等外观品质多数较霍格兰配方更具优势,且日本园试配方处理下油麦菜、菜心和苋菜的VC含量较高。因此,日本园试配方更适合华南地区小型蔬菜生产企业实际生产中单一配肥池培养多种叶菜的生产模式。