The freezing characteristics of cauliflower curd

Cultivar differences in frost resistance and the heritable nature of resistance were demonstrated using seedling cauliflower plants. Such cultivar differences were not however expressed in the curd. Selection for frost resistance in cauliflower should therefore use whole plant screening techniques. Curd material when frozen as isolated florets, supercooled over the range – 1°C to – 12°C and the mean freezing point of all curds tested was -6°C to -7.25°C (overall mean -6.44°C). Curd florets which supercooled but did not freeze were completely undamaged, whereas freezing always led to cell damage and death observed as water-soaking of the floret surface and measured using an electrical conductivity method. The large range of freezing points measured suggests a range of active ice nucleators either on or within the florets. When curds were frozen intact the ability of florets to supercool was severely restricted which was attributed to the seeding of freezing by the internal growth of ice crystals. A crop protection strategy needs to identify and control or modify warm temperature nucleators in cauliflower curd.     

Explaining curd and spear geometry in broccoli, cauliflower and `romanesco': quantitative variation in activity of primary meristems

Brassica oleracea L. is highly polymorphic and includes varieties which exhibit a headed phenotype (a large preinflorescence): the curd of cauliflower and `romanesco' (var. botrytis), and the spear of broccoli (var. italica). This headed phenotype results from highly iterative patterns of activity at the primary meristems. Differences in the morphology of curds and spears are accounted for by three quantitative variables: the rate of production of branch primordia on the flanks of the apical meristems (RPP); the number of branch primordia produced before the first formed begin producing their own branch primordia (the iteration interval, ITI); and the duration of the preinflorescence stage (before production of flower primordia). Relatively stable iteration parameters (RPP and ITI) during curd development lead to the production of semi-spherical curds with a smooth surface in cauliflower and broccoli, whereas in `romanesco' RPP and ITI increase throughout curd development, inducing a pyramidal curd with an angular surface. A relatively long preinflorescence stage in cauliflower and `romanesco' results in the curd surface being composed largely of branch primordia, whereas in broccoli this stage is short and the spear surface is made up of flower buds. Simplified growth models for these three headed types are presented. The implications for the genetic control of the B. oleracea L. headed phenotype and the relationships between shoot apical meristem size, phyllotaxis and curd/spear morphology are discussed. Received: 11 September 1997 / Accepted: 12 November 1997     

Fern leaves and cauliflower curds are not fractals

The popular demonstration of drawing a mature fern leaf as expressed by Barnsley''s fractal method is mathematically and visually very attractive but anatomically and developmentally misleading, and thus has limited, if any, biological significance. The same is true for the fractal demonstration of the external features of cauliflower curds. Actual fern leaves and cauliflower curds have a very small number of anatomically variable and non-iterating bifurcations, which superficially look self-similar, but do not allow for scaling down of their structure as real fractals do. Moreover, fern leaves and cauliflower curds develop from the inside out through a process totally different from fractal drawing procedures. The above cases demonstrate a general problem of using mathematical tools to investigate or illustrate biological phenomena in an irrelevant manner. A realistic set of mathematical equations to describe fern leaf or cauliflower curd development is needed.     

花椰菜自交系主要形态性状的主成分分析和聚类分析

通过对54个花椰菜自交系材料进行主成分分析和聚类分析研究,以期为花椰菜育种中亲本选配提供帮助。结果表明:在主成分分析中,选取方差累积贡献率为70.024%的前6个主成分来评价花椰菜自交系资源;现球期、采收期、叶长、叶宽、株高、花球纵径、花球横径、球重、球形、球紧实度、叶色、蜡粉、内叶数、始花期和株幅是花椰菜亲本选择的主要形态指标。进一步通过系统聚类,将54个花椰菜自交系分为3类:第Ⅰ类表现为早熟、株幅小、叶片狭窄、蜡粉较少、球重和紧实度中等;第Ⅱ类表现为中熟、株幅中等、叶片灰绿、蜡粉较厚和花球半圆紧实且重;第Ⅲ类表现为晚熟、株幅大、株形高、叶片宽阔、蜡粉中等和花球扁圆。3个类群自交系性状之间的差异较为明显,有利于杂交育种亲本材料的选择。     

Rapid in vitro propagation of cauliflower

A rapid single step method for complete plantlet regeneration in cauliflower is described. Curd explants cultured on Murashige and Skoog (MS) medium supplemented with 1 mg⁻¹ indoleacetic acid (IAA) developed complete plantlets in 25 days. Regeneration potential of curd explants was drastically reduced with increasing storage of cauliflower curds at room temperature beyond 8 days of harvesting. Light intensity of 3000 lux supplied by white fluorescent tubes was optimum to evoke the best response. It was possible to field transfer the hardened plantlets within 35 days of culture initiation.     

The pattern of frost-hardening of leaves of winter cauliflower (Brassica oleracea var. botrytis cv. Clause 30)

The suitability of an electrical conductivity assay of leaf material for determining frost hardiness in winter cauliflower was established. The assay was used to monitor the changes in hardiness of field-grown plants during two seasons at two sites. Levels of frost hardiness were related to mean air temperature over the 7-day period prior to sampling (r = 0.6008, P< 0.001). There was no clear disjunction of any temperature to indicate a threshold temperature of hardening. Dehardening occurred in spring and during mild spells in winter. In the mild regions where this crop is grown commercially it is likely that plants are not fully hardened for much of the winter. This may facilitate curd growth but may put the crop at risk from frost damage.     

Tissue specific expression of β-glucuronidase gene driven by heterologous promoters in transgenic cauliflower plants

In this paper we compare five heterologous promoters fused to β-glucuronidase gene in their influence on localization of GUS activity in cauliflower (Brassica oleracea var. botrytis) tissues: roots, leaves, petioles and curds. A constitutive promoter CaMV 35S and four tissue specific promoters were used: extAP from rape, PsMTAP from pea, RBCS3CP from tomato and SRS1P from soybean, and introduced into cauliflower seedling explants using Agrobacterium rhizogenes mediated transformation. Quantitative and histochemical GUS assays confirmed tissue specific gus expression. It was found that extAP promoter was the most active in petioles but also caused a significant gus expression in curds. GUS activity was hardly observed in curd and restricted only to its epidermis when PsMTAP promoter drove the gene. RBCS3CP and SRS1P promoters controlled similar expression of the gus gene throughout the plant except for curd where RBCS3CP was almost inactive.     

Survey of aliphatic glucosinolates in Sicilian wild and cultivated Brassicaceae

In the frame of the activities carried out to exploit Sicilian local cultivars of brassicas, we focused our attention on some of the potential health compounds of various local cruciferous crops. These compounds are of interest to improve the quality of the produce with the aim to develop new cultivars capable of providing functional foods able to prevent disease. In this context, we surveyed for the presence of specific glucosinolates in local cultivars of broccoli, cauliflower, kale, and in some wild species widespread in Sicily, using as control various commercial cultivars. Glucosinolate composition varied extensively among species and crops of the same species, such as cauliflower, broccoli and kale. Cultivar variation for glucosinolate profile was also observed for some crops. For example, Sicilian cultivars of cauliflower possessing colored curds displayed a high content of glucosinolates, glucoraphanin in particular, compared to white curd commercial cultivars. Also some wild species had a high content of other glucosinolates.     

松花菜种质资源评价及根肿病、黑斑病兼抗材料筛选

松花菜是目前我国花椰菜消费的主要类型。根肿病和黑斑病是直接影响松花菜产量及品质的重要病害。选育商品性好、高抗多抗品种是松花菜的主要育种目标之一。本研究首次建立了松花菜种质资源花球性状评价体系,从花球紧实度、球形、球面光滑度、球面颜色、球面蕾粒大小、二级侧枝长度、花梗颜色、球面长毛情况8个方面对66份松花菜自交系进行评价,并对不同性状赋值以便统计、比较。利用上述体系共筛选出11份花球性状优良的材料。采用苗期人工接种技术分别对松花菜根肿病和黑斑病抗性进行鉴定评价,结果显示无免疫根肿病材料,有2份高抗材料,9份抗病,16份中抗;无免疫和高抗黑斑病材料,有4份抗病材料,10份中抗。另外,兼抗两种病害的材料较少,其中GY-40对两种病害均表现抗病,GY-21对根肿病表现抗病,对黑斑病表现中抗,GY-39对两种病害均表现中抗。值得一提的是,GY-40性状优良且同时对根肿病和黑斑病具有较高抗性,是选育商品性好、抗病性强松花菜品种的理想亲本。本研究结果为评价松花菜种质资源花球相关性状提供了参考,对于规范资源的收集、整理和保存具有重要意义,同时为开展抗根肿病和黑斑病松花菜品种选育提供了优异材料。     

Osmotic pretreatment promotes axillary shooting from cauliflower curd pieces by acting through internal cytokinin level modifications

In vitro propagation of cauliflower has generally been achieved through axillary shoot proliferation of curd explants on Murashige and Skoog (MS) medium supplemented with an auxin and a cytokinin. Recently, it has been shown (Vandemoortele 1999) that a soaking in sucrose (-2 MPa for 24 h) of cauliflower curd explants, before culture without any growth regulator, also induced axillary branching. The later procedure avoids the phenomenon of hyperhydricity in the shoots formed. Axillary shooting obtained by the two methods appears to be mediated by modifications of internal cytokinin levels. The osmotic pretreatment did not influence auxin levels, but induced a zeatin and a zeatin riboside levels increase. Curd explants cultured with the usual procedure (on MS medium supplemented with 5 μmol/L BA and 0.5 μmol/L NAA) showed a zeatin and zeatin riboside levels increase of the same magnitude and a higher one for isopentenyl adenine and isopentenyl adenosine. The modification of the cytokinin status in the curd explants subjected to a short osmotic pretreatment thus should be less favourable for hyperhydricity.     

芸苔属植物CAL基因的结构特征与花球的形态遗传

Cauliflower curd is composed structurally of a number of shortened shoots on which there are tremendous amount of naked apical meristems. The authors isolated four pure lines of different curd types from cauliflower (Brassica oleracea L. var. botrytis) accessions: smooth curd (curd-s), haired curd (curd-h), crystal curd (curd-c) and thorned curd (curd-t). BobCAL genes was cloned separately from each pure line by PCR amplification and a termination mutation from AAG to TAG was found in the fifth exon of all four sequences, whereas DNA sequences of 638 bp upstream of the stop codons were identical, demonstrating that BobCAL is not the sole regulator of flower buds and cauline on curd. After crosses of cauliflower with cabbage (B.oleracea var. capitata) or broccoli (B.oleracea var. italica), the resultant F1 plants failed to form curd and had the diversity of inflorescence which implicates the relatedness of CAL to other regulators. One homologous gene of CAL, BcpCAL was isolated from Chinese cabbage (B.campestris L. ssp. pekinensis) and it was found not to have the termination mutation in the fifth exon, and thus the structure of BcpCAL gene was analyzed. The results offer molecular and genetic evidence for the study of biological function of CAL and morphological genetics of curd.     

外源BoCAL基因对花椰菜花球形态发生的调节及其遗传

花椰菜和结球甘蓝是芸薹属甘蓝种的两个变种,前者的BobCAL基因发生提前终止突变而失去了原有的功能,而后者的BoCAL基因具有完整的编码区。在农杆菌的介导下,我们获得了BoCAL转基因花椰菜。T_2代的遗传研究表明,外源BoCAL基因转入后花椰菜转基因植株都没有形成花球,而是只形成松散的由花蕾组成的绿色花序。这一结果说明,花椰菜BobCAL被甘蓝BoCAL互补了,转基因花椰菜因此失去了形成花球的能力。这些转基因植株自交到T_3代时花序的形态特征与T_2代一致,为松散的绿色花序,但是花序出现的时间与T_1代相比提早了15天。将转基因花椰菜与野生型花椰菜杂交,结果发现杂交后代的植株形成夹杂有花蕾的花球,且花序出现的时间大大推迟,在播种后135天后才形成花球。     

外源BoCAL基因对花椰菜花球形态发生的调节及其遗传

花椰菜和结球甘蓝是芸薹属甘蓝种的两个变种,前者的BoCAL基因发生提前终止突变而失去了原有的功能,而后者的BoCAL基因具有完整的编码区。在农杆菌的介导下,我们获得了BoCAL转基因花椰菜。T2代的遗传研究表明,外源BoCAL基因转入后花椰菜转基因植株都没有形成花球,而是只形成松散的由花蕾组成的绿色花序。这一结果说明,花椰菜BobCAL被甘蓝BoCAL互补了,转基因花椰菜因此失去了形成花球的能力。这些转基因植株自交到T3代时花序的形态特征与T2代一致,为松散的绿色花序,但是花序出现的时间与T1代相比提早了15天。将转基因花椰菜与野生型花椰菜杂交,结果发现杂交后代的植株形成夹杂有花蕾的花球,且花序出现的时间大大推迟,在播种后135天后才形成花球。     

Molecular characters and morphological genetics of CAL gene in Chinese cabbage

BepCAL,the homologous gene of CAL,was isolated from Chinese cabbage.Unlike BobCAL of cauliflower,BcpCAL did not hold the terninating mutation in the fifth exon.After crosses of cauliflower with Chinese cabbage,the resultant hybrids failed to form curd,which implicates the genetic complement of BcpCAL to the mutated BobCAL in the function of curd formation.One of CAL gene isolated from the hybrid apparently comes from the female parent(Chinese cabbage) even though there are a few of the bases substituted and deleted.The result offers the molecular and genetic evidences for the study of biological function of CAL in morphological genetics of curd.     

Preparation of a high-immunoglobulin product from bovine colostrum

An effective colostrum management programme is the most important factor in determining the health and survival of the neonatal calf. Commercially available colostrum replacers (CR) and colostrum supplements (CS) are an alternative to colostrum on farms that do not have an adequate, high-quality colostrum supply, or those farms that want to prevent transmission of disease from cow to calf. The present study aimed to obtain a high immunoglobulin (Ig), dried bovine colostrum product that could be used as a CR or CS for dairy calves. Dried whey was made from 6 batches of colostrum and an additional 6 batches were used to produce dried whey and curds. Dried whey had higher IgG concentration (P<0.05) and lactose (P<0.05), and less fat (P<0.05) compared to curds or the original colostrum. There was a strong linear relationship between initial colostrum IgG concentration and whey (R² = 0.86) with approximately 0.45 of the initial colostral IgG residing in curd. The high IgG and the composition of colostrum whey powder suggests it could be an effective CS product for use with dairy calves. The high fat and IgG content of the curd by-product indicate that it might be a potential weaning supplement in piglets or even a product for human consumption.     

Relationship between lactose utilization of lactic acid bacteria and browning of cheese during storage

ABSTRACT

To produce processed cheese turning hardly brown during transportation and storage at room temperature, natural cheese showing less discoloration should be used as a raw material. The purpose of this study was to clarify the relationship between the lactose utilization of lactic acid bacteria and the browning of cheese during storage. Three type-cultures (Lactobacillus plantarum and Streptococcus thermophilus) and five isolates from Japanese pickles (Lactobacillus spp.) were used. Cheese curds inoculated with these bacteria were prepared and stored. The L. plantarum-inoculated curds showed smaller ΔE-values after storage, an indicator for the browning, compared to the others. Accumulation of galactose was observed in the curd to which S. thermophilus was inoculated. The sample showed larger ΔE-value after storage. These results showed the lactose utilization of bacteria affected galactose concentration in cheese and its browning during storage. L. plantarum might be a good starter for preparing cheese turning hardly brown.     

MORPHOLOGY OF THE CURD OF CAULIFLOWER

Sadik , Sidki . (U. California, Davis.) Morphology of the curd of cauliflower. Amer. Jour. Bot. 49(3): 290–297. Illus. 1962.—The development of the curd and inflorescence of cauliflower, Brassica oleracea Linn., var. botrytis D.C., is described. The cultivars ‘Snowball M’ and ‘February-Early-March’ were studied. The curd has a nonfasciated and monopodial type of branching. Curd initiation of ‘Snowball M’ is not dependent on vernalization, but the curd of ‘February-Early-March’ and the floral primordia of both cultivars are initiated only after vernalization. Associated with flowering is the disruption of the curd by the elongation of some of the inflorescence branches. The initiation of leaves, branches, and floral primordia follows a 5 + 8 phyllotaxy throughout all stages of development. This system of phyllotaxy changes at the time of initiation of floral parts.     

Thermal acclimation in Arabidopsis lyrata: genotypic costs and transcriptional changes

Frost and heat events can be challenging for sessile organisms that cannot escape thermal extremes. However, adverse effects of thermal stress on fitness may be reduced by pre‐exposure to cold or heat, a process known as acclimation. To understand the ecological and evolutionary implications of acclimation, we investigated (1) the reduction in performance due to stress pre‐exposure, (2) the magnitude of increased leaf resistance to subsequent stress, (3) the costs of acclimation and (4) the genes differing in expression due to stress pre‐exposure. Plants of Arabidopsis lyrata were raised under three treatments of pre‐exposure: bouts of frost, bouts of heat or constant temperature. Resistance of leaves to subsequent frost and heat stress was then measured by electrolyte leakage. RNA‐seq analysis was performed to examine the genes differentially expressed between stress‐pre‐exposed and control plants. Pre‐exposure to stress during growth decreased plant size and increased leaf resistance to subsequent stress independent of whether pre‐exposure was to frost or heat. But the highest increase in leaf resistance to frost was found after pre‐exposure to frost (as a trend) and in leaf resistance to heat after pre‐exposure to heat. No evidence for costs of acclimation was detected. RNA‐sequencing suggested that acclimation by frost and heat pre‐exposure was caused by distinct mechanisms: modification of the chloroplast membrane and modification of the cell wall and membrane, respectively. Our results suggest that thermal resistance is a labile complex of traits, strongly affected by the previously experienced stress environment, with undetermined costs.     

The distribution of BoCAL-a alleles in Brassica oleracea is consistent with a genetic model for curd development and domestication of the cauliflower

The characteristic curd of cauliflower (Brassica oleracea var. botrytis L.) consists of proliferating, arrested inflorescence and floral meristems. However, the origins and events leading to the domestication of this important crop trait remain unclear. A similar phenotype observed in the ap1-1/cal-1 mutant of Arabidopsis thaliana led to speculation that the orthologous genes from B. oleracea may be responsible for this characteristic trait. We have carried out a detailed molecular and genetic study, which allows us to present a genetic model based on segregation of recessive alleles at specific, mapped loci of the candidate genes BoCAL and BoAP1. This accounts for differences in stage of arrest between cauliflower and Calabrese broccoli (B. oleracea var. italica Plenck), and predicts the intermediate stages of arrest similar to those observed in Sicilian Purple types. Association of alleles of BoCAL-a with curding phenotypes of B. oleracea is also demonstrated through a survey of crop accessions. Strong correlations exist between specific alleles of BoCAL-a and discrete inflorescence morphologies. These complementary lines of evidence suggest that the cauliflower curd arose in southern Italy from a heading Calabrese broccoli via an intermediate Sicilian crop type. PCR-based assays for the two key loci contributing to curd development are suitable for adoption in marker-assisted selection.