Auxin-induced Expansion Growth in Disks of Chicory Root (Cichorium intybus)

Expansion growth in response to auxin in chicory root slices is greater than that reported for any other fleshy tissue. Responsiveness depends on time of harvest and duration of root storage.     

The Influence of Nitrogen Supply on the Uptake and Remobilization of Stored N for the Seasonal Growth of Apple Trees

M26 apple rootstocks were grown in sand culture and suppliedwith three rates of nitrogen (N) with the irrigation: none,0·8 mol N m^–2 or 8·0 mol N m^–2. Allthe N supplied to the trees was labelled with ¹⁵N at 5·0atom percent enrichment. The effect of N supply on tree growth,N uptake and the remobilization of N from stems for the annualgrowth of the trees was measured. Increasing the N supply increasedleaf growth, but had no effect upon root mass and so alteredthe root/leaf dry matter ratio Plants receiving no fertilizer N had to rely entirely upon storedreserves of N for their seasonal growth. Initially this N wasused for leaf growth, which stopped after a few weeks. Thereafterthe N-deficient plants retranslocated some of the N from theirleaves to support root growth. Increasing the N supply had littleeffect upon the amount of N remobilized for growth, althoughwell-fertilized plants accumulated N in their leaves and didnot retranslocate any to support root growth. The partitioningof N between roots and shoots was, therefore, altered by increasingthe N supply. Amino acid analysis of stems showed that the majorforms of N remobilized during growth were protein rich in asparagineand arginine The results show the importance of internal N cycling for thegrowth of young apple trees, and are discussed in relation toother studies of N cycling in deciduous trees Malus domestica Borkh., nitrogen, remobilization, growth, partitioning, storage     

The Remobilization of Nitrogen Related to Leaf Growth and Senescence in Rice Plants (Oryza sativa L.)

Rice plants (Oryzae sativa L.) grown in a nutrient solutionwere fed with (¹⁵NH₄)₂SO₄ during the 5 days of their young panicleformation. At the end of that time in the youngest leaf blade, which hadstarted to emerge during the labelling, absorbed-nitrogen accountedfor 37% of the increased nitrogen of the tissue; in the nextdeveloping leaf blade it accounted for 55%. Thus, remobilized-nitrogenoriginating from older patrs of the plant made up 63 and 45%,respectively, of their total nitrogen. The important contributionof the remobilized-nitrogen to the development of a leaf isevident. The remobilization of nitrogen in the 12th leaf blade on themain stem was examined in detail after labelling during itsdeveloping stage. The ¹⁵N level started to decrease soon afterthe end of the labelling period and continued to decrease untilfull senescence, although the total nitrogen in the same leafincreased until just after its complete expansion, suggestingthat even a young leaf plays a role as a supplier of remobilized-nitrogen. During the rapid decrease in the total nitrogen after its peakat full expansion of the leaf, the actual proportion of labelledabsorbed nitrogen remained nearly the same, indicating thatinflux of new nitrogen into a senescing leaf is very limited. (Received March 13, 1981; Accepted July 13, 1981)     

Nitrate (15NO3) limitation affects nitrogen partitioning between metabolic and storage sinks and nitrogen reserve accumulation in chicory (Cichorium intybus L.)

In chicory, we examined how NO₃ ⁻ supply affected NO₃ ⁻ uptake, N partitioning between shoot and root and N accumulation in the tuberized root throughout the vegetative period. Plants were grown at two NO₃ ⁻ concentrations: 0.6 and 3 mM. We used ¹⁵N-labelling/chase experiments for the quantification of N fluxes between shoot and root and for determining whether N stored in the tuberized root originates from N remobilized from the shoot or from recently absorbed NO₃ ⁻. The rate of ¹⁵NO₃ ⁻ uptake was decreased by low NO₃ ⁻ availability at all stages of growth. In young plants (10–55 days after sowing; DAS), in both NO₃ ⁻ treatments the leaves were the strongest sink for ¹⁵N. In mature (tuberizing) plants, (55–115 DAS), the rate of ¹⁵NO₃ ⁻ uptake increased as well as the amount of exogenous N allocated to the root. In N-limited plants, N allocation to the tuberized root relied essentially on recent N absorption, while in N-replete plants, N remobilized from the shoot contributed more to N-reserve accumulation in the root. In senescing plants (115–170 DAS) the rate of ¹⁵NO₃ ⁻ uptake decreased mainly in N-replete plants whereas it remained almost unchanged in N-limited plants. In both NO₃ ⁻ treatments the tuberized root was the strongest sink for recently absorbed N. Remobilization of previously absorbed N from shoot to tuberized root increased greatly in N-limited plants, whereas it increased slightly in N-replete plants. As a consequence, accumulation of the N-storage compounds vegetative storage protein (VSP) and arginine was delayed until later in the vegetative period in N-limited plants. Our results show that although the dynamics of N storage was affected by NO₃ ⁻ supply, the final content of total N, VSP and arginine in roots was almost the same in N-limited and N-replete plants. This indicates that chicory is able to build up a store of available N-reserves, even when plants are grown on low N. We also suggest that in tuberized roots there is a maximal capacity for N accumulation, which was reached earlier (soon after 100 DAS) in N-replete plants. This hypothesis is supported by the fact that in N-replete plants despite NO₃ ⁻ availability, N accumulation ceased and significant amounts of N were lost due to N efflux. Received: 14 October 1996 / Accepted: 4 February 1997     

Influence of Polyamines on Growth of Hairy Root Cultures of Witloof Chicory (Cichorium intybus L. cv. Lucknow Local) and Formation of Coumarins

The effect of polyamines (putrescine, spermidine, and spermine) was examined for growth and production of two coumarins, esculetin and esculin, in the hairy roots of chicory (Cichorium intybus L. cv. Lucknow local). Of the polyamines administered, 1.5 mm putrescine alone resulted in a 2.3-fold higher increase in the growth of hairy roots as well as in the production of esculetin and esculin, which was 3.37 times more than that of the control on day 21. The endogenous level of conjugated putrescine was more than fivefold that of free putrescine levels in untreated samples. The production of esculetin and esculin in hairy root cultures strictly correlated with growth in all of the treatments. Putrescine at 1.5 mm resulted in a greater length of primary root (18.29 ± 1.37 cm) compared with the control (10.96 ± 0.82 cm) and more secondary and tertiary roots. This study also provides insight into the morphogenetic changes that occur in roots in response to the external supply of polyamines. Received July 20, 1998; accepted January 19, 1999     

Putrescine Influences Growth and Production of Coumarins in Hairy Root Cultures of Witloof Chicory (Cichorium intybus L. cv. Lucknow Local)

The effect of putrescine (Put) on the growth and production of two coumarins, esculin and esculetin, in hairy roots of chicory (Cichorium intybus L. cv. Lucknow local) was examined. To study the role of Put on growth and production of coumarins, polyamine inhibitors, namely α-dl-difluromethylornithine and α-dl-difluromethylarginine were used at 1 mM concentration. Put treatment at 1.5 mM produced a 1.9-fold increase in the growth of hairy roots, as well as the production of esculin and esculetin. The treatments with polyamine (PA) inhibitors resulted in much lower growth and production of coumarins compared with both 1.5-mM Put treatment and the control. Both free and conjugated PAs were studied over the whole culture period, and conjugates of all three PAs, namely Put, spermidine, and spermine, were higher than free PAs throughout the culture period. The treatments with PA inhibitors showed lower levels of endogenous PAs compared with Put-treated samples. The treatment with 1.5 mM Put showed maximum accumulation of endogenous conjugated Put (2,098 ± 157 nmoles gm⁻¹ fresh weight). The production of esculin and esculetin was strictly correlated with growth in all treatments. Put at 1.5 mM resulted in greater length of primary root (18.3 ± 1.4 cm) as compared with the control (11 ± 0.9 cm) and larger numbers of secondary and tertiary roots. Received July 14, 1999; accepted October 5, 1999     

Sodium-Stimulated NO(3) Uptake in Amaranthus tricolor L. Plants

Nitrate uptake of Na⁺ -deficient Amaranthus tricolor L. cv Tricolor seedlings from complete culture solution was stimulated by about 210% within 5 hours by application of 0.5 millimolar NaCl. From a Na⁺ -preloading experiment, intracellular Na⁺ was shown to be responsible for the stimulation of NO₃⁻ uptake. The results suggest a possible role of Na⁺ in NO₃⁻ uptake in C₄ plants.     

Differences in Nitrogen Metabolism During Growth of Plants from Aged Potato (Solanum tuberosum L.) Meristems

The effect of advanced meristem age on growth and accumulationof plant nitrogen (N) in potato (Solanum tuberosum L.) was studied.Etiolated plantlets, excised from sprouted, single-eye-containingcores from 7 and 19-month-old seed-tubers, were transplantedinto aerated nutrient culture. Rates of shoot and root dry matterand shoot soluble-N (which included nitrate-N) accumulationwere similar for plants from both meristem ages over a 30 dinterval of log-linear growth. The rate at which nitrate-N accumulatedwas consistently 17 per cent higher in shoots from 19-month-oldcompared to those from 7-month-old meristems. However, accumulationof free amino-N and soluble protein-N were 21 and 15 per centlower, respectively in shoots from 19-month-old meristems. Abuild-up of shoot nitrate, along with lower rates of accumulationof amino-N and soluble protein-N, suggests a lower capacityfor nitrate reduction during early growth of plants from oldermeristems. Furthermore, these effects can be attributed to age-inducedchanges in the meristem or bud tissue as the plants were separatedfrom the tuber tissue initially in the study. Long-term ageingof seed-potatoes apparently affects changes within meristemsthat translate into a lower capacity to accumulate reduced formsof nitrogen during early plant growth. Potatoes (Solanum tuberosum L.), meristem age, nitrogen metabolism, plant growth potential     

The temporal development in a hybridizing population of wild and cultivated chicory (Cichorium intybus L.)

Hybridization and its possible impacts is a subject of increased attention in connection with the risk of unintended gene flow from cultivated (including genetically modified) plants to wild relatives. Whether such gene flow by hybridization is likely to take place depends among other things on the persistence of the hybrids in a natural environment over time. To evaluate this, we studied an experimental hybridizing population of wild and cultivated chicories (Cichorium intybus) relative to a previous study on the same population 2 years earlier. We compared the genetic composition, morphology and fitness traits of plants from 2004 to the plants in the same plot in 2002. The majority of the plants in 2004 was more morphologically and genetically intermediate than in 2002. This indicates that no selection towards being wild-like or cultivar-like was present over the period of 2 years. Furthermore, no distinct fitness differences existed between the plants of 2004, probably due to most of the plants being intermediate. No hybridization barriers appeared to be present between wild and cultivated chicories beyond the F1 generation, since F2 hybrids and backcrosses were in abundance; in fact, hybrids of probably fourth or fifth generation were present. In conclusion, all results indicate that no barriers exist to the temporal persistence of chicory hybrids in a natural environment.     

Development of SSR markers and construction of a consensus genetic map for chicory (Cichorium intybus L.)

A consensus genetic map for chicory (2n = 2x = 18) was obtained after the integration of molecular marker data of two industrial chicory progenies (K28K59, Rubis118) and one witloof chicory progeny (BR). As a limited number of co-dominant markers was available at the beginning of this work, three different microsatellite-enriched libraries were produced from genomic DNA, resulting in 420, 719 and 1,251 sequences, respectively. The level of informative Simple Sequence Repeat (SSR) sequences from the three libraries ranged from 28 to 40%, thus defining a set of 730 SSR markers available for polymorphism screening. A subset of 81 Sequence-Tagged Sites (STS) developed from EST, cDNA, genes, and non-coding sequences was screened through Single Strand Conformational Polymorphism (SSCP) analysis, leading to 46 polymorphic loci integrated in the genetic maps. Markers were grouped and ordered on 9 homologous Linkage Groups (LG) for each of the three maps: 274 markers in K28K59, 282 markers in Rubis118, 178 markers in BR. Co-linear regions between maps were identified through 193 ‘bridge’ markers that allowed the integration of the 9 homologous LG in a consensus map containing 472 markers and covering 878 cM. Comparison across maps revealed the presence of 4 conserved regions with significant distorted markers, also defined as Segregation Distortion Regions (SDR), affected by gametic or zygotic selection factors. Marker distribution was not always uniform; 6 LG possessed homologous clustered regions in all maps. The consensus map could be the starting point for the identification and the cloning of major genes and QTL in fundamental and applied genetic areas in chicory.     

海水灌溉欧洲菊苣盐肥耦合效应

2008年在江苏北部沿海滩涂进行田间试验研究了不同浓度海水灌溉下欧洲菊苣(Cicherium intybus L.)的盐肥耦合效应。结果表明:1)20%海水灌溉下欧洲菊苣肉质根和地上部分生物产量与淡水处理相比没有显著差异,而40%海水灌溉下产量均显著下降;N3(氮用量90kg.hm-2)水平与N1(氮用量0kg.hm-2)水平相比,欧洲菊苣肉质根产量与地上部分生物产量可以显著提高;同样,P3(P2O5用量45kg.hm-2)水平与P1(P2O5用量0kg.hm-2)水平相比,欧洲菊苣产量亦显著提高。2)各浓度海水灌溉下,随着施氮、磷量的增加菊苣主茎普遍增长和增粗。3)经过海水与氮肥及磷肥的交互作用对总产量影响的分析,可以看出W1N3(淡水,氮用量90kg.hm-2)和W1P3(淡水,P2O5用量45kg.hm-2)是优化组合。4)经过海水与氮肥及磷肥的交互作用对籽粒产量影响的分析,可以看出W2N3(20%海水,氮用量90kgN.hm-2)和W1P2(淡水,P2O5用量22.5kg.hm-2)是优化的组合。处理因子分析表明:海水、氮肥、磷肥对欧洲菊苣产量具有显著效应,以海水影响最大;总产量的优化组合为W1N3P...     

The Nitrogen Use Efficiency of C(3) and C(4) Plants: I. Leaf Nitrogen, Growth, and Biomass Partitioning in Chenopodium album (L.) and Amaranthus retroflexus (L.)

The effect of applied nitrogen (N) on the growth, leaf expansion rate, biomass partitioning and leaf N levels of Chenopodium album (C₃) and Amaranthus retroflexus (C₄) were investigated. At a given applied N level, C. album had 50% greater leaf N per unit area (N_a) than A. retroflexus. Nitrate accumulated at lower N_a in A. retroflexus than C. album. A. retroflexus was more productive than C. album at high N, but C. album was more productive at low N. At high applied N, nitrogen use efficiency (NUE), expressed either as net assimilation rate (NAR) per unit N or relative growth rate per unit N, was greater in A. retroflexus than C. album. However, at low applied N, C. album had a greater NUE on both an NAR and growth basis than A. retroflexus. The leaf area partitioning coefficient was similar in the species at high N, but was greater in A. retroflexus than C. album at low N. At low N, greater leaf area partitioning apparently lowered leaf N in A. retroflexus to levels at which necrosis occurred. In C. album by contrast, leaf area partitioning declined to a greater degree with declining N than it did in A. retroflexus, so that leaf N did not decline as much. Consequently, low N C. album plants did not lose leaf area to necrosis and had a greater NAR and NUE at low applied N than A. retroflexus.     

The bacterial microflora of witloof chicory (Cichorium intybus L. var.foliosum Hegi) leaves

The bacterial flora on the heads of four different witloof chicory varieties was examined. The 590 isolates were characterized by their SDS-PAGE protein profiles; they revealed 149 different protein fingerprint types. The fluorescentPseudomonas fingerprint type CH001 was abundantly found on all heads examined. Fourteen other fingerprint types occurred in high densities more than twice. Among these, the following were identified: fluorescentPseudomonas, nonfluorescentPseudomonas sp.,Erwinia herbicola, Erwinia sp., andFlavobacterium sp. The majority of the fingerprint types (90%) was found only once. It was also our objective to isolate bacteria applicable in the biological control of chicory phytopathogens. Isolates of all fingerprint types were tested for in vitro antagonistic activity and for possible deleterious effect on plant growth. FluorescentPseudomonas andSerratia liquefaciens isolates were antagonistic against fungi. Among the 161 fluorescentPseudomonas strains, five were able to produce disease symptoms on chicory leaves upon inoculation. Comparison of the results of this study with those obtained in two previous analyses revealed that the leaf microflora showed some similarities with the bacterial flora of chicory roots. The chicory seed microflora differed from that of both leaves and roots.     

Exogenous NO(3) Influx and Endogenous NO(3) Efflux by Two Maize (Zea mays L.) Inbreds during Nitrogen Deprivation

The influence of nitrogen stress on net nitrate uptake resulting from concomitant ¹⁵NO₃⁻ influx and ¹⁴NO₃⁻ efflux was examined in two 12-day-old inbred lines of maize. Plants grown on ¹⁴NO₃⁻ were deprived of nitrogen for up to 72 hours prior to the 12th day and then exposed for 0.5 hour to 0.15 millimolar nitrate containing 98.7 atom% ¹⁵N. The nitrate concentration of the roots declined from approximately 100 to 5 micromolar per gram fresh weight during deprivation, and ¹⁴NO₃⁻ efflux was linearly related to root nitrate concentration. Influx of ¹⁵NO₃⁻ was suppressed in nitrogen-replete plants and increased with nitrogen deprivation up to 24 hours, indicating a dissipation of factors suppressing influx. Longer periods of nitrogen-deprivation resulted in a decline in ¹⁵NO₃⁻ influx from its maximal rate. The two inbreds differed significantly in the onset and extent of this decline, although their patterns during initial release from influx suppression were similar. Except for plants of high endogenous nitrogen status, net nitrate uptake was largely attributable to influx, and genetic variation in the regulation of this process is implied.     

Growth, fructan yield, and quality of chicory (Cichorium intybus L.) as related to photosynthetic capacity, harvest time, and water regime

Fructans are polymers that are widely used in several industrial applications. In the last few years they have received increasing interest because of their positive effects on health. At present, fructans are mostly supplied by chicory, which is only grown and processed in The Netherlands, France, and Belgium. It would therefore be an attractive concept to expand its cultivation to the southern European countries, although water shortage and high temperatures may hinder its growth and yield. So far, few experiments have been carried out on the effects of water, so the present research was focused on the course of growth and fructan quality in rainfed (W(0)) and well-watered (W(1)) conditions. The positive effects of water restoration mostly concerned the above-ground dry weight (ADW), whereas the root dry weight (RDW) was less influenced. No significant differences on RDW were found in 1999, whereas it was 14% higher (P <0.01) in W(1) in 2000. The effect of water was very clear on assimilate allocation: the overall priority at the whole plant scale seemed to be root structures, then storage reserves, and finally ADW. Therefore, the fructan content was higher in W(0), and insignificant differences between W(0) and W(1) were found on fructan yield at the final harvests. The only significant effect of the water regime on fructans was to speed up their storage. The leaf photosynthetic capacity (A) was poorly affected by water availability, whereas it appeared consistently modulated by leaf temperature and leaf nitrogen content. Stomatal conductance appeared to be mostly affected by the soil water content and it was mostly related to A up to about 300 mmol m(-2) s(-1). The fructan chain length (DP) was not affected by water regime. Besides, DP classes showed a normal statistical distribution; skewness and kurtosis significantly changed only when the harvest was very late. Equally, a very late harvest time significantly lowered DP.     

Agrobacterium mediated transfer of a mutant Arabidopsis acetolactate synthase gene confers resistance to chlorsulfuron in chicory (Cichorium intybus L.)

Summary Leaf discs of C. intybus were inoculated with an Agrobacterium tumefaciens strain harboring a neomycin phosphotransferase (neo) gene for kanamycin resistance and a mutant acetolactate synthase gene (csr1-1) from Arabidopsis thaliana conferring resistance to sulfonylurea herbicides. A regeneration medium was optimized which permitted an efficient shoot regeneration from leaf discs. Transgenic shoots were selected on rooting medium containing 100 mg/l kanamycin sulfate. Integration of the csr1-1 gene into genomic DNA of kanamycin resistant chicory plants was confirmed by Southern blot hybridizations. Analysis of the selfed progenies (S1 and S2) of two independent transformed clones showed that kanamycin and chlorsulfuron resistances were inherited as dominant Mendelian traits. The method described here for producing transformed plants will allow new opportunities for chicory breeding.