Lipid peroxidation inhibitory compounds from daylily (Hemerocallis fulva) leaves

Daylilies (Hemerocallis spp.) have been used as food and in traditional medicine for thousands of years in eastern Asia. The leaves of the plant are used in the treatment of inflammation and jaundice. In studies of the aqueous methanol extracts of fresh Hemerocallis fulva leaves, 1',2',3',4'-tetrahydro-5'-deoxy-pinnatanine (1), pinnatanine (2), roseoside (3), phlomuroside (4), lariciresinol (5), adenosine (6), quercetin 3-O-beta-D-glucoside (7), quercetin 3,7-O-beta-D-diglucopyranoside (8), quercetin 3-O-alpha-L-rhamnopyransol-(1-->6)-beta-D-glucopyranosol-7-O-beta-D-glucopyranoside (9), isorhamnetin-3-O-beta-D-6'-acetylglucopyranoside (10) and isorhamnetin-3-O-beta-D-6'-acetylgalactopyranoside (11) were isolated. All of these compounds were tested for their in vitro lipid peroxidation inhibitory activities. Compounds 3-5 and 7-11 were found to possess strong antioxidant properties, inhibiting lipid oxidation by 86.4, 72.7, 90.1, 79.7, 82.4, 89.3, 82.2, and 93.2%, respectively at 50 microg/mL. Compound 1 is novel and compounds 3-6 and 8-11 described here in are isolated for the first time from daylily leaves.     

Evaluation of genetic variation in the daylily (Hemerocallis spp.) using AFLP markers

The daylily (Hemerocallis spp.) is one of the most economically important ornamental plant species in commerce. Interestingly, it is also one of the most heavily bred crops during the past 60 years. Since the American Hemerocallis Society began acting as the official registry of daylily cultivars in 1947, more than 40 000 registrations have been processed. In order to determine the effects of intensive breeding on cultivar development, and to study relationships among different species, genetic variation in the daylily was estimated using AFLP markers. Nineteen primary genotypes (species and early cultivars) and 100 modern cultivars from different time periods were evaluated using 152 unambiguous bands (average 79% polymorphism rate) derived from three AFLP primer combinations. Overall, pairwise similarity estimates between entries ranged between 0.618 and 0.926 (average=0.800). When comparing cultivar groups from different time periods (1940–1998), genetic similarity was initially increased, compared to the primary diploid genotypes, remained constant from 1940 to 1980, and then steadily increased as breeding efforts intensified and hybridizers began focusing on a limited tetraploid germplasm pool derived by colchicine conversion. Among modern (1991–1998) daylily cultivars, genetic similarity has increased by approximately 10% compared to the primary genotypes. These data were also used to evaluate recent taxonomic classifications among daylily species which, with a few minor exceptions, were generally supported by the AFLP data. Received: 15 March 2000 / Accepted: 13 June 2000     

Isolation of polymorphic microsatellite loci in Hemerocallis fulva and Hemerocallis citrina (Hemerocallidaceae)

Twenty microsatellite loci were isolated from a hybrid of two daylilies, Hemerocallis fulva and Hemerocallis citrina. We characterized individuals from two H. fulva populations and two H. citrina populations in Japan and observed three to 20 alleles per locus in H. fulva and one to 19 alleles per locus in H. citrina. Mean observed heterozygosity within populations ranged from 0.35 to 0.85 in H. fulva and from 0 to 0.95 in H. citrina. In about a half of the loci, the observed heterozygosity did not deviate from Hardy–Weinberg equilibrium. These loci are proved useful in studying gene flow and qualitative trait loci mapping using the two species.     

Numerical Taxonomic Studies of Hemerocallis (Liliaceae) from China

Taxonomic studies of 11 taxa in Hemerocallis from China were conducted using cluster analysis and principal components analysis. The taxa were grouped into four clusters. The Cluster one includs H. citrina, H. lilioasphodelus, H. minor and H. multiflora ; the second cluster H. dumortieri and H. middendorfii ; the third cluster H. plicata, H. forresti and H. nana; and the fourth cluster di-and triploid of H. fulva. Relationships between the taxa within clusters as well as the subdivision of the genus are discussed.     

Antibodies to phase related proteins in juvenile and mature Prunus avium

In the search for biochemical and molecular markers of juvenility in trees proteins have been identified which are preferentially or differentially expressed in either the juvenile or the mature phases of Prunus avium cv. Stella. These fall into two classes: those which are phase-related and those which may be affected by root-shoot distance. N-terminal amino acid sequence data from some of these proteins were used to produce polyclonal antibodies to corresponding synthetic peptides in order to determine if they could be used as markers of phase state in woody plants. Western blot analysis was performed on proteins extracted from three sources; juvenile trees, mature trees and rooted cuttings from mature trees. The results showed that the antibodies recognised differentially-expressed proteins. In particular, one antibody to a juvenile specific protein cross-reacted with a polypeptide of approx. 28 kDa which was present in greater amounts in shoot tips of juvenile P. avium cv. Stella seedlings compared with rooted cuttings of mature plants placed in the same growth environment.     

Numerical Cytotaxonomic Studies of Hemerocallis (Liliaceae) from China

Comparative studies of karyotypes in Hemerocallis from China have been carried out using numerical techniques. Taxa studied are as follows: Hemerocallis citrina, H. dumortieri , H. esculenta , H. forrestii , di- and triploid H. fulva , H. lilioasphodelus , H. middendorffii, H. minor, H. multiflora and H. plicata. The results show that variation in speciation has taken place at chromosomal level, and that karyotype variations have largely paralleled the morphological ones. Taxonomic proposals are given to treat H. citrina and H. minor as subspecies of H. lilioasphodelus, and H. esculenta as a variety of H. dumortieri. The results are not in favour of considering H. middendorffii as a variety ofH. dumortieri, and H. multiflora closely related to H. plicata.     

大花萱草‘金娃娃’雌雄蕊发育进程及其与花蕾长度的相关性研究

采用石蜡切片法对大花萱草'金娃娃'(Hemerocallis hybridus cv.'Stella de oro')不同花蕾长度时雌雄蕊的形态及其发育时期进行观察,以探讨花营长度与雌雄蕊发育进程的相关性.结果显示:(1)'金娃娃'雄蕊发育正常,小孢子发生及雄配子体的发育过程与常见单子叶植物类似,成熟花粉属二胞型;雌蕊子房具多胚珠,但各胚珠中雌配子体发育进程不同步,出现大量无胚囊或胚囊内核发育紊乱、解体的现象而导致雌配子体发育不正常,大田结实率不到5%且种子干瘪不能发芽.(2)'金娃娃'花蕾长度与花粉发育时期具有相关性,为花蕾长度作为组织培养外植体取材外形标准提供丁植物胚胎学依据.     

Influence of auxins and darkness on in vitro rooting of micropropagated shoots from mature and juvenile Acacia mangium

The influence of total darkness versus a 16/8 photoperiod and of auxins added to the culture medium on the in vitro root formation capacity of Acacia mangium microshoots of juvenile and mature origin was examined. Rooting of the mature clone was significantly increased by exposing the microshoots to auxins (4 and 6 μM IAA or IBA) in darkness, while the promoting effect of darkness combined with 4 μM IAA was more time-restricted for the juvenile-origin microshoots. Overall, the latter rooted in greater proportions than those from the mature source. Maintaining the microshoots of both origins on auxin supplemented medium in darkness resulted in a greater number of adventitious roots formed than under the standard 16/8 lighting conditions. On the other hand, light stimulated root elongation. These results are discussed mainly from the viewpoint of auxin metabolism in relation to adventitious root formation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effects of population succession on demographic and genetic processes: predictions and tests in the daylily Hemerocallis thunbergii (Liliaceae)

Spatial genetic structure within plant populations is influenced by variation in demographic processes through space and time, including a population's successional status. To determine how demographic structure and fine-scale genetic structure (FSGS) change with stages in a population's successional history, we studied Hemerocallis thunbergii (Liliaceae), a nocturnal flowering and hawkmoth-pollinated herbaceous perennial with rapid population turnover dynamics. We examined nine populations assigned to three successive stages of population succession: expansion, maturation, and senescence. We developed stage-specific expectations for within-population demographic and genetic structure, and then for each population quantified the spatial aggregation of individuals and genotypes using spatial autocorrelation methods (nonaccumulative O-ring and kinship statistics, respectively), and at the landscape level measured inbreeding and genetic structure using Wright's F-statistics. Analyses using the O-ring statistic revealed significant aggregation of individuals at short spatial scales in expanding and senescing populations, in particular, which may reflect restricted seed dispersal around maternal individuals combined with relatively low local population densities at these stages. Significant FSGS was found for three of four expanding, no mature, and only one senescing population, a pattern generally consistent with expectations of successional processes. Although allozyme genetic diversity was high within populations (mean %P = 78.9 and H(E) = 0.281), landscape-level differentiation among sites was also high (F(ST) = 0.166) and all populations exhibited a significant deficit of heterozygotes relative to Hardy-Weinberg expectations (range F = 0.201-0.424, mean F(IS) = 0.321). Within populations, F was not correlated with the degree of FSGS, thus suggesting inbreeding due primarily to selfing as opposed to mating among close relatives in spatially structured populations. Our results demonstrate considerable variation in the spatial distribution of individuals and patterns and magnitude of FSGS in H. thunbergii populations across the landscape. This variation is generally consistent with succession-stage-specific differences in ecological processes operating within these populations.     

萱草花粉微管蛋白的体外聚合及电镜观察

微管(microtubule)作为细胞骨架的主要成分,在植物体内,微管除决定细胞的形状外,还参与很多重要的细胞功能。但有关微管蛋白生物化学的研究绝大多数来自动物脑组织材料,对植物微管蛋白的研究除培养细胞外所知甚少,我们纯化了毫克数量的萱草(Hemer-ocallis fulvaL.)花粉微管蛋白,利用紫杉醇作为促进剂,在Mg2 、GTP等存在下体外聚合成功,并观察了其电镜下的形态。     

Microarray analysis of vegetative phase change in maize

Vegetative phase change is the developmental transition from the juvenile phase to the adult phase in which a plant becomes competent for sexual reproduction. The gain of ability to flower is often accompanied by changes in patterns of differentiation in newly forming vegetative organs. In maize, juvenile leaves differ from adult leaves in morphology, anatomy and cell wall composition. Whereas the normal sequence of juvenile followed by adult is repeated with every sexual generation, this sequence can be altered in maize by the isolation and culture of the shoot apex from an adult phase plant: an 'adult' meristem so treated reverts to forming juvenile vegetative organs. To begin to unravel the as-yet poorly understood molecular mechanisms underlying phase change in maize, we compared gene expression in two juvenile sample types, leaf 4 and culture-derived leaves 3 or 4, with an adult sample type (leaf 9) using cDNA microarrays. All samples were leaf primordia at plastochron 6. A gene was scored as 'phase induced' if it was up- or downregulated in both juvenile sample types, compared with the adult sample type, with at least a twofold change in gene expression at a P-value of < or =0.005. Some 221 expressed sequence tags (ESTs) were upregulated in juveniles, and 28 ESTs were upregulated in adults. The largest class of juvenile-induced genes was comprised of those involved in photosynthesis, suggesting that maize plants are primed for energy production early in vegetative growth by the developmental induction of photosynthetic genes.     

In vitro rooting of micropropagated shoots from juvenile and mature Pinus pinaster explants: influence of activated charcoal

The ability for adventitious rooting of micropropagated shoots from juvenile and mature Pinus pinaster Ait. explants was assessed in vitro on a rooting expression medium. The different rooting traits observed, namely the rooting rate, the number and the length of the adventitious roots, and the root score, were greatly influenced by the age of the donor plant: 98% of juvenile explants rooted, while only 49% of mature explants did. Addition of activated charcoal in the rooting expression medium improved the overall rooting capacity of the mature explants to an average of 78%. Whatever the plant material, the number and the length of the adventitious roots, as well as the root score, fluctuated according to the sampling date.Abbreviations BA 6-benzyladenine - NAA naphthaleneacetic acid - REM rooting expression medium - RIM rooting induction medium     

Taxonomic Studies on the Nocturnal Flowering Group of Hemerocallis (Liliaceae) from China

The nocturnal-flowering group of Hemerocallis was treated as including three separate species, H．lilioasphodelus,H.citrina and H．minor in the Florae Reipublicae Popularis Sinicae Vol．14(1980)．However it is difficult to distinguish them from one another by a single feature,such as the flower number,length of perianth tube,diameter of tuberous roots,for they are strongly overlapping．In the present paper,numerical analysis was made of nine morphological characters and karyotype divergences which are of taxonomic significance as shown in the study of H． fulva and its two varieties (Xiong and Chen,1992),based on dry and living materials from China．In addition,geographical distribution pattern of the three taxa studied shows that they seem to be different geographical races or allopatric ecotypes in a topocline,since they inhabit a climate gradient from warm and moist to cold and drought condition．As a result,the present authors tend to consider it more reasonable to treat them as a single species,H．lilioasphodelus,with three subspecies,that is, H．lilioasphodelus ssp．lilioasphodelus,H．lilioasphodelus ssp． citrina (stat．nov) and H．lilioasphodelus ssp．minor(stat．nov．)     

Bimodal distribution of flowering time in a natural hybrid population of daylily (Hemerocallis fulva) and nightlily (Hemerocallis citrina)

Time of flower anthesis in a day is thought to evolve in response to the time of pollinator activities. We studied blooming and withering time in natural populations of daylily (Hemerocallis fulva), nightlily (Hemerocallis citrina) and their hybrids, and also in an artificially obtained array of the F1 hybrids. Blooming time of H. fulva varied from 4:30 to 7:30 and H. citrina varied from 16:30 to 20:30. In a natural hybrid population, blooming time and withering time showed discontinuous bimodal distribution in spite that morphological traits of flowers showed continuous unimodal variation. Most F1 hybrids showed diurnal flowering. These findings indicate that only a few genes have strong phenotypic effect on the determination of flowering time in Hemerocallis, and suggest that the evolution from a H. fulva-like ancestor to H. citrina was not a continuous process by accumulation of minute mutations.     

Somatic embryogenesis from leaf callus derived from mature trees of the cycad Ceratozamia hildae (Gymnospermae)

A friable and transient embryogenic callus was initiated from pinnae removed from leaves in new vegetative flushes of mature Ceratozamia hildae Landry & Wilson, a cycad. Somatic proembryos developed from the callus approximately 3 months after explanting onto plant growth medium consisting of a modified B5 formulation with 60 g l^-1 sucrose, 400 mg l^-1 glutamine, 100 mg l^-1 arginine, 100 mg l^-1 asparagine, 4.5 M 2,4-dichlorophenoxyacetic acid with either 1.2 M or 4.6 M kinetin and 1.75 g l^-1 gellan gum. Following subculture of somatic proembryos at this time onto medium without plant growth regulators, they continued to proliferate by a process resembling cleavage embryony or polyembryogenesis for several months. Proliferating embryogenic cultures consisted of hyperhydric somatic proembryos. Some 15 months after explanting, the somatic proembryos began to change in appearance; the suspensors became white and opaque, but were usually highly branched due to cleavage embryony. A single cotyledonary somatic embryo usually developed from the tip of each of the suspensors. Somatic embryos were primarily dicotyledonous, and less frequently monocotyledonous. Fewer than 10% of the somatic embryos appeared to be morphologically abnormal. Germination occurred in vitro whereby the coleorhiza elongated and a tap root emerged; however, plantlet recovery has not been demonstrated because the shoot axis failed to elongate.Abbreviations 2,4-d 2,-4-dichlorophenoxyacetic acid     

Adventitous bud induction in vitro from juvenile leaves of Cupressus arizonica Green

Juvenile leaves of Cupressus arizonica Green (3–5 mm in length) from eight week old seedlings, were cultured on liquid medium supplemented with isopentenyladenine (2 mgl^-1). Buds formed from the explants after three weeks of culture, but further growth occurred only after transfer to half-strength medium without plant growth regulators. Histological analysis at different times of culture, showed an early mitotic activity within transfusion tissue, followed by dedifferentiation of epidermal and mesophyll parenchyma cells at the basal zone of the leaves. The differentiation of vascular nodules always preceded bud formation. The difficulty of conifers to root and grow beyond plantlet stage is discussed.     

In vitro regeneration of cereals based on multiple shoot induction from mature embryos in response to thidiazuron

The in vitro competency of mature cereal embryos (winter, spring and durum wheats, oat, barley and triticale) was assessed for direct multiple shoot production on culture media containing the plant growth regulators, thidiazuron (TDZ) and/or 6–benzylaminopurine (BAP). Mature embryos of CDC Dancer oat showed the best response, with 69 shoots per explant on culture medium containing a combination of 4.5 μM TDZ and 4.4 μM BAP. TDZ alone induced about 16 shoots per explant from the oat. Among the wheat genotypes, durum wheat showed the most number of shoots (35) per explant on culture medium containing 4.5 μM of TDZ and 4.4 μM of BAP. With TDZ alone, shoot regeneration for durum wheat ranged from 27–32 shoots per explant. The regeneration frequency from the three winter wheat genotypes ranged from 11–25 shoots per explant and was highest on culture medium containing 9.1 μM TDZ and 4.4 μM BAP. The latter culture medium was also effective for a triticale genotype, inducing 34 shoots per explant. The regeneration from mature embryos of barley genotypes ranged from 5–9 shoots per explant. The mature embryos of all the cereals tested could be used for in vitro regeneration with TDZ and TDZ+BAP combinations.     

Ethylene as an endogenous inhibitor of root regeneration in tomato leaf discs cultured in vitro

We examined ethylene effects on root regeneration in tomato leaf discs cultured in vitro. Applied ethylene or Ethephon did not stimulate rooting in the leaf discs. In the presence of indoleacetic acid. 5 × 10^-6M, these substances significantly inhibited root formation. Ethylene production (nl C₂H₄· (24 h)^-1. flask^-1) was positively correlated with increased IAA concentrations at various times during the culture period and, as a consequence, with the rooting response after 168 h. However, separate testing of equimolar concentrations of seven different auxins and auxin-like compounds showed no positive correlation between the rate of ethylene production and subsequent rooting response. Aeration of gas-tight flasks containing leaf discs and absorption of ethylene evolved from the discs by mercuric perchlorate in gas-tight flasks or pre-treatment of leaf discs with AgNO₃ significantly enhanced IAA induced root regeneration. Thus, these studies indicate that ethylene is not a rooting hormone per se. Furthermore, ethylene (whether applied externally or synthesized by the tissue) does not appear to account for the ability of auxin to stimulate rooting.     

Effect of repeated severe pruning on endogenous polyamine content in hazelnut trees

Endogenous polyamine content was determined in leaves and buds of adult and repeatedly severe pruned hazelnut trees ( Corvlus avellana L.). Polyamine content in leaves from shoots obtained by forced outgrowth of branches taken from adult and pruned trees was also determined. Variations of polyamine levels in relation to pruning treatments were observed in all the analysed, tissues. Free polyamines increased in response to pruning treatments, mostly due to an increase in free putrescine. Free spermidine and spermine seemed to decrease with pruning intensity, whereas bound polyamines did not seem to correlate with treatments. Significantly, in all the analysed tissues the putrescine to spermidine plus spermine ratio increased in the free polyamine fraction. The results indicate that polyamine metabolism could play a role as a physiological marker for juvenility and rejuvenation in relation to cloning of woody plants. The possible role of polyamines in mediating and/or regulating phase change and reinvigoration is discussed.     

Differential expression of a chlorophyll a/b binding protein gene and a proline rich protein gene in juvenile and mature phase English ivy (Hedera helix)

Two cDNA clones representing mRNAs which are differentially expressed during in vitro culture of juvenile and mature leaf petioles of English ivy ( Hedera helix L.) were isolated by differential screening. The mRNA represented by clone HW101 is expressed at a higher level in untreated juvenile than in untreated mature in-vitro-cultured petioles. Treatment of petioles with α-naphthaleneacetic acid (NAA) at the initiation of culture decreases HW101 mRNA levels in juvenile but not mature, petioles. In intact plants. HW101 mRNA is expressed at a higher level in juvenile laminae, petioles and stems than in identical tissues of mature plants. DNA sequence analysis indicates that HW1O1 cDNA is significantly similar to a light harvesting chlorophyll a/b binding protein gene ( Lhcb ) of pea. The gene represented by the second clone. HW103, is expressed at a higher level in mature than in juvenile in-vitro-cultured petisoles. Treatment of petioles with NAA at the initiation of culture decreases HW103 mRNA levels in chronologically young mature but not older mature and juvenile petioles. However, expression of the HW103 gene is not detectable in petioles, or in any other vegetative organ tested, immediately after excision. It is, however, expressed in developing seeds. In otherwise intact plants, the HW103 gene is expressed in wounded petioles of mature plants 5 days after wounding but not in wounded petioles of juvenile plants. It is also expressed at a higher level in wounded stems of mature plants than in those of juvenile plants. However, it is not expressed in wounded lamina of either juvenile or mature plants. DNA sequence analysis indicates that HW103 cDNA is similar to a cell wall proline rich protein (PRP) gene of soybean. This is the first report of differential expression of a PRP gene in tissues from juvenile and mature plants. Southern blot analysis of nuclear DNA of H. helix shows that both HW101 and HW103 are members of small gene families.