Jeung Keun Suh

Evaluation of Curcuma as potted plants and cut flowers

Summary Sixteen accessions of Curcuma germplasm that included C. alismatifolia ‘Chiang Mai Pink’, and ‘Lady Di’ and C. thorelii ‘Chiang Mai Snow’ and C. alismatifolia ‘Pink’, C. parviflora ‘White Angel’, and C. sp. ‘CMU Pride’ were evaluated for use as potted plants or as cut flowers. All cultivars of C. alismatifolia and C. thorelii ‘Chiang Mai Snow’ were considered suitable for cut-flower and pot-plant use, respectively. C. parviflora ‘White Angel’ also proved to be a suitable cultivar for potted plant production. Optimum storage temperatures for rhizomes in relation to greenhouse forcing and ethanol-soluble glucose, fructose and sucrose concentrations were determined. Storing rhizomes at 25° – 30°C for 2 – 3 months after harvest is recommended to break dormancy. Plants of C. parviflora ‘White Angel’ flowered 50 – 89 d after potting and can be used as potted plants. Plants of C. alismatifolia flowered 96 – 133 d after potting, with floral stem-lengths suitable as cut flowers. High levels of boron or manganese were correlated with burn symptoms at the margins of the leaves [‘leaf-margin burn’ (‘LMB’)] and were observed in old leaves of ‘CMU Pride’ at flowering. Levels of ethanol-soluble fructose, glucose and sucrose in the tuberous roots of Curcuma were higher than the levels in rhizomes, and increased as storage temperatures increased. Accelerated leaf emergence from rhizomes stored at 30°C took 16 d and was associated with increases in glucose and fructose contents. Very similar morphological characters between C. thorelii ‘Chiang Mai Snow’ and C. parviflora ‘White Angel’ emphasised that identification of Curcuma accessions using DNA-markers is required for future studies.

Identification and evaluation of Forsythia germplasm using molecular markers

This study identifies Forsythia germplasm and evaluated the genetic relationships of F. ×intermedia hybrids, cultivars and their putative parental species. Leaf samples of F. ×intermedia cultivars and species, such as F. koreana and F. suspensa, were collected in the Netherlands, Korea, and USA. Total genomic DNA was extracted and evaluated by randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) analyses. Dendrograms were constructed by using the neighbor-joining (NJ) clustering algorithm applying the interior branch (IB) test or analyzed by STRUCTURE. In the dendrogram generated by RAPD markers, two major clusters were observed. One cluster (CL-I) contained most of the F. ×intermedia cultivars, F. suspensa, and F. koreana. The other cluster (CL-II) included F. europaea, F. ovata, F. densiflora, F. mandshurica, F. japonica, F. viridissima, and cultivars derived from F. ovata. In the AFLP dendrogram, the placement of F. ×intermedia cultivars with F. suspensa was similar, forming cluster CL-A I. The RAPD and AFLP results clearly separated most F. ×intermedia cultivars from F. ovata derived cultivars. The full range of genetic diversity of F. suspensa and F. viridissima should be investigated to verify whether these two species are truly parental taxa for F. ×intermedia. Placement of F. viridissima, F. ovata, and F. japonica in different sub-clusters requires further investigation regarding genetic diversity in the species, and their close relationship with F. koreana, F. mandshurica, and F. saxatalis.

Growth and flowering physiology, and developing new technologies to increase the flower numbers in the Genus Lilium

The genus Lilium is important as potted plants or cut flowers for horticultural trade and for gardens. However, most of the extensive research on the growth and flowering of this genus was conducted with L. longiflorum Thunb. (Easter lily) forcing large bulbs grown in the field for at least one or two years. Dormancy had to be broken to induce flowering by cold treatment which was given to mature bulbs (vernalization). It would be desirable if the bulb production phase could be bypassed to shorten the total production time, ideally by manipulating the temperature during the bulb programming phase (vernalization methods) and the early greenhouse forcing phase (from potting to flower bud initiation). Information on the physiology of bulb development, controlled flowering, and timing for the Easter, and to certain extent for the Asiatic hybrid lily is readily available. However, information on LA, L. longiflorum × Oriental (LO), and Oriental × Trumpet (OT) hybrid lilies, is not available. The objective of this article is to review factors that control flower numbers and speed of flowering, and to present outlines for producing quality plants of L. longiflorum, L. ×elegans, and LA hybrids, starting from seeds, stem bulbils, and tissue cultured plants, respectively, in a year. Detailed information on the production of L. ×elegans starting from stem bulbils is presented. Cut flowers of Asiatic hybrid ‘Beni no Mai’ with 2 to 3 flowers and strong 60 cm stems were produced in less than a year when mature bulbils, weighing about 400 mg harvested 40 to 50 days after flowering, are treated with a sequential temperature treatment (SEQ CD) 14 to 20 days each at 5°C-15°C-5°C. This production period can be divided into plug production phase from potting the treated bulbils shoot emergence lasting about 200 to 230 days and the second phase from shoot emergence to flowering requiring 90 to 100 days. The increase in the number of flowers could result from the increased shoot apex size and not from the changes in soluble and cell wall neutral sugars.

Species relationships of Lycoris endemic to Korea evaluated by RAPD and SNPs of nrDNA-ITS regions

This study was performed to investigate the species relationships and variation of Lycoris Herb. (Amaryllidaceae) species using random amplification of polymorphic DNA (RAPD) markers. Also, single nucleotide polymorphisms (SNPs) of internal transcribed spacer 1, 5.8S ribosomal RNA gene and internal transcribed spacer 2 regions in Lycoris sanguinea var. koreana were analyzed. All accessions formed 6 major clusters; cluster A with all L. sanguinea and L. chejuensis; cluster B with 3 accessions of L. flavescens; cluster C with 8 accessions of F. flavescens var. flavescens; cluster D with 10 accessions of L. uydoensis; cluster E with L. chinensis var. sinuolata and 4 accessions of L. uydoensis; and cluster F with all L. radiata. Five haplotypes were observed; L. sanguinea and L. chejuensis having the haplotype 1 with bases of CTTATATATAT; L. chinensis var. sinuolata and all L. flavescens. Lycoris incarnata and L. aurea, non-endemic to Korea had haplotype 2 and 5, respectively. Genetic variations in L. flavescens, L. chinensis var. sinuolata, and L. uydoensis are revealed based on the analysis of molecular variances (AMOVA) and haploid types analyzed by sequence analysis. It is suggested that L. chejuensis may result from hybridization involving L. sanguinea var. koreana due to a close affinity between L. sanguinea complex and L. chejuensis. Nomenclature for L. chejuensis and L. flavescens whether they should be described as a hybrid origin should be discussed in the future.

A hybrid swarm population of Pinus densiflora × P. sylvestris inferred from sequence analysis of chloroplast DNA and morphological characters

To confirm a hybrid swarm population of Pinus densiflora × P. sylvestris in Jilin, China, we used needles and seeds from P. densiflora, P. sylvestris, and P. densiflora × P. sylvestris collected from natural stands or experimental stations to study whether shoot apex morphology of 4-year old seedlings can be correlated with the sequence of a chloroplast DNA simple sequence repeat marker (cpDNA SSRs). Total genomic DNA was extracted and subjected to sequence analysis of the pine cpDNA SSR marker Pt15169. Results show that morphological characters from 4-year old seedlings did not correlate with sequence variants of this marker. Marker haplotypes from all P. sylvestris trees had a CTAT element that was absent from all sampled P. densiflora trees. However, both haplotype classes involving this insertion/deletion element were found in a P. densiflora × P. sylvestris population and its seedling progeny. It was concluded that the P. densiflora × P. sylvestris accessions sampled from Jilin, China resulted from bi-directional crosses, as evidenced by both species’ cpDNA haplotypes within the hybrid swarm population.

Effect of Warm and Cold Stratification on 1 H-NMR Profiles, Endogenous Gibberellins and Abscisic Acid in Styrax japonicus Seeds

Germination of Styrax japonicus seeds is promoted by warm stratification (WS) at 18–20°C followed by cold stratification (CS) at 4–5°. The objective of this work was to analyze the state and mobility of water molecules measured by 1H-NMR and endogenous gibberellins (GAs) and abscisic acid (ABA) by ultra performance liquid chromatography/mass spectrometry/mass spectrometry (UPLC-MS/MS) as influenced by WS and CS treatments had not previously been investigated. Styrax seeds that received 35 days of WS (35D WS) followed by 63 days of CS (63D CS) (35D WS + 63D CS) germinated. Seeds that received only 35D WS failed to germinate. Endogenous GA1, GA8, GA19, GA20, and GA53 were identified as well as GA17, GA23, GA28, GA29, and GA97 by gas chromatography/MS (GC/MS) and UPLC-MS/MS in seeds that were treated with warm and cold stratification (WS + CS). This suggests that the early C-13 hydroxylation pathway [-GA53-(GA44)-GA19-GA20-GA1-GA8] of GAs is a major biosynthetic pathway in the seeds. The concentration of GA53 and GA19 increased following WS and that of GA53 increased after WS + CS. The concentration of GA19 increased only slightly after WS + CS. The concentration of GA1 increased only after WS + CS. ABA concentration significantly decreased following the WS treatment. It is concluded that the mobility of water molecules and water content in cotyledons and endosperm is increased following WS + CS treatments. The occurrence of C-13 hydroxylated GAs suggests that the early C-13 hydroxylation pathway, → GA53 → GA44 → GA19 → GA20 → GA1 → GA8, is a major biosynthetic pathway in Styrax seeds.

Optimum Nutrient Level on Growth, Flowering, and Rhizome Production in Curcuma

ABSTRACT This study investigated the effect of liquid fertilizer treatments on growth, flowering, leaf mineral content, and rhizome production during forcing of Curcuma alismatifolia ‘Chiang Mai Pink’ and C. thorelii ‘Chiang Mai Snow’. Plants were irrigated with 200 mL of 1.3 g L−1 of 15 nitrogen (N) -7 phosphorus (P) -14 potassium (K) water soluble fertilizer at 0, 1.3, 2.7, 4.0, 5.3, or 6.6 g L−1 weekly. Days to flower, flower stem length, and leaf length were recorded, the mineral contents in leaves were analyzed, and the number of rhizomes with tuberous roots were recorded at harvest. Flowering of the first inflorescence in both C. alismatifolia ‘Chiang Mai Pink’ and C. thorelii ‘Chiang Mai Snow’ was significantly delayed when plants received 6.6 g L−1 fertilizer as compared to the control plants. The number of rhizomes with more than 4 tuberous roots was highest when plants received 2.7 g L−1 fertilizer. No medium-sized rhizomes with more than seven tuberous roots were produced when ‘Chiang Mai Pink’ plants received 0, 4.0, 5.3, and 6.6 g L−1 fertilizer. Based on the production of rhizomes with four to six tuberous roots, optimum concentration of 15N -7P -14K water soluble fertilizer is 2.7 g L−1 for C. alismatifolia ‘Chiang Mai Pink’ and 1.3 to 4.0 g L−1 for C. thorelii ‘Chiang Mai Snow’. Although high boron content occurred only in the outer part of the second leaf when fertilizer concentrations were increased, leaf-margin burn (LMB) symptoms were not observed in both species and this could not be related to the production of rhizomes.

Identification of Ligustrum Seedlings Based on Sequence Analysis of an Internal Transcribed Spacer

Two-year old seedlings derived from a Ligustrum quihoui plant (NA56612.01) showed variation in leaf sizes, and the leaf sizes of several L. quihoui seedlings were significantly larger than other seedlings, suggesting that possibility of interspecific hybridization with L. japonicum or L. foliosum which were maintained sympatrically with the L. quihoui at the repository. However, the leaves of seedlings were smaller than those of mature L. quihoui plants, thus requiring the use of molecular markers to verify any possible hybridization. Based on the sequence analysis of the nuclear internal transcribed spacers 1, 2 in ribosomal RNA gene (ITS 1, 2 region), the sequence of all seedlings showed 100% homology and perfectly matched with the L. quihoui accession, but not with L. japonicum or L. foliosum. These data suggested that the seedlings were not resulted from interspecific hybridization, but from intra-pollination among the L. quihoui progeny. Genetic purity of the L. quihoui can be maintained among seedlings obtained from the mother plant. This is an important feature for ex situ germplasm conservation of L. quihoui.

Growth and flowering responses of Anigozanthos hybrids influenced by plant age, temperature, and photoperiod treatments

Growth and flowering responses of Anigozanthos hybrids, ‘Regal Claw’ and A. manglesii × A. flavidus, were investigated starting from in vitro propagated propagules. Flowering of 9-week old ‘Regal Claw’ was less than 50% from the main fan (MF) when plants received 21.0°C during day and 13.0°C at night (21.0/13.0°C, day/night). Flowering of 20-week old ‘Regal Claw’ and A. manglesii × A. flavidus hybrids either from the MF or the lateral fans (LF) was accelerated when plants received 21.0/13.0°C regardless of photoperiod treatment. Flowering from the lateral fans was accelerated when plants received 8 hours of long day photoperiod (LD) treatment as a day-extension provided from incandescent light bulbs at 21.0/15.5°C and 21.0/18.0°C. Fewer than 2.5 total branches per inflorescence were produced from the MF grown at 18.0°C as compared to more than 4.0 total branches produced at 13.0°C. Plants must be 20-week old to flower from both the MF and the LF. The optimum temperature for early flowering and for an increased quality of cut flowers was considered to be 13.0°C, and at this inductive night temperature for flowering, ‘Regal Claw’ and A. manglesii × A. flavidus are considered as a day neutral, while at 15.5°C and 18.0°C, they are considered as a quantitative long day (LD) plant.

Dehydration intolerant seeds of Ardisia species accumulate storage and stress proteins during development

Seeds of two commercially marketable small shrubs, Ardisia crenata and Ardisia japonica, do not germinate if they are stored for more than few weeks in conditions where they are allowed to dehydrate, and they are considered as recalcitrant. The berries of these plants remain attached for a long period of time after an approximately 34 weeks period of development. The proteins in the developing seeds, germinating seeds, and seeds stored for various periods of time in moist or dry conditions and at 10°C or 25°C were examined by a polyacrylamide gel electrophoresis and an immunoblot analysis with antibodies to dehydrin and oleosin. Both dehydrin- and oleosin-like proteins were detected in early stages of seed development, as were proteins that are likely to function as seed storage proteins. Storage of seeds in dry conditions induced the expression of both dehydrin- and oleosin-like proteins, but only after an 8 weeks storage period. The levels of these proteins were considerably lower in the less dehydration tolerant A. japonica.