Nellie White Research Articles

Field test of Easter lilies transformed with a rice cystatin gene for root lesion nematode resistance.

Easter lilies, Lilium longiflorum cv. Nellie White are a staple of the floral industry. In the U.S. most of the Easter lilies are grown in Oregon and California along the coast where there is a micro climate that is favorable to growth of lilies. The main pest when growing lilies in the field is Pratylenchus penetrans, the root lesion nematode. Easter lilies are one of the most expensive crops to produce because of the cost of chemicals used to control P. penetrans and other pathogens that infect the lilies. Our previous study had shown that transgenic Easter lilies containing a rice cystatin gene (Oc-IΔD86 that has a deleted Asp86) were resistant to P. penetrans in vitro. This study examined growth characteristics of five independently transformed lines of the cystatin Easter lilies compared to non-transformed Nellie White for three seasons in the field in Brookings, Oregon. Liles grown in three soil chemical treatments 1) preplant fumigation, 2) preplant fumigation plus at plant organophosphate, and 3) at plant organophosphate were compared to those grown in nontreated soil. Growth characteristics evaluated included: time of shoot emergence, survival of plants, size of plants, visual ratings of plant health, basal roots and stem roots, weight of foliage and roots, and number and size of bulblets that developed on stems. Nematodes were counted following their extraction from the roots. While not totally resistant, when planted in the field, transformed lines demonstrated and maintained a degree of resistance to lesion nematode over two growing seasons and displayed desirable growth and quality characteristics similar to non-transformed lilies.

First Report of Lily Root Rot Caused by Thanatephorus cucumeris AG 2-1 in the United States

A survey was undertaken on April 2016 to profile soilborne fungal pathogens causing root rot and lesions on lily (Lilium longiflorum) cv. Nellie White in Brookings, Curry County, Oregon. Diseased roots were either blackened or rotted. Sections of diseased roots including the epidermis were surface sterilized and placed on sterile water agar plates containing 100 μg/ml chloramphenicol. From the emerging mycelia, pure cultures were obtained by collecting hyphal tips and placing them on potato dextrose agar (PDA) medium. Recently, we demonstrated the presence of pathogenic Fusarium oxysporum, F. tricinctum, and Ceratobasidium sp. AG-I isolates in eight randomly selected fungal isolates from diseased roots of lilies (Lakshman et al. 2017). In this investigation, three additional fungal isolates showed four to six nuclei per cell under the microscope with lactophenol staining at 400× magnification. The hyphae were branched at right angles, and septa were present near the point of branching. The respective fungal isolates produced dark brown microsclerotia of 2 mm or less in diameter, mostly at the edge of PDA plates. Total DNA from each of the three cultures was PCR amplified with ITS1 and ITS4 ribosomal DNA (rDNA) primers (White et al. 1990) and cloned into a TOPO TA cloning vector (Thermo Fisher Scientific, Waltham, MA). Nucleotide sequences of a randomly chosen clone from each of the three isolates were 706 bp long and identical in sequence. Hence, all were assumed to have originated from a single haplotype and numerated as ELRF 11. The rDNA amplicon deposited in GeneBank (accession no. MF972486) showed 100% homology with the corresponding region of two isolates of Rhizoctonia solani (Teleomorph: Thanatephorus cucumeris) anastomosis group (AG) 2-1 (gb|KP662692 and gb|JQ676881). For pathogenicity tests, 5-mm-diameter plugs from the margin of a 5-day-old culture were placed near the roots of axenically grown lily seedlings, two replicates per treatment and repeated two times, for 10 days at 22°C. Necrotic brown lesions appeared on the roots of such seedlings whereas control inoculation with only PDA plugs did not produce any symptoms on roots. Lactophenol staining and microscopy showed both inner and outer mycelia colonization on infected roots. Additionally, the ELRF 11 caused necrosis and rot upon inoculation of roots of diploid strawberry runners (Hawaii4 F7-3) and necrotic spots on detached leaves of Nicotiana glutinosa, N. benthamiana, and N. paniculata. The onset of necrotic symptoms on those plants occurred 4 to 7 days after inoculation. Fungus with identical morphology was reisolated from root lesions, thus proving Koch’s postulate. No fungus could be isolated from respective roots and leaves of control seedlings. AG 2-1 isolates are reported to be pathogenic on roots, bulbs, and leaves of various hosts, including strawberry and Nicotiana spp. (Yang and Li 2012). Furthermore, both pathogenic and nonpathogenic isolates of AG 2-1 were reported on bulbous crops in the Netherlands (Schneider et al. 1997). To our knowledge, this is the first report of T. cucumeris AG 2-1 causing root rot of lily in the field plots of Oregon or anywhere else in the United States. As various AGs may differ in sensitivity to fungicides and biocontrol agents (Amaradasa et al. 2014), a systematic survey of Rhizoctonia and other pathogens infecting lily under field conditions is required in order to develop effective disease management strategies.

Symptom Development in Response to Combined Infection of In Vitro-grown Lilium longiflorum with Pratylenchus penetrans and Soilborne Fungi Collected from Diseased Roots of Field-grown Lilies

Eight fungal isolates (ELRF 1 to 8) were recovered from necrotic roots of Easter lilies, Lilium longiflorum cv. Nellie White, grown in a field in the U.S. Pacific Northwest. The eight fungal isolates were identified by sequencing and molecular phylogenetic analyses based on their ITS rDNA region. Five isolates were identified as Fusarium oxysporum, two as F. tricinctum, and one as Rhizoctonia sp. AG-I. This constitutes the first report of Rhizoctonia sp. AG-I infecting lilies worldwide and the first report of F. tricinctum infecting lilies in the United States. To study and validate their pathogenicity, pure cultures of each isolate were used to infect the roots of Easter lily plants growing in vitro. In addition, Easter lily plants growing in vitro were infected either with or without Pratylenchus penetrans, the root lesion nematode, prior to placing a culture plug of fungus 1 cm from a lily root. Pratylenchus penetrans is a nematode species commonly found in the sampled fields. The presence of both nematode and Rhizoctonia sp. AG-I isolate ELRF 3 in infected lilies was evaluated by molecular analyses, confirming the infection of roots 3 days after inoculation, prior to development of disease symptoms. Necrosis and root rot developed more rapidly with all eight fungal isolates when there had been prior infection with P. penetrans, the major nematode parasitizing Easter lily roots in the field in Oregon.

Characterization of Lilium longiflorum cv. 'Nellie White' Infection with Root-lesion Nematode Pratylenchus penetrans by Bright-field and Transmission Electron Microscopy.

Lilium longiflorum cv. Nellie White, commonly known as Easter lily, is an important floral crop with an annual wholesale value of over $26 million in the United States. The root-lesion nematode, Pratylenchus penetrans, is a major pest of lily due to the significant root damage it causes. In this study, we investigated the cytological aspects of this plant-nematode interaction using bright-field and transmission electron microscopy. We took advantage of an in vitro culture method to multiply lilies and follow the nematode infection over time. Phenotypic reactions of roots inoculated with P. penetrans were evaluated from 0 to 60 d after nematode infection. Symptom development progressed from initial randomly distributed discrete necrotic areas to advanced necrosis along entire roots of each inoculated plant. A major feature characterizing this susceptible host response to nematode infection was the formation of necrosis, browning, and tissue death involving both root epidermis and cortical cells. Degradation of consecutive cell walls resulted in loss of cell pressure, lack of cytoplasmic integrity, followed by cell death along the intracellular path of the nematode's migration. Pratylenchus penetrans was never seen in the vascular cylinder as the layer of collapsed endodermal cells presumably blocked the progression of nematodes into this area of the roots. This study presents the first detailed cytological characterization of P. penetrans infection of Easter lily plants.

Expression of a cystatin transgene can confer resistance to root lesion nematodes in Lilium longiflorum cv. ‘Nellie White’

Lilium longiflorum cv. 'Nellie White' assumes a great economic importance as cut flowers, being one of the most valuable species (annual pot plants value above $20,000,000) in terms of wholesales in the US. The root lesion nematode Pratylenchus penetrans (RLN) constitutes one of the main pests for lily producers due to the significant root damage it causes. Our efforts have focused on the generation of soybean hairy roots (as a transient test model) and stable transgenic lilies overexpressing a modified rice cystatin (Oc-IΔD86) transgene and challenged with root lesion nematodes. Lily transformation was achieved by gene gun co-bombardment using both a pBluescript-based vector containing the cystatin gene and pDM307 that contains a bar gene for phosphinothricin selection. Both soybean hairy roots and lilies overexpressing the OcIΔD86 transgene exhibited enhanced resistance to RLN infection by means of nematode reduction up to 75 ± 5% on the total number of nematodes. In addition, lily plants overexpressing OcIΔD86 displayed an increase of plant mass and better growth performance in comparison to wild-type plants, thereby demonstrating an alternative strategy for increasing the yield and reducing nematode damage to this important floral crop.

Long term, transgene expression in Lilium longiflorum ‘Nellie White’ grown outdoors and in the greenhouse

Lilium longiflorum cv. Nellie White plants were transformed with either the bar-uidA fusion gene or the nptII and uidA genes and grown for two seasons in the greenhouse and outdoors in containers. All transgenes were under control of the CaMV 35S promoter. During the first year there was no difference in bar protein level between plants grown in the greenhouse and outdoors, but the second year two of the seven transgenic plant lines grown outdoors showed a significantly higher level of the bar protein than plants grown in the greenhouse. The relative level of bar protein expression between all seven transgenic plant lines remained the same for lilies grown in the greenhouse and outdoors during two growing seasons. One plant line contained the nptII gene, and nptII protein expression was comparable when plants were grown in the greenhouse or outdoors for two seasons. Four plant lines expressed GUS as determined by histochemical staining of their leaves. Three of these four plant lines showed dark blue staining along the cut edges of the leaf when plants were grown either in the greenhouse or outdoors for both seasons. The fourth plant line showed either dark blue staining along the cut edge of the leaf or small, light blue spots on parts of the leaf depending on the plant stained. Expression of the three genes was confirmed using semi-quantitative RT-PCR.

Biolistic-mediated Transformation of Lilium longiflorum cv. Nellie White

Slow-growing compact calluses were initiated from bulb scales of Lilium longiflorum cv. Nellie White that had been cultured for at least 6 months on Murashige and Skoog (MS) medium with 9 μm dicamba. To develop a reliable selection system, the sensitivity of nontransformed calluses and in vitro plants to different selective agents such as phosphinothricin, kanamycin, geneticin, paromomycin, and hygromycin was tested when grown on MS medium. Nontransformed calluses showed high sensitivity to 0.5 mg·L−1 phosphinothricin, 25 mg·L−1 geneticin, and 5 mg·L−1 hygromycin. Nontransformed plants grown in vitro died on either 2 mg·L−1 phosphinothricin or 75 mg·L−1 hygromycin. Plants did not die when grown on either 200 mg·L−1 kanamycin or 100 mg·L−1 geneticin, and 100 mg·L−1 paromomycin stimulated plant growth. Transformation was achieved using biolistics on callus bombarded with either the bar-uidA fusion gene under control of the CaMV 35S promoter or npt II and uidA under control of the CaMV 35S promoter. One week after biolistic bombardment, callus bombarded with the bar-uidA fusion gene was cultured for 1 month on MS medium supplemented with 9 μm dicamba and 0.1 mg·L−1 phosphinothricin and then transferred to 0.2 mg·L−1 phosphinothricin for 1 month followed by 1.0 mg·L−1 for the next 4 months. Regenerating shoots and well-established plants were cultured on MS medium lacking hormones and with either 0.2 mg·L−1 or 2.0 mg·L−1 phosphinothricin, respectively. Callus bombarded with the npt II gene was cultured on MS medium with 50 mg·L−1 geneticin until shoots regenerated. Regenerated shoots were cultured on MS medium lacking hormones. Under optimal conditions, 10 transgenic plants were selected from seven plates of callus bombarded with the bar-uidA fusion gene using phosphinothricin for selection. Both Southern hybridization of genomic DNA and polymerase chain reaction analysis verified the presence of the transgene in transformed ‘Nellie White’ plants. Transgenic plants were phenotypically normal, and they were crossed with nontransformed plants of L. longiflorum cvs. Sakai, Yin tung, Sakai, and Flavo. The presence of the bar gene in 41% of the T1 progeny plants confirmed stable integration of the transgene into the genomic DNA of transgenic lily plants. β-glucuronidase expression resulting from the uidA gene was demonstrated in leaves and roots of some of the transgenic lily plants by histochemical staining, determination of the specific activity of the β-glucuronidase enzyme, and Northern hybridization.

Lilium longiflorum 'Nellie White'의 인편으로부터 Friable 배발생 캘러스를 통한 소자구 분화

A series of experiments were performed to establish regeneration system through friable embryogenic callus (FFC) of Lilium longiflorum `Nellie White`. Only hard and regular callus was induced from bulb scales on medium containing 2.0 mg/L dicamba and g/L sucrose. The induced hard callus was subcultured on medium with 2.0 mg/L dicamba and 30 g/L sucrose, and used as a material for induction of FEC. In order to induce FEC, induced hard and regular callus was chopped into segments, and re-cultured on medium with 2.0 mg/L dicamba and 90 g/L sucrose. FEC was induced from chopped hard calli by the subcultures of two months interval. The induction rate of FEC was enhanced when hard callus was subcultured on same medium. FEC was proliferated more than 5 times on medium with dicamba and 90 g/L sucrose. Bulblet differentiation from FEC was very favorable on MS medium supplemented with 0.1 mg/L BA, 1.0 mg/L NAA and 30 g/L maltose, but many differentiated bulblets were changed to vitrificated ones. The differentiation of normal bulblets was most effective on medium containing activated charcoal and 30 g/L sucrose.

Irrigation Method and Temperature of Water Affect Height of Potted Easter Lilies

Potted greenhouse-forced `Nellie White' Easter lilies (Lilium longiflorum Thunb.) were irrigated from emergence with water at 2, 5, 8, 11, or 15 °C either onto the shoot apex (overhead) or onto the substrate for a 0, 2-, 4-, 6-, 8-, 10-, or 12-week period. Control treatment was at 18 °C, either overhead or on substrate. When irrigation water was applied overhead for the entire period between emergence and flowering (12 weeks), plant height increased linearly with the temperature of irrigation water (1.75 cm/°C). As the period of application with cold water increased from 0 to 12 weeks, plant height decreased both in a linear and a quadratic manner. Forcing time was negatively correlated with height with the shortest plants delayed by 3 to 6 days. Water temperature did not affect bud abortion or the number of yellow leaves. Irrigation water temperature had no effect on plant parameters when applied directly on the substrate.

Quantifying the Cooling Period for Flowering of 'Nellie White' Easter Lily

In the commercial development of an innovative process for the production of pathogen-indexed Easter lilies (Lilium longiflorum Thunb.) in less than a year, it became desirable to quantify the cooling period so that the time of flower induction/initiation could be determined. Based upon studies of forcing flowering plants from bulbs, I hypothesized that cooling could be quantified using the cool temperature unit (CTU), defined as 1 °C below 21 °C for 1 hour, and the warm temperature unit (WTU), defined as 1 °C above 21 °C for 1 hour. The purpose of these studies was to determine if the hypothesis was valid. With 'Nellie White' Easter lily, it was determined that cooling could be quantified as hypothesized. The minimum threshold number of CTU that would induce flowering in at least one plant of the test population after exposure to long days was between 1200 and 2400, whereas the threshold number of CTU that would induce flowering in 100% of the population was 3600. The optimum threshold, i.e., the number of CTU that would result in the best market quality, was estimated to be 4800. The studies demonstrate that market quality, pathogen-indexed flowering potted Easter lilies growing continuously from bulblets can be produced in about 1 year, and that the cooling required to sensitize the plants to long days, which is central to the success of the fast production process, is quantifiable.

098 Effect of Storage Duration on Easter Lily Carbohydrate Concentration and Postharvest Flower Longevity

Case-cooled bulbs of Lilium longiflorum `Nellie White' were forced to flowering. When the tepals on the first primary flower bud split, plants were placed at 2 °C in the dark for 0, 4, or 21 days. After storage, plants were placed in a postharvest evaluation room with constant 21 °C and 18 μmol·m-2·-1 cool-white fluorescent light. Lower leaves, upper leaves, and tepals of the first primary flower from a concurrent set of plants were harvested for carbohydrate analysis using HPLC. Storage time did not affect carbohydrate levels in the lower leaf or tepal samples, but sucrose and starch levels decreased while glucose and fructose levels increased in the upper leaf tissue with increasing storage time. These changes were correlated with a decrease in postharvest longevity for the first four primary flowers. Longevity of the fifth primary flower and total postharvest life of the five primary flowers was unaffected by storage.

Ancymidol Drenches, Reversed Greenhouse Temperatures, Postgreenhouse Cold Storage, and Hormone Sprays Affect Postharvest Leaf Chlorosis in Easter Lily

The interactions of ancymidol drenches, postgreenhouse cold storage, and hormone sprays on postharvest leaf chlorosis and flower longevity of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) were investigated. Ancymidol drenches (0.5 mg/plant twice) during early growth resulted in leaf chlorosis in the greenhouse which intensified further during postharvest. Cold storage (4 °C) of puffy bud stage plants for 2 weeks also accelerated leaf chlorosis. The combination of ancymidol treatment with cold storage resulted in the most severe leaf chlorosis. Promalin (GA4+7 and BA each at 100 mg·L-1) sprays completely prevented postharvest leaf chlorosis, whereas ProGibb (GA3 at 1000 mg·L-1) was ineffective. Cold storage reduced flower longevity and increased bud abortion, however, the degree of bud abortion varied among experiments in different years. Both ProGibb and Promalin sprays increased flower longevity. Compared to positive DIF (difference between day and night temperature) grown plants, forcing under negative DIF (-8 °C) increased the severity of postharvest leaf chlorosis. Leaves were sampled from basal, middle, and upper sections of the stem after 4 and 12 days in a postharvest evaluation room, and analyzed for soluble carbohydrates and N. Total leaf soluble carbohydrates and N concentrations were less in basal and middle sections of negative DIF-grown plants than in positive DIF-grown plants. Leaf chlorosis was associated with depletion of soluble carbohydrates and N in the leaves. Chemical names used: α-cyclopropyl-α-(p-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); gibberellic acid (GA3); gibberellins A4A7 (GA4+7); N-(phenylmethyl)-1H-purine 6-amine (benzyladenine).

Developmental regulation of the gene for chimeric calcium/calmodulin-dependent protein kinase in anthers.

Chimeric Ca(2+)/calmodulin-dependent protein kinase (CCaMK) was cloned from developing anthers of lily (Lilium longiflorum Thumb. cv. Nellie White) and tobacco (Nicotiana tabacum L. cv. Xanthi). Previous biochemical characterization and structure/function studies had revealed that CCaMK has dual modes of regulation by Ca(2+) and Ca(2+)/calmodulin. The unique structural features of CCaMK include a catalytic domain, a calmodulin-binding domain, and a neural visinin-like Ca(2+)-binding domain. The existence of these three features in a single polypeptide distinguishes it from other kinases. Western analysis revealed that CCaMK is expressed in a stage-specific manner in developing anthers. Expression of CCaMK was first detected in pollen mother cells and continued to increase, reaching a peak around the tetrad stage of meiosis. Following microsporogenesis, CCaMK expression rapidly decreased and at later stages of microspore development, no expression was detected. A tobacco genomic clone of CCaMK was isolated and transgenic tobacco plants were produced carrying the CCaMK promoter fused to the beta-glucuronidase reporter gene. Both CCaMK mRNA and protein were detected in the pollen sac and their localizations were restricted to the pollen mother cells and tapetal cells. Consistent results showing a stage-specific expression pattern were obtained by beta-glucuronidase analysis, in-situ hybridization and immunolocalization. The stage- and tissue-specific appearance of CCaMK in anthers suggests that it could play a role in sensing transient changes in free Ca(2+) concentration in target cells, thereby controlling developmental events in the anther.

Timing of Gibberellin4+7 + Benzyladenine Sprays Influences Efficacy against Foliar Chlorosis and Plant Height in Easter Lily

The effects of Promalin® [PROM; 100 mg·L–1 each of GA4+7 and benzyladenine (BA)] sprays on leaf chlorosis and plant height during greenhouse production of ancymidol-treated (two 0.5-mg drenches per plant) Easter lilies (Lilium longiflorum Thunb. `Nellie White') were investigated. Spraying with PROM at early stages of growth [36 or 55 days after planting (DAP)] completely prevented leaf chlorosis until the puffy bud stage, and plants developed less severe postharvest leaf chlorosis after cold storage at 4 °C for 2 weeks. When PROM was sprayed on plants in which leaf chlorosis had already begun (80 DAP), further leaf chlorosis was prevented during the remaining greenhouse phase and during the postharvest phase. PROM caused significant stem elongation (23% to 52% taller than controls) when applied 36 or 55 DAP, but not when applied at 80 DAP or later. The development of flower buds was not affected by PROM treatments. Although PROM sprays applied at 55 DAP or later increased postharvest flower longevity, earlier applications did not. Chemical names used: N-(phenylmethyl)-1H-purine 6-amine (benzyladenine, BA); α-cyclopropyl-α-(p-methoxyphenyl)-5-pyrimidinemethanol (ancymidol).

568 Effect of Twilight and Temperature Difference (DIF) or Temperature Pulse at End-of-day on Height of Easter Lilies

Potted bulbs of Lilium longiflorum Thunb. `Ace', `Nellie White', and `Snow White' were grown under either ambient photo period (APP), 8-h photo period using blackout (no twilight) between 1600 and 0800 HR (8PP) or 8PP extended with 1-h of low-intensity far-red radiation (9PP) at end-of-light period in a greenhouse with either a +5 °C DIF or a –5 °C DIF (= day – night temperature). In a second experiment, Easter lilies were also grown under APP, 8PP, and 9PP regimes with a constant day/night temperature (0 °C DIF) but with either a +5 °C or –5 °C temperature pulse for 3-h during end-of-light period. Each experiment was replicated twice and data was averaged over 2 years. The +5 °C DIF regime produced plants which were 19% taller than under –5 °C DIF. Plants grown under APP were 32% and 25% taller than under 8PP in the +5 °C and –5 °C DIF regimes, respectively. Regardless of the DIF regime, plant height under the 9PP was the same. In the second experiment, there was no significant difference in plant height of plants grown with the –5 °C compared with the +5 °C pulse at end-of-light period.

Spectral Filters Affect Growth, Flowering, and Postharvest Quality of Easter Lilies

The role of light quality on growth, flowering, and postharvest characteristics of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) was evaluated in two growing seasons using 4% CuSO4 and water (control) as spectral filters. The CuSO4 filter significantly reduced plant height and internode length. However, the height reduction was smaller in the 1994-95 season (9%) than in the 1995-96 growing season (32%). The number of days to flower bud appearance and flower opening, and the number and diameter of flowers were not significantly affected by the spectral filters in either season. The CuSO4 filters reduced flower longevity by 3 days in nonstored plants, and by 5 days when plants were subjected to 1 week storage at 4 °C prior to placing in the postharvest room. Results suggest that spectral filters are effective in controlling height and producing compact Easter lily plants without causing a delay in flowering or reducing number of flowers per plant but flower longevity can be adversely affected.

Spectral Filters Affect Growth, Flowering, and Postharvest Quality of Easter Lilies

The role of light quality on growth, flowering, and postharvest characteristics of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) was evaluated in two growing seasons using 4% CuSO4 and water (control) as spectral filters. The CuSO4 filter significantly reduced plant height and internode length. However, the height reduction was smaller in the 1994-95 season (9%) than in the 1995-96 growing season (32%). The number of days to flower bud appearance and flower opening, and the number and diameter of flowers were not significantly affected by the spectral filters in either season. The CuSO4 filters reduced flower longevity by 3 days in nonstored plants, and by 5 days when plants were subjected to 1 week storage at 4 °C prior to placing in the postharvest room. Results suggest that spectral filters are effective in controlling height and producing compact Easter lily plants without causing a delay in flowering or reducing number of flowers per plant but flower longevity can be adversely affected.

Spectral Filters Affect Growth, Flowering, and Postharvest Quality of Easter Lilies

The role of light quality on growth, flowering, and postharvest characteristics of `Nellie White' Easter lilies (Lilium longiflorum Thunb.) was evaluated in two growing seasons using 4% CuSO4 and water (control) as spectral filters. The CuSO4 filter significantly reduced plant height and internode length. However, the height reduction was smaller in the 1994—95 season (9%) than in the 1995—96 growing season (32%). The number of days to flower bud appearance and flower opening, and the number and diameter of flowers were not significantly affected by the spectral filters in either season. The CuSO4 filters reduced flower longevity by 3 days in nonstored plants, and by 5 days when plants were subjected to 1 week storage at 4 °C prior to placing in the postharvest room. Results suggest that spectral filters are effective in controlling height and producing compact Easter lily plants without causing a delay in flowering or reducing number of flowers per plant but flower longevity can be adversely affected.

Organ‐specific localization and molecular properties of three soluble invertases from Lilium longiflorum flower buds

Three soluble invertase (EC 3.2.1.26) isoforms from Easter lily (Lilium longiflorum Thunb. cv. Nellie White) flower buds were purified to apparent homogeneity. Non‐denaturing PAGE showed one band for all three invertases that corresponded to the invertase activity. SDS‐PAGE of purified invertase I gave a single band at 78 kDa, whereas invertases II and III gave three bands at 54, 52 and 24 kDa. Antibodies against tomato fruit acid invertase and Urtica dioica leaf acid invertase recognized all three invertase isoforms, whereas antibodies against wheat coleoptile acid invertase recognized only 56‐ and 54‐kDa bands of invertases II and III. Antibodies against wheat coleoptile invertase recognized the 54‐ and 52‐kDa proteins from crude extracts of all flower organs, and a 72‐kDa protein in both leaf and bulb scale extracts. All three invertases bound to Con‐A peroxidase. Deglycosylation of invertase I with glycopeptidase F was complete and resulted in a peptide of 75 kDa. Invertases II and III were deglycosylated partially by glycopeptidase F and resulted in proteins of 53, 51, 50 and 22 kDa. Invertase I was localized only in anther and filament, whereas the other two isoforms were present in all flower organs.

Sucrose‐cleaving enzymes and carbohydrate pools in Lilium longiflorum floral organs

The activities of soluble invertase (EC 3.2.1.26), cell wall invertase (EC 3.2.1.26) and sucrose synthase (EC 2.4.1.13) were determined in Easter lily (Lilium longiflorum Thunb. cv. Nellie White) floral organs during flower development. These enzyme activities were correlated with dry weight gains and carbohydrate pools to investigate the importance of their expression in maintaining sink strength of floral organs. In the early stages of flower bud development, anthers exhibited the highest rates of dry weight gain and activity of sucrolytic enzymes. Once anther growth was completed, the dry weight gain of tepal, filament, stigma and style increased with a concomitant increase in hexose concentrations and invertase activity. Although all three enzymes capable of catalyzing sucrose cleavage were present in every flower organ of L. longiflorum, soluble invertase was the predominant enzyme in all flower organs except stigma where cell wall invertase dominated. Soluble invertase activity was highly correlated with dry weight gain in most of the flower organs.