Ilex Crenata Research Articles

Photosynthesis and Root Respiration in Ilex crenata `Rotundifolia' at Supraoptimal Root-zone Temperatures

Rooted stem cuttings of Ilex crenata Thunb. `Rotundifolia' were grown in a controlled-environment growth chamber. Root-zone temperatures were controlled with an electric system. Shoot carbon exchange and root respiration rates were determined in response to root-zone temperatures of 28, 32, 36, and 40C for 6 hour·day–1 for 7 days. Photosynthesis was decreased by root zones ≥ 32C, while root respiration increased with increasing root-zone temperature. Decreased photosynthetic rates were not due to increased stomatal resistance.

Root Respiratory Characteristics of `Rotundifolia' Holly under Supraoptimal Temperatures

Respiration of excised Ilex crenata (Thunb.) `Rotundifolia' roots as influenced by root-zone growth temperature and buffer solution temperature was measured in the presence and absence of salicylhydroxamic acid (SHAM) and potassium cyanide (KCN). Respiration rates of roots excised from plants grown for 3 weeks with root-zones at 30, 34, 38, or 42C decreased linearly with increased root-zone growth temperatures when the buffer solution was maintained at 25C. When the buffer solution was the same temperature as the root growth temperature, respiration rates were similar. Respiration in roots from plants grown with the root zone at 30C was maximal with the buffer solution at 34C and decreased to a minimum at 46C. Above 46C, a presumably extra-mitochondrial stimulation of O2 consumption occurred. The activity of the CN-resistant pathway was fully engaged (P' = 0.99) when roots were grown at 30C and buffer solution was at 25C (30-25). CN-resistant pathway activity decreased with `the buffer solution at 46C.

Herbicide Use In Propagation: Effects on Rooting and Root Growth of Stem Cuttings

Abstract Two experiments were conducted to determine the effects of several preemergence applied herbicides on rooting, root quality and subsequent root growth of selected woody cuttings. In the first experiment Ilex × attenuata Ashe ‘Fosteri’ rooting percentage, primary root numbers and root ratings were suppressed with Surflan (oryzalin). In the second experiment, the long-term effects of herbicide use in propagation were monitored for 13 months after potting. Suppression of one or more rooting variables occurred with the 3 species, Abelia X grandiflora ‘Sherwoodii’, Buxus microphylla var. koreana, and Ilex crenata ‘Compacta’, 8 weeks after cuttings were placed in propagation. Thirteen months later, Surflan treated boxwood exhibited root and shoot growth suppression while ‘Compacta’ holly exhibited suppressed root growth.

Tolerance of Woody Nursery Stock to Classic (chlorimuron) and Harmony (thiameturon)

Abstract Classic and Harmony applied at rates ranging from 0.009 kg ai/ha (0.008 lb ai/A) to 0.067 kg/ha (0.06 lb/A) provided excellent preemergence and postemergence control of common groundsel (Senecio vulgaris L.) 5 weeks after application to container-grown nursery plants. Classic at 0.034 kg/ha (0.03 lb/A) and 0.067 kg/ha (0.06 lb/A) reduced yellow nutsedge (Cyperus esculentus L.) growth by 50 to 77% 5 weeks after preemergence or postemergence treatments. Harmony did not affect yellow nutsedge from either type of application. ‘Seagreen’ juniper (Juniperus chinensis L.), ‘Blue Pacific’ juniper (Juniperus conferta Parl.) and ‘Bennetts Compacta’ holly (Ilex crenata Thunb.) tolerated all rates of Classic and Harmony. ‘Girard's Rose’ (Rhododendron kaempferi Planch.) and ‘Coral Bells’ azale(Rhododendron obtusum (Lindl.) Planch.), and redtip photinia (Photinia × Fraseri Dress) were initially injured by these herbicides, but outgrew the foliar damage.

Preparation of Charcoal Flowers

Charcoal flowers had been used at tea ceremony in Edo era in Japan by the name of “Ohanazumi”, but they remained in the literature only its name without any description on their preparation method. In the present study a preparation of charcoal flowers was tried by the application of pre-oxidation process. Flowers were dried at first and then oxidized in a furnace or in an air oven at temperatures between 200°C and 300°C. The flowers thus oxidized were put into a quartz vessel and carbonized by heating in a crucible furnace from 250°Cd to 600°C in a flow of argon gas with a heating rate of 120°C/hr. The charcoal flowers could easily be prepared by this method in a short time of four hours or so. The charcoal flowers obtained in the present study were those from chrysanthemum, babies-breath, sazanka, fuyou (a kind of rose mallow) and etc. Art charcoals from leaves of Japanese holly and ginkgo, mandarin oranges and dried mushrooms (Shiitake) were also made.

Overwintering Container-grown Nursery Crops: Plant, Air and Medium Thermal Response to Porous Row Covers

Abstract Three structureless row covers (white, spunbonded polyester and two weights of white, spunbonded polypropylene) were evaluated for winter protection of container grown ‘Helleri’ holly (Ilex crenata ‘Helleri’), ‘Atropurpurea Nana’ nandina (Nandina domestica ‘Atropurpurea Nana’), Fraser photinia (Photinia × fraseri), and ‘Mohave’ pyracantha (Pyracantha Koidzumii × coccinea ‘Mohave’) relative to white copolymer film and white copolymer backed thermoblanket over quonset-shaped structures and an unprotected control. Air and rooting medium temperatures were monitored during the deployment period. Visual foliar injury ratings were taken immediately after treatments were removed and again four months later. Visual shoot injury ratings were correlated with the mean daily average and the mean daily minimum temperature of air and rooting medium within each treatment. Both polypropylene covers provided protection for plants in the interior of a consolidated group equivalent to white poly and the thermoblanket for all species except Pyracantha. Porous row covers are a feasible alternative to standard protection systems.

Plant Response to Container Planting Method and Media

Abstract Shoot dry weight and relative root density of Ilex crenata Thunb. ‘Compacta’ and Rhododendron obtusum (Lindl.) Planch. ‘Hino Crimson’ were greater when liners were transplanted into holes with a core removed (excavated) compared to holes formed by compression (dibbled). Growth index, relative root density, and shoot dry weight increased as the percent pine bark in the growth media increased from 50% to 80 or 90% pine bark with holly and from 50% to 90% pine bark with azalea. Bulk density decreased and air porosity and irrigation frequency increased as the percent pine bark in pine bark:sandy loam container media increased from 50% to 100%. In a second experiment, root density and shoot dry weight of Ilex crenata Thunb. ‘Helleri’, but not Rhododendron × ‘Trouper’, were greater in pine bark and pine bark-sandy loam media when the planting hole was excavated rather than dibbled. Plant growth of the 2 species in peat-based media was not influenced by planting method.

14Carbon-labeled Photosynthate Partitioning in Ilex crenata `Rotundifolia' at Supraoptimal Root-zone Temperatures

Ilex crenata Thunb. `Rotundifolia' split-root plants were grown for 3 weeks with root zones at 30/30, 30/34, 30/38, 30/42, 34/34, 38/38, and 42/42C. The 38C root-zone treatment was the upper threshold for several growth and physiological characteristics. A portion of the root system grown at or near the optimum temperature could compensate, in terms of shoot growth, for part of the root system exposed to supraoptimal root-zone temperatures up to 38C. Higher root-zone temperatures did not affect short-term photosynthetic rates or root : shoot ratios, but altered photosynthate partitioning to various stem and root sinks. Although no differences were found for total 14C partitioned to the roots, partitioning of 14C into soluble and insoluble fractions and the magnitude of root respiration and exudation were influenced by treatment. Heating half of a root system at 38C increased the amount of 14C respired from the heated side and increased the total CO2respired from the nonheated (30C) half. Exposure of both root halves to 42C resulted in membrane damage that increased the loss of 14C-labeled photosynthates through leakage into the medium.

TIMING OF OSMOCOTE REAPPLICATION ON GROWTH OF CONTAINERIZED `HELLERI' HOLLY.

Ilex crenata `Helleri' rooted cuttings were container grown for one summer with Osmocote 18N-2.6P-7.6K which was reapplied at different times. Beginning in April and every month thereafter until October, five plants were harvested and separated into roots and shoots for dry weight and nitrogen (N) analysis. Plants that had received a reapplication of Osmocote in June or July were larger in October than those that received no supplemental fertilizer. If reapplication occurred in August or September, no influence on growth was realized. Plants that were not supplemented had lower percent tissue and medium solution N. These data demonstrate that tissue nutrient analysis as well as the medium nutrient levels extracted with the pour-through procedure can be used to determine when reapplication of a slow-release fertilizer is necessary to promote optimal growth.

EFFECT OF SUPRAOPTIMAL TEMPERATURES ON ROOT RESPIRATORY CHARACTERISTICS OF `ROTUNDIFOLIA' HOLLY

Respiration of excised Ilex crenata `Rotundifolia' roots as influenced by root-zone growth temperature and buffer solution temperature was measured in the presence and absence of SHAM and KCN. Respiration rates of roots excised from plants grown for three weeks at root-zone temperatures of 30, 34, 38, and 42 C decreased linearly as root-zone temperature increased when the buffer solution was maintained at 25 C. When the buffer solution temperature was the same as the root growth temperature, no differences in respiration rate were found. When plants were grown at a root-zone temperature of 30 C, respiration was maximal at 34 C and decreased to a minimum at 46 C. Above 46 C, stimulation of O2 consumption occurred which was presumed to be extra-mitochondrial. CN-resistant pathway activity decreased at a buffer solution temperature of 46 C which was similar to the critical threshold temperature (48±1.5 C) for `Rotundifolia' holly roots.

Influence of Winter Protection Covers on Survival and Hardiness of Container Grown Ilex crenata Thunb. ‘Green Island’ and Euonymus fortunei (Turcz.) ‘Emerald 'n Gold’

Abstract Five systems for protection of container grown nursery stock were compared for freeze injury to shoots and roots of Ilex crenata Thunb. ‘Green Island’ and Euonymus fortunei (Turcz.) ‘Emerald 'n Gold’. In three treatments, plants were protected starting November 15, 1988 either in a white co-polymer house or with structureless non-woven polypropylene covers (N-Sulate™ or Typar™). In a fourth treatment, structureless clear polyethylene was applied when temperatures were cold enough (−7°C (25°F) to cause injury. The controls were not covered. The white co-polymer house and the temporary covering with clear polyethylene reduced the number of hours below −7°C (25°F) in the canopy or medium and resulted in fewer plant losses compared to the nonwoven covers or the controls. Development of shoot and root hardiness of both species was monitored prior to and after the low temperature period. Roots of plants under long-term protective covers were slightly less hardy than those not covered.

THE INFLUENCE OF SUPRAOPTIMAL ROOT-ZONE TEMPERATURES ON 14C PHOTOSYNTHATE PARTITIONING IN ILEX CRENATA THUNB. `ROTUNDIFOLIA'

Ilex crenata Thunb. `Rotundifolia' split-root plants were grown for 3 weeks at root-zone temperatures of 30/30, 30/34, 30/38, 30/42, 34/34, 38/38 and 42/42. The 38 C root-zone temperature treatment was the upper threshold for a number of growth and physiological parameters. A portion of the root system grown at near optimum temperatures could compensate in terms of shoot growth for part of the root system exposed to supraoptimal root-zone temperatures up to the 38 C critical threshold. Higher root-zone temperatures did not affect photosynthetic rates or root:shoot ratios, but altered photosynthate partitioning to different stem and root sinks. Although no differences were found for total 14C partitioned to the roots, partitioning of the 14C into soluble and insoluble fractions and the magnitude of root respiration and exudation were influenced by treatment. Heating half of a root system at 38 C increased the amount of 14C respired from the heated side and increased the total CO2 respired from the non-heated (30 C) half. Exposure of both root halves to 42 C resulted in membrane damage which increased the leakage of 14C photosynthates into the medium.

Effect of Trickle Irrigation, Nitrogen Rate, and Method of Application on Field-grown ‘Compacta’ Japanese Holly

Abstract Three methods of N application and 4 N rates of 34, 67, 134, and 268 kg/ha (30,60 120, and 240 lbs/A) were evaluated on field-grown ‘Compacta’ Japanese holly (Ilex crenata Thunb. ‘Compacta’). Fertilizer application methods consisted of NH4NO3 broadcast over trickle irrigated and non-irrigated plants, and injection of NH4NO3 through the trickle irrigation system. Irrigation regardless of whether N was surface applied or injected through the system, increased root and shoot dry weights, plant size, visual ratings, and percent survival. Irrigated plants had a more fibrous root system. N rate had no affect on root or shoot dry weights, root distribution, visual ratings, or percent survival.

Influence of Metolachlor on Ilex crenata Thunb. for Control of Yellow Nutsedge

Abstract A single spring or fall application of Dual 8E (metolachlor) at 13.5 kg/ha (12.0 lb/A) to newly planted ‘Hetzii’ and ‘Howardi’ Japanese holly caused 15 to 18% injury during the first few weeks after treatment. No additional injury or reduced growth was evident with any Dual treatments 4 weeks after application. Applications of Dual at rates up to 13.5 kg/ha (12.0 lb/A) to established ‘Hetzii’ holly did not cause injury or affect plant height × width. Dual at 4.5 kg/ha (4.0 lb/A) to 13.5 kg/ha (12.0 lb/A) was adequate to control yellow nutsedge (Cyperus esculentus L.).

Chemically Induced Branching of Woody Landscape Plants

Abstract Axillary budbreak of Ilex Crenata Thunb. ‘Helleri’ and ‘Ilex vomitoria’ Ait. ‘Stoke's Dwarf’ hollies was promoted by a single BA (N-(phenylmethyl)-1H-purin-6-amine) application of 125–1000 ppm compared to an unpruned control. Budbreak of Photinia × Fraseri Dress was stimulated by 500–2500 ppm BA and 2000–5000 ppm Promalin (BA + GA4+7). Budbreak in Nandina domestica Thunb. ‘Harbour Dwarf’ increased with 1000–2500 ppm BA and 2000–5000 ppm Promalin application. Budbreak of Rhododendron × ‘Formosa’ azalea was promoted by 2000 and 2500 ppm BA and 2000–5000 ppm Promalin. Axillary budbreak of Ternstroemia gymnanthera (Wight & Arn.) T. Sprague) and Raphiolepis indica (L.) Lindl. was not affected by BA or Promalin application.

Water Use and Average Growth Index of Five Species of Container Grown Woody Landscape Plants

Abstract Liners of Juniperus horizontalis Moench ‘Wiltonii’, Ilex crenata Thunb. ‘Rotundifolia’, Rhododendron × L. ‘Hershey's Red’, Pyracantha × M.J. Roem ‘Teton’, and Photinia × fraseri Dress were grown to saleable size in 3.1 1 (1 gal) containers. Plant water consumption was measured during 336 days from June 24, 1986, to June 19, 1987. Pyracantha consumed the most water (50.4 1 (13.3 gal)/plant) while photinia consumed the least water (37.8 1 (10.0 gal)/plant). Based on the increase in growth index per liter of water consumed, photinia used water most efficiently. Growth index, pan evaporation, or growth index and pan evaporation were the best predictors of plant water use.

Winter Protection of Container-grown Woody Ornamentals in Zone 9a

Abstract Four methods of overwintering container-grown ornamental nursery stock were evaluated. Canopy temperatures of plants unprotected or covered with a thin layer of ice closely followed air temperatures during subfreezing conditions; minimum ambient air temperature was – 16C. Canopy temperatures under white copolymer film fluctuated widely, while canopy and growth medium temperatures of plants continuously irrigated during subfreezing temperatures did not drop below 0C. Root injury of all species and foliar injury of azalea (Rhododendron × ‘Due de Rohan’), euonymus (Euonymus japonica Thunb. ‘Microphylla’ H. Jaeg.), and pittosporum [Pittosporum tobira (Thunb.) Ait.] were least when plants were continuously irrigated or covered with white copolymer film. Foliage of Japanese holly (Ilex crenata Thunb. ‘Compacta’) and dwarf Burford holly (Ilex cornuta Lindl & Paxt. ‘Burfordii Nana’) was not injured with any treatment. Bark splitting of azaleas was most severe under the thinly iced and white copolymer-covered treatments, less severe in the unprotected treatment, and least with continuous irrigation.

Control of Prostrate Spurge (Euphorbia humistrata) and Large Crabgrass (Digitaria sanquinalas) in Container Grown Ilex crenata ‘Compacta’ With Herbicide Combinations

Abstract Granular herbicide combinations were evaluated for longevity of prostrate spurge (Euphorbia humistrata Engelm.ex.Gray) and large crabgrass (Digitaria sanguinalis L.) control. Rout (oxytluorfen + oryzalin), Ornamental Herbicide 2 (oxytluorfen + pendimethalin), Ronstar plus Modown (oxadiazon + bifenox) and Ronstar (oxadiazon) were applied at labeled rates and twice labeled rate in container grown Compact Japanese Holly (Ilex crenata ‘Compacta’). Weeds were reseeded each month but herbicides were not reapplied. The normal use rate controlled both weeds during the first 30 days after treatment (DAT) while twice this rate controlled the weed species at 60 DAT. No herbicide treatment effectively (>80%) controlled prostrate spurge 90 DAT. The high rate of Rout controlled (>80%) crabgrass at 90 DAT. Weed numbers and above ground biomass retlected visual control ratings. Compact Japanese Holly was not injured by any treatment.

Pretransplant Application of Goal (Oxyfluorfen) for Weed Control in Container-grown Nursery Crops

Abstract No injury was observed to ‘Hershey Red’, ‘Pleasant White’ and ‘Scarlet Rose’ azalea (Rhododendron obtusum Planch.) ‘Prince of Wales’ juniper (Juniperus horizontalis Moench), ‘Helleri’ holly (Ilex crenata Thunb.) or ‘Green beauty’ boxwood (Buxus microphylla Siebold & Zucc.) following pretransplant applications of Goal (oxyfluorfen) at rates ranging from 0.6 to 4.5 kg ai/ha (0.5 to 4.0 lb/A). Acceptable control of common groundsel (Senecio vulgaris L.) (less than one weed per pot) lasted approximately 1 month at 0.6 kg/ha (0.5 lb/A), 2 to 3 months at 1.1 kg/ha (1.0 lb/A), 3 to 4 months at 2.2 kg/ha (2.0 lb/A) and 4 months at 4.5 kg/ha (4.0 lb/A) with sprayed applications of Goal. Sprayed applications of Goal at 1.1 kg/ha (1.0 lb/A) gave equivalent weed control to a post-transplant application of Ornamental Herbicide 2, a granular formulation containing 2% oxyfluorfen and 1% pendimethalin, at 3.3 kg ai/ha (3.0 lb ai/A).

花粉分析による復元植生の広がり 駒止大谷地湿原（福島県）の例

Three pollen diagrams of Komado-Ohyachi Moor in Fukushima Prefecture were compared. Data for the same period (from the climatic optimum in the Holocene to the present) were available from the three sites, which indicated that Fagus crenata forest was predominant over the whole Komado area, and at the same time one site (K12) was dominated by a Quercus mongolica var. grosseserrata stand and the other (JIMBO and SHIODA, 1980) was dominated by a Pinus parviflora var. pentaphylla stand. The former was referred to as“regional”vegetation and the latter two as“local”vegetations. Pollen analysis showed that Site K12 began as a community dominated by Cyperaceae in the latest Pleistocene and changed into a Moliniopsis japonica-Sphagnum community, a Fraxinus mandshurica var. japonica forest, a Osmundastrum cinnamomeum var. fokiense community, a Ilex crenata scrub, a Moliniopsis japonica-Osmundastrum cinnamomeum var. fokiense community and a Moliniopsis japonica-Cyperaceae community, in that order.