A greenhouse solution culture experiment was conducted to study the interactions of Ca, K and Mn supply on the concentration of 7 elements in bark tissues of ‘Delicious’ apple (Malus domestica Borkh) trees as related to internal bark necrosis (IBN). Under a regime of low Ca and high Mn, IBN symptoms developed late in the second growing season on the scion barks but not on the rootstock bark. Both the degree of severity and the incidence of the disorder increased with increasing K levels. Low Ca and high Mn concentrations in the barks are apparently necessary for the development of IBN, and under these conditions K affects the degree of severity. It is suggested that the higher K concentrations enhanced Mn toxicity by lowering the threshold for Mn-induced IBN, while Ca responded as a detoxifying agent. Low concentrations of B and P may contribute to IBN development, while Mg and Fe were not related to symptom development.
Shiitake mushrooms contain lentinan, a polysaccharide that has numerous medicinal benefits. The objective of this research was to determine the impact of various rates of chipped and sawmill bark added to the substrate on lentinan found in shiitake mushrooms. Crude polysaccharide extract (CPE) and lentinan (LTN) content was significantly different among shiitake mushrooms grown on various artificial substrates containing different percentages of sawdust and chipped bark. The addition of chipped bark content from 0% to 50% increased the CPE content, but an increase in chipped bark content from 50% to 100% decreased the CPE and LTN content. CPE content in mushrooms was greater when equal proportions of sawdust and bark were used. A 100% heartwood treatment had the least CPE content.
Total N content in the shoots of Chrysanthemum morifolium Ramat ‘Bright Golden Anne’ grown in hardwood bark was significantly greater when utilizing (NH4)2SO4 source of N than with KNO3 source. The NH4 + concn in the shoots was greatest at the low pH range when (NH4)2SO4 was the source of N. The NH4 + concn in the media was greatest at the low pH range when utilizing the (NH4)2SO4 and NH4NO3 sources of N.
The greatest dry wt of shoots was obtained if test plants were treated with both NH4 + and NO3 − forms of N with NH4NO3 source of N at the higher pH range and without the nitrification inhibitor.
Bulk density (BD) of potting media increased as the percentage of sand was increased in the medium. Because of the “fitting” together of particles, volume of medium mixtures was always less than the total volume of the separate components. Particle size distribution was determined most accurately on a volume basis and was used to identify the potting mixtures. The percentage of medium components (bark or sand) retained on any given sieve size could be determined from BD data. Percolation rate, and cation exchange capacity (CEC) declined as the percentage of sand was increased in the potting mixture. CEC was most accurately determined on a volume basis. Increasing the percentage of sand in the potting medium raised pH from 4.1 to 5.4.
A significant pest affecting commonly planted Betula spp. is the birch leafminer (Fenusa pusilla Lepeletier), an insect that can be present in large populations in the landscape and can greatly reduce the vigor and ornamental value of these trees. Twenty-two interspecific crosses were performed between leafminer resistant and susceptible Betula species in an attempt to create the novel combination of ornamental white bark and significant leafminer resistance. Of the nine successful crosses, two produced resistant offspring. Progeny of the diploid × hexaploid cross B. turkestanica Litvin (2x) × B. alleghaniensis Britt. (6x) displayed a broad range of resistance levels, likely the result of segregating alleles contributed by the hexaploid parent. All crosses involving highly resistant individuals of B. costata Trautv. (2x) yielded leafminer susceptible progeny. These results suggest that the larval antibiosis demonstrated by B. alleghaniensis and B. costata is inherited as a recessive trait, and exhibits a gene dosage effect as evidenced by the B. turkestanica × B. alleghaniensis offspring. While most progeny of the B. populifolia Marsh (2x) × B. maximowicziana Regal (2x) cross were susceptible, a single resistant offspring, which was found to be triploid (3x), displayed a mechanism of resistance similar to that of a hypersensitive response. No strong intersectional barriers to hybridization were observed and all interploidy crosses were successful. The chromosome numbers of B. costata (2n = 2x = 28) and B. turkestanica (2n = 2x = 28) are reported here for the first time. The results of this study indicate that the potential exists for the development of insect resistant, ornamental white-barked birch clones through the implementation of a planned, systematic breeding program.
Rhizoctonia and Pythium crown and root rot of Euphorbia pulcherrima willd ex Kotzch cv. Annette Hegg Dark Red were suppressed in a composted hardwood bark medium amended with sphagnum peat. The suppression equalled that obtained in an aerated steam-treated peat medium drenched with fungicidies. Growth of ‘Annette Hegg Dark Red’ produced in the sphagnum peat-amended bark was improved over plants produced in a sterilized and fungicide drenched soil-peat-perlite medium. Addition of muck to composted hardwood bark negated the desirable growth effects.
Hardwood bark as a soil amendment for container-grown plants suppressed several species of parasitic nematodes in greenhouse tests. Volumetric bark to soil ratios of 4:1, 2:1, 1:1 and 1:2 greatly reduced incidence of root-knot caused by Meloidogyne hapla Chitwood and M. incognita (Kofoid and White) Chitwood on tomato (Lycopersicon esculentum Mill.). A 2:1 bark to soil mixture inhibited galling by M. incognita and population development of Pratylenchus penetrans (Cobb) Filipjev and Schuurmans Stekhoven and Trichodorus christiei Allen on Forsythia intermedia Zabel.
The physical and water-release characteristics of a gasifier residue in combination with bark, Canadian sphagnum peat, and sand were determined. Both gasifier residue and peat had characteristics more favorable for plant growth than bark or sand alone. The combination of gasifier residue and peat produced characteristics superior to gasifier residue or peat alone. Gasifier residue and combinations of gasifier residue and peat had almost twice the available water of a standard nursery medium. The addition of sand or bark decreased the performance of gasifier residue in a number of physical parameters. Unsieved gasifier residue had a particle size distribution suitable for container plant production.
Studies with herbaceous crops have indicated a similarity in the types of proteins that accumulate in response to environmental stresses and ABA. Many of these proteins belong to a group called dehydrins. We have identified a 60 kDa dehydrin-related protein (PCA 60) in peach associated with cold hardiness. Our objective was to determine if seasonal induction of dehydrins are a common feature in a wide array of woody plants Bark tissues from eight species of woody plants were collected monthly for 1.5 years. The species included: Prunus persica `Loring'; Malus domestica `Golden Delicious'; Rubus sp. `Chester'; Populus sp.; Salix babylonica; Cornus florida; Sassafras albidum, and Robinia Pseudo-acacia. Protein extraction, SDSPAGE, and immunoblotting were performed as previously reported. Immunoblots were probed with a polyclonal antibody recognizing a conserved region of dehydrin proteins (provided by Timothy Close). Although some proteins, immunologically related to dehydrins, appeared lo be constitutive, distinct seasonal patterns associated with winter acclimation were observed in all species. The molecular weights of these proteins varied, although there were similarities in related species (willow and poplar). Although this study represents a precursory examination of dehydrins, the results indicate that these proteins are common to woody plants and that further research to characterize their function is warranted.
Pine bark-filled containers periodically fertilized with NH4-N were heated from 21C to 28, 34, 40, 46, or 52C for daily exposures of 1, 2, 4, 6, or 24 hours over 20 days. Concentrations of NH4-N and NO3-N in medium solution extracts were determined every 5 days. Medium solution NH4-N concentration was higher at constant (24 hours) exposure to 40C than at lower temperatures or exposure times. There was a similar increase in NH4-N concentration for a 2-hour·day–1 exposure to 46C, with further increases in NH4-N for longer exposure times. By day 10, NH4-N concentration was highest after 1 hour·day–1 exposure to 52C. Decreases in medium solution NO3-N concentration generally coincided with the increases in NH4-N. These results indicate that container medium thermal periods, similar to those observed in nurseries of the southern United States, may inhibit nitrification, thereby influencing NH4-N: NO3-N ratios in the medium solution of plants fertilized with predominantly ammoniacal N sources.