Search Results
Grapevines rely on arbuscular mycorrhizal fungi (AMF) to obtain ample phosphorus (P) from soils with low to moderate P like the Ultisols of western Oregon. Prior research indicated that nine species, or virtual taxa, of AMF colonized the roots of ‘Pinot noir’ at greater than 1% abundance in a single vineyard. However, little is known about how different taxa within a community vary in their capacity to function as symbionts with grapevines. The effectiveness of five native AMF species representing five genera to promote growth and nutrient uptake of ‘Pinot noir’ was examined in a fumigated Ultisol soil under well-watered and periodically dry conditions. Plants were grown with each of the different isolates alone or without AMF. After 8 and 16 weeks, whole vines were destructively harvested and biomass and nutrients were determined. Results showed that four of the isolates colonized roots extensively, increased root and shoot biomass, and predominantly increased P uptake. A Claroideoglomus isolate was superior in promoting shoot growth as compared with Rhizophagus irregularis, even though both isolates increased P uptake to the same extent, suggesting a higher carbon cost for R. irregularis. Scutellospora calospora failed to colonize roots beyond a trace and had no impact on vine performance. The ability to increase P uptake among the four effective fungi was not related to the frequency of arbuscules in roots suggesting that some P exchange occurs via hyphae within the cortex, particularly for Funneliformis mosseae. Water limitation reduced P uptake as a main effect across all mycorrhizal treatments, suggesting that the native isolates studied here have similar functionality under well-watered and periodically dry conditions.
In vitro testing was conducted to evaluate the inhibition potential of three compost teas (pine bark, manure, and vermicasting), Root Rescue Landscape Powder® (a mix of mycorrhizae and other beneficial microbes), waste diatomaceous earth (DE; from beer brewing), and a greenhouse nutrient solution, which had been reused for 20 years on six plant pathogens: Fusarium foetens, Rhizoctonia solani, Sclerotinia sclerotiorum, Phytophthora cryptogea, Pythium intermedium, and P. ultimum. The test materials showed in vitro inhibition on most of the test pathogens. Pine bark tea suppressed growth of all six pathogens, and inhibition exceeded 50% after 10 days of coincubation. Vermicasting tea showed over 40% inhibition against S. sclerotiorum and F. foetens; manure tea showed 42% inhibition against F. foetens; DE showed 40% inhibition against F. foetens, S. sclerotiorum, and R. solani; whereas reused greenhouse nutrient solution showed 56.7% inhibition against R. solani and 43.4% inhibition against F. foetens; Root Rescue showed 66% inhibition against P. intermedium. The results suggest that the six test materials have potential in the control of these soil- and water-borne pathogens in plant production system.
Leaf segments of greenhouse-grown Ulmus americana L. plants cultured on a Murashige and Skoog basal salts medium supplemented with 0.22 mg/L thidiazuron formed friable type of callus and regenerated shoots. This friable callus readily formed a cell suspension when the callus was placed in a liquid MS medium containing 2 mg/L 1-naphthaleneacetic acid and 1 mg/L 6-benzylaminopurine. Shoots were regenerated from 3-month-old suspension cell cultures after the suspension cells had been cultured on solid medium. Shoots developed roots on MS medium containing 0.1 mg/L indole-3-butyric acid. Intact plants were successfully established in soil.
The development of scoreable genetic markers in poinsettia will be valuable for cultivar identification and for use in patent protection. In this study, polymerase chain reaction (PCR) and randomly amplified polymorphic DNA (RAPD) techniques were investigated for their feasibility in the identification of poinsettia cultivars. DNA was extracted from leaf tissues using the CTAB method. Thirty-six out of 39 (92.4%) primers amplified poinsettia DNA. The size of the amplified DNA fragments ranged from 140 to 2,000 base pairs. On average, 5.4 bands (range 1 - 13) were obtained per primer. A total of 195 bands were obtained; 49 (25.1%) bands were polymorphic in the 9 tested poinsettia cultivars. All tested cultivars could be discriminated with the banding profiles generated from 2 primers. RADP markers provide a consistently reliable and efficient technique for the identification of poinsettia cultivar.
Randomly amplified polymorphic DNA (RAPD) techniques were used to compare the DNA from leaf tissues of nine commercial poinsettia (Euphorbia pulcherrima Wild ex Klotzsch) cultivars. Amplification occurred in 57 out of 60 (95%) tested primers. Nine primers that revealed polymorphisms among cultivars were selected for further evaluation. Forty-eight RAPD bands were scored from these primers, and 33 (69%) were polymorphic. All tested cultivars could be discriminated with seven bands generated from primers OPB7 and OPC13. Results of a UPGMA cluster analysis and principal components analysis placed the nine cultivars into two groups: one group consisted of `Jingle Bells', `Supjibi', and `V-17 Angelika', the other of `V-14 Glory', `Red Sails', `Jolly Red', and `Freedom'. `Lilo Red' and `Pink Peppermint' belonged to the latter group, but were relatively distant from other cultivars in that group. These results indicate that RAPDs are efficient for identification of poinsettia cultivars and for determination of the genetic relationships among cultivars.
High- and low-affinity transport systems are the main pathways for the transportation of NO3 – and NH4 + across intracellular membranes. NO3 − and NH4 + are assimilated through different metabolic pathways in plants. Fifteen ATP molecules are hydrolyzed in the metabolic process of NO3 –; however, only five ATP molecules are hydrolyzed in that of NH4 +. In this research, seedlings of Iris pseudacorus and Iris japonica were used as the experimental materials in the NO3 –:NH4 + = 30:0, NO3 –:NH4 + = 28:2, NO3 –:NH4 + = 27:3, NO3 –:NH4 + = 15:15, NO3 –:NH4 + = 3:27, and NO3 –:NH4 + = 0:30 treatments at the 7.5 mmol·L−1 the total nitrogen content (TN). The intracellular free energy was represented by physiological resistance (R) and physiological impedance (Z) according to the Nernst equation and could conveniently and comprehensively determine the cellular metabolic energy (GB). The maximum absorption rate (Vmax) and Michaelis constant (Km) for NH4 + and NO3 – uptake were calculated according to the kinetic equation. The results showed that the cellular metabolic energy (GB) of I. pseudacorus was 1 to 1.5 times lower than that of I. japonica at each treatment on the 10th day. The GB values of I. pseudacorus and I. japonica seedlings increased with increasing NH4 + concentration. However, there was a turning point at the NO3 –:NH4 + = 15:15 treatment for the cellular metabolic energy of I. pseudacorus and I. japonica. Correlation analysis showed that the value of cellular metabolic energy was negatively correlated with the Vmax and Km for NO3 – uptake, whereas it was positively correlated with that for NH4 + uptake. These results demonstrate that the NO3 –:NH4 + = 27:3 treatment level was the most suitable for I. pseudacorus and I. japonica. This indicates that the greater cellular metabolic energy is the most suitable for plant growth when the concentration of ammonium or nitrate had no significant difference at treatment. These results provide a simple and rapid solution for removal of nitrogen by determination of cellular metabolic energy.
Protoplasts were isolated from embryogenic calli of Citrus reticulata cv. Ponkan and Citropsis gabunensis, and fused in electric fields. The maximal fusion efficiency was obtained by application of AC at 75 V/cm (1.0 MHz) and DC square-wave pulse at 1.125 KV/cm for 40 usec. Fusion-treated protoplasts were cultured on MT medium without phytohormone, solidified with 0.6% agar. Colonies from the protoplasts were proliferated on MT medium with zeatin 1 mg/l and 0.9% agar. Selection of somatic hybrid callus was based on chromosome count and isoenzyme analysis. The somatic hybrids were tetraploid (2n=36). C. reticulata and C. gabunensis were both homozygous at Got-1 locus, but distinguishable easily because band of the latter migrated faster than that of the former. In zymogram of somatic hybrid, both parent bands were retained and a new hybrid band was also evident between them. Embryos from somatic-hybrid callus regenerated intact plant. The hybrid plants showed intermediate morphological characteristics of the parents.
The genus of Hosta (plantain lily) is a shade-loving herbaceous plant with attractive foliage. Confusion exists in the genus regarding nomenclature and taxonomy. In this study, the possibility of application of RAPD markers to characterize Hosta species and cultivars was investigated. DNA was extracted from 28 Hosta species and cultivars. Thirty-six of 37 primers generated RAPD markers. Phylogenic analysis and principal components analysis showed groupings among cultivars. Results indicated that H. plantaginea and H. ventricosa were the most distant from the other tested species and cultivars. These results suggest RAPDs may be useful in the identification and analysis of relationships among Hosta.
The lengthy generation times associated with woody ornamentals has led to the exploration of alternatives to traditional breeding methods for the development of new cultivars. This report summarizes the results of experiments designed to examine the feasibility of altering plant morphology by DNA assimilation following electroporation of intact seedlings. Brassica rapa (a nonwoody plant) was chosen as a model plant for initial experiments due to its rapid development and short generation time. Seedlings were subjected to either one or five 300-V pulses (99 ms) in the presence or absence of foreign DNA. Foreign DNA used was Ulmus parvarvifolia at a concentration of 200 μg·mL–1. Results indicate a lower survival rate of seedlings electoporated in the presence of DNA. Data were recorded after 21 days for plant height and leaf number. No significant differences were noted for plant height. However, significantly more leaves were produced on plants electroporated (five pulses) in the presence of foreign DNA. These results suggest the possible utilization of this technique for induction of variation in other plants.