Germination Rate of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] Seeds Affected by Their Orientation

Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seeds developwith the adaxial surface continuous with the cone scale. Onseparation, the scale side of the seed is lighter coloured andflatter than the side not previously in contact with the scale.Seeds oriented scale-side-up on a moist surface germinate morerapidly than seeds placed scale-side-down. When seeds were germinatedunder laboratory conditions, the response to orientation variedamong seeds of different geographic origin. Most of the geographicvariation in germination rate occurred when seeds were orientedscale-side-up. Pseudotsuga menziesii (Mirb.) Franco, Douglas-fir germination, orientation of seeds     

Growth Analysis of Perennial Plants: The Relative Production Rate and its Yield Components

A new formulation for plant growth analysis, called the relativeproduction rate, is proposed for use in the study of perennialplants. The new measure and its yield components are similarto current growth analysis, but use the annual increment ofgrowth, rather than total accumulated growth, as the basis forassessing performance. The relative production rate removesaccumulated past growth of the perennating structure, a majordeterminant of relative growth rate, and acts independentlyof tree size as a measure of the vigour of growth. The multiplicativeyield components of this relative production rate also providebetter insight into the current morphological and physiologicalfeatures of the tree than the standard growth analysis formulations.Examples are given using Douglas-fir (Pseudotsuga menziesii(Mirb.) Franco) and red pine (Pinus resinosa Ait.) plantationsto illustrate the methodology proposed. Pseudotsuga menziesii (Mirb.) Franco, Pinus resinosa Ait., Douglas-fir, red pine, growth analysis, relative production rate, tree development, competition     

A sex-averaged genetic linkage map in coastal Douglas-fir (Pseudotsuga menziesii[Mirb.] Franco var ‘menziesii’) based on RFLP and RAPD markers

 We have constructed a sex-averaged genetic linkage map in coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var ‘menziesii’) using a three-generation outcrossed pedigree and molecular markers. Our research objectives are to learn about genome organization and to identify markers associated with adaptive traits. The map reported here is comprised of 141 markers organized into 17 linkage groups and covers 1,062 centiMorgans (cM). Of the markers positioned on the map, 94 were derived from a Douglas-fir complimentary-DNA (cDNA) library that was constructed from new-growth needle tissue. Other markers include 11 Douglas-fir genomic-DNAs, 20 loblolly pine (Pinus taeda L.) cDNAs, 15 random amplified polymorphic DNAs (RAPDs) and a PCR-amplified phytochrome probe. A high degree of variation was detected in each of the two parents of our mapping population, and many of the restriction fragment length polymorphism (RFLP) and RAPD phenotypes were complex. Marker data were analyzed for linkage using mapping software JOINMAP version 2.0. Received: 16 March 1998 / Accepted: 22 April 1998     

Under-storey Nutrient Content in an Age Sequence of Douglas-fir Stands

The nutrient concentrations and contents of the under-storeyspecies were estimated for a series of Pacific North-west Douglas-fir[Pseudotsuga menxiessii (Mirb.) Franco] stands ranging in agefrom 9 to 95 years. Analyses were carried out for ash, N, P,K, Ca, Mg, Mn, Fe, Zn and Na and significant differences innutrient concentrations were found to exist between species;species rejecting certain nutrients and accumulating others.General trends for mean concentrations of some nutrients areassociated with stand maturity in that ash, K and Mg decline,P and Mn increase and N and Ca reaches a peak at 20–30years and then declines. The nutrient contents (kg ha^–1)of the under-storey component of the stands are presented andtrends discussed. Mineral nutrient content, under-storey vegetation, Pseudotsuga menziessii stands, Douglas-fir     

Persistent Effects of Short-term, High Exposure to Chlorine Gas on Physiology and Growth of Pinus ponderosa andPseudotsuga menziesii

Following a single acute exposure to chlorine gas, persistenteffects on epicuticular waxes, cuticular transpiration, treegrowth and mortality were studied in foliage of Pinus ponderosaand Pseudotsuga menziesii for three growing seasons. Chlorinegas exposure caused foliar injury to both exposed foliage andfoliage that flushed after exposure (P < 0.05). The tendencyto form films of water rather than droplets was greater in directlyexposed foliage (P < 0.001). Rates of cuticular transpirationwere higher for directly and indirectly exposed foliage of Pinusponderosa up to 1 year after exposure and up to 6 months afterexposure for directly exposed Pseudotsuga menziesii(P < 0.001),after which P. menziesii needles defoliated. Total water content(TWC) and relative water content were significantly correlatedwith foliar injury (P < 0.05). TWC was lower for directlyexposed foliage up to 1 year after exposure (P < 0.001).There was no persistent negative effect on F_v/F_m ratios after1 year. Exposure to chlorine gas did not affect needle lengthor annual shoot increment growth, but exposure was correlatedwith increased bud production. Needle longevity of foliage thatflushed 2 months after exposure was reduced significantly (P< 0.001). Annual stem increment growth for both species decreasedover at least three growing seasons following chlorine gas exposure(P < 0.001), and depended on distance from the spill site.Cone production was lower for exposed Pinus ponderosa treescompared to controls (P < 0.05), and tree mortality was higherwithin approx. 50 m of the release site forPseudotsuga menziesii. Growth responses for both conifers agreed well with predictedpatterns of carbon allocation after defoliation caused by chlorinegas exposure. Copyright 2001 Annals of Botany Company Pinus ponderosa, Pseudotsuga menziesii, conifers, chlorine gas, leaf wettability, cuticular transpiration, water relations, growth, mortality     

Vesicular mycorrhizal colonization of seedlings of Pinaceae and Betulaceae after spore inoculation with Glomus intraradices

 Although Pinaceae and Betulaceae have been reported to contain Glomus–type root endophytes, its ecological importance and the conditions influencing this symbiosis are poorly understood. Seedlings of Abies lasiocarpa, Alnus rubra, Pinus contorta, Pinus ponderosa, Pseudotsuga menziesii, and Tsuga heterophylla were inoculated with Glomus intraradices to determine the vesicular-arbuscular mycorrhizae (VAM) development and responsiveness of these hosts. The role of companion VAM host plants on mycorrhizal colonization and nutrient uptake by Pseudotsuga menziesii was also examined by growing seedlings of Pseudotsuga menziesii in dual culture with VAM hosts Thuja plicata or Calamagrostis rubescens. After 8 weeks, no seedlings were colonized. At 16 weeks, 8 of 17 Thuja plicata seedlings grown with Pseudotsuga menziesii and all 18 inoculated Thuja plicata seedlings grown alone were colonized with vesicles and hyphae. Two of 17 inoculated Pseudotsuga menziesii seedlings grown in dual culture with Thuja plicata were colonized with abundant vesicles and hyphae. No ectomycorrhizal seedlings grown in monoculture were colonized. At 9 months, all 10 Calamagrostis rubescens and all 10 inoculated Pseudotsuga menziesii seedlings grown in dual culture were colonized by vesicles and hyphae. Two of 10 inoculated Pseudotsuga menziesiiand 1 of 10 inoculated Pinus ponderosa seedlings grown in monoculture were similarly colonized. The mean phosphorus content in the needles of colonized Pseudotsuga menziesii seedlings grown with Calamagrostis rubescens was about twice as high as in noncolonized Pseudotsuga menziesiiseedlings grown with Calamagrostis rubescens. Tissue nitrogen did not differ between these treatments. The results show that Glomus intraradices colonization of Pinaceae is most successful when a VAM host is present, although some vesicular colonization of Pinaceae occurred in the absence of a VAM host. Accepted: 24 September 1997     

Charting the isophasic endophyte of dwarf mistletoe Arceuthobium douglasii (Viscaceae) in host apical buds

• Background and Aims Dwarf mistletoes (Arceuthobium; Viscaceae)are highly specialized dioecious angiosperms parasitic on manygymnosperm hosts in the northern hemisphere. Several dwarf mistletoespecies are capable of inducing an unusual form of isophasicinfection in which the internal (endophytic) system proliferateseven into the apical buds of its hosts. Studies of the internalendophytic system have, for the most part, focused on the parasitewithin secondary host tissues. The present anatomical and ultrastructuralstudy characterizes the growth pattern of the isophasic endophyticsystem of Arceuthobium douglasii within the dormant apical budsof Pseudotsuga menziesii. • Methods Semi-thin serial sections from dwarf mistletoe-infectedhost apical buds were mounted, stained and micrographed. Graphicfiles were created from the serial micrographs and these fileswere stacked. These stacked files were utilized to describethe pattern of growth of the endophyte within the host tissue.The interface between cells of the mistletoe and host was alsoexamined at the ultrastructural level by transmission electronmicroscopy. • Key Results By utilizing a novel technique of superimposedgraphics, the current study reveals an organized pattern ofmistletoe distribution that penetrates further into host tissuesthan previously known. A consistent pattern of growth occurringeven into the preformed leaves of the host is documented. • Conclusions The apparently non-intrusive growth of theparasite appears to be developmentally synchronized with thatof the host. No symplastic connections were observed in theultrastructural examination of the parasite/host interface withinthe apical buds of Pseudotsuga menziesii parasitized by A. douglasiior of Pinus contorta parasitized by A. americanum.     

Assessing the climatic sensitivity of Douglas-fir at its northern range margins in British Columbia, Canada

Northern hemisphere tree species growing at their northern range margins may be particularly responsive to climate change and could provide important information regarding future broad-scale responses. We analyzed and compared tree-ring data between five Douglas-fir [Pseudotsuga menziesii var. glauca (Mirb.) Franco] populations growing at the species’ northernmost distribution in British Columbia, Canada, and five populations located 150 km to the southeast. We quantified climate–growth relationships using uni- and multivariate techniques at different temporal scales. Our data suggest that (1) even at its northernmost distributions, precipitation limits long-term mature Douglas-fir radial growth more than temperatures, (2) northernmost Douglas-fir populations are distinct from populations located further within the species’ range in terms of certain key short-term growth responses, and (3) northernmost Douglas-fir growth sensitivities to climate may be increasing over time. In the future, mature Douglas-fir productivity in the northern portion of its range may be primarily limited by precipitation, and responses may be strongest at the species’ range margins.     

Effects of nitrate,ammonium and pH on the growth of conifer seedlings and their production of nitrate reductase

Summary Lodgepole pine (Pinus contorta Dougl.), Engelmann spruce (Picea engelmanni Parry), and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown in open-ended tube cultures of sand and perlite, irrigated with nitrate, ammonium, and a 1∶1 mixture of ammonium and nitrate, combined factorially with pH values of 4.6, 5.3 and 6.0 giving a total of nine treatments. Douglas-fir showed intolerance to ammonium which was especially marked in root weight. Lodgepole pine and Engelmann spruce made poor growth with nitrate, but showed little difference between ammonium and mixed sources. Only Douglas-fir showed a significant response to pH treatments with pH 5.3 plants being largest. Contamination of the sand with carbonate-bicarbonate, apparently caused seedlings grown in ammonium solutions to be larger in sand than in perlite. Douglas-fir grown in perlite cultures showed a growth response like the first experiment and nitrate reductase activity in the order nitrate > nitrateammonium mixture > ammonium. Plastic bead cultures had poor growth response due to low retention of water by the substrate, but the nitrate reductase assays produced results like the perlite cultures. Lodgepole pine grown in water culture demonstrated the well known pH shift associated with different nitrogen forms, and when assayed for nitrate reductase these seedlings had larger relative activities than Douglas-fir, but the order of activity remained nitrate > mixed source > ammonium.     

Inheritance of restriction fragment length polymorphisms and random amplified polymorphic DNAs in coastal Douglas-fir

A total of 225 new genetic loci [151 restriction fragment length polymorphisms (RFLP) and 74 random amplified polymorphic DNAs (RAPD)] in coastal Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] have been identified using a three-generation outbred pedigree. The Mendelian inheritance of 16 RFLP loci and 29 RAPD loci was demonstrated based on single-locus segregation in a sample of F₂ progeny. One RFLP locus, PtIFG2025, showed segregation distortion. Probe pPtIFG2025 is a loblolly pine cDNA probe encoding for rbcS. The 16 RFLP loci and 23 allozyme loci were also assayed in a sample of 16 Douglas-fir seed-orchard clones. Allelism was determined at 11 of the 16 RFLP loci. RFLPs were able to detect slightly more variation (4.0 alleles per locus) than allozymes (3.1 alleles per locus). The inheritance of an additional 80 RAPD loci was determined based on haploid segregation analysis of megagametophytes from parent tree 013-1. Once 200–300 markers are identified and placed on a genetic map, quantitative trait loci affecting bud phenology will be mapped.     

Efficiency of Countercurrent Distribution, Sephadex G-10, and Silicic Acid Partition Chromatography in the Purification and Separation of Gibberellin-like Substances from Plant Tissue

The effectiveness of countercurrent distribution, Sephadex G-10column chromatography and silicic acid partition column chromatographyin the purification of gibberellin-like substances from extractsof etiolated Phaseoltu multiflorus seedlings, and elongatingvegetative shoots of Arizona cypress (Cupressus arizonica Greene)and coastal Douglas-fir (Pseudotsuga menziesii var. menziesii)was followed by the use of the barley half-seed -amylase bioassayand dry-weight measurements. Countercurrent distribution resultedin a 10- to 30-fold reduction in the dry weight of the acidic,ethyl acetate-soluble fraction. Sephadex G-10 column chromatographyfurther lowered the dry weight by about two-thirds. Silicicacid partition column chromatography separated gibberellin-likesubstances from each other and again reduced the dry weight.Enhancement of bioassay activity was noted at each step of thepurification procedure. It is concluded that the above proceduresconstitute useful and efficient tools for the initial purificationof gibberellin-like substances from plant tissue.     

The influence of bark on the fermentation of Douglas-fir whitewood pre-hydrolysates

Douglas-fir (Pseudotsuga menziesii) whitewood was supplemented with increasing concentrations of bark (0–30%) and was pretreated using SO₂-catalysed steam explosion. The presence of bark in the feedstock resulted in the decreased recovery of total sugars, furfural and 5-hydroxymethylfurfural in the resultant pre-hydrolysate. No detrimental impact on monomer sugar recovery was observed. The concentration of lipophilic extractives present in the pre-hydrolysate increased with increasing bark loading, to a maximum of 0.43 g l^–1. The water-soluble pre-hydrolysates were fermented by Saccharomyces cerevisiae to determine the impact of bark on sugar consumption and ethanol production. Despite the inclusion of bark, fermentation of all pre-hydrolysates resulted in the complete consumption of hexose sugars within 48 h. Ethanol yields were greater than 0.43 g g^–1 for all pre-hydrolysates regardless of bark content, indicating that, up to a content of 30%, bark had a negligible impact on the fermentation of the pre-hydrolysates to ethanol. Electronic Publication     

Partial DNA sequencing of Douglas-fir cDNAs used for RFLP mapping

 DNA sequences from 87 Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) cDNA RFLP probes were determined. Sequences were submitted to the GenBank dbEST database and searched for similarity against nucleotide and protein databases using the BLASTn and BLASTx programs. Twenty-one sequences (24%) were assigned putative functions; 18 of which were from plant species. Six sequences aligned with conifer genes, including genes from Douglas-fir. Similarities among the 87 sequences were revealed by analyses with FASTA, suggesting either redundancy or isoforms of the same gene. Assignment of putative functions to anonymous cDNA mapped markers will increase the understanding of structural gene organization of the Douglas-fir genome. Received: 10 April 1998 / Accepted: 29 April 1998     

Nutrient Cycling in an Age Sequence of Western Washington Douglas-fir Stands

The cycling of nitrogen, phosphorus, calcium, magnesium andpotassium in a series of western Washington Douglas-fir [Pseudotsugamenziesii (Mirb.) Franco] stands ranging in age from 9 to 95years has been described. The stands were of relatively lowproductivity being limited by low nitrogen. The content of nitrogen,phosphorus, magnesium and potassium in tree foliage all tendedto stabilize at about 40 years whereas calcium continued toincrease. The content of all nutrients in the wood continuedto increase with stand age. Nitrogen in the forest floor accumulatedconstantly at about 5.7 kg ha^–1 year^–1 and thistogether with the above-ground tree accumulation meant about10.5 kg ha^–1 year^–1 nitrogen was immobilized. Calciumalso increased with time in the forest floor with age whereasthe other nutrients were fairly constant after about 30 years.Understorey nutrient content reached a peak at about 20 years,while understorey litter-fall was significant throughout theage sequence. Internal redistribution, especially of nitrogen,represented an increasingly greater proportion of stand requirementwith increasing stand maturity. Pseudotsuga menziesti (Mirb.) Franco, Douglas-fir, biomass, litter-fall, nutrient content, nutrient cycling     

The Effect of Artificial Wind on the Growth-rate of Plants in Water Culture: With Plate and three Figures in the Text

Young plants of Brassica napus (rape), Hordeum vulgare, andPisum sativum growing in water culture have been exposed tofour continuous wind speeds for from 4 to 5 days. The plantswere exposed to natural daylight, humidity, and temperaturein a wind tunnel in which only air movement was controlled.The wind speeds found among the plants in the four sectionsof this tunnel were approximately 0·3, 0·7, 1·7,and 4·0 m./sec. The results showed no significant changein relative growth-rate or net assinilation rate with wind speed. Previously published results, obtained with plants in soil orsand culture, have differed from those in the present experimentsin showing a fall in the amount of growth as wind speed increased.It is suggested that the reduction in growth found in theseprevious experiments was caused by partial drying out of theplants, whilst in the present experiments water-supply to theroots was abundant and this effect was considerably reduced.     

Direct Somatic Embryoid Formation on Immature Embryos of Trifolium repens, T. pratense and Medicago sativa, and Rapid Clonal Propagation of T. repens

By direct somatic embryogenesis in vitro a clone of asepticplantlets can be raised from a single immature embryo of Trifoliumrepens (white clover) within about 6 weeks of pollination. Embryoidsare induced directly from intact zygotic embryonic tissue ona culture medium containing 0·025 or 0·05 mg 1^–1BAP and 1·0 g 1^–1 yeast extract. Similar directsomatic embryogenesis has also been achieved for Trifolium pratense(red clover) and Medicago sativa (lucerne). Applications ofembryo propagation by direct somatic embryogenesis are discussed,particularly in relation to multiple screening of host genotypesfor analysis of host/pathogen and legume/Rhizobium interactions. Trifolium repens L., Trifolium pratense L., Medicago sativa L., clover, lucerne, tissue culture, embryoid, somatic embryogenesis, legumes     

The Detection of the Accumulation of Silicon in Phalaenopsis (Orchidaceae)

Small particles along the veins of leaves in Phalaenopsis containsilicon. The silica bodies are spherical in shape and 5-20 µmin diameter. In the in vitro cultured plantlets, they grow differentlyin size, depending on the developmental stage of the plantletsand the concentration of silicon added to the medium. The growthof the silica body was increased by increasing the concentrationof CaSiO₃ from 0·01 to 0·5 mg l^-1 and was maximizedfrom 0·5 to 1·0 mg l^-1. In the medium with 1·0mg l^-1 CaSiO₃, they grew to a size larger than that of the greenhouseplants after 6 months in culture. The sensitivity of the growthof the silica bodies to the environmental concentration of siliconwas then suggested to be a useful indicator for studying theuptake of silicon in plants.Copyright 1995, 1999 Academic Press Phalaenopsis, Orchidaceae, silica body, stegmata     

Analysis of the Nitrogen Response of Leaf Extension in Lolium temulentum Seedlings

Lolium temulentum seedlings were grown on a nutrient mediumcontaining NH₄NO₂ at 0, 0·1, 0·5, 1·0 and4·3 mmoll^–1 as the sole N source. Relative andabsolute extension rates, maximal leaf size, duration of extensiongrowth, rate of leaf appearance and plastochron index were determinedfrom the parameters of Richards functions fitted to lengthsof laminae measured at intervals after sowing. The final lengthof leaf I was relatively insensitive to N whereas mean relativeextension rate was increased and duration of growth decreasedwith increasing NH₄NO₂ concentration. Leaves 2 and 3 enlargedprogressively with N at concentrations up to 1·0 mmoll^–1but were unresponsive thereafter. There was no significant correlationbetween final length and mean relative extension rate for leaves1 to 3. Leaves 4 to 6 continued to show increasing length beyond1·0 mmoll^–1 N and final length was significantlycorrelated with mean relative extension rate. Increasing N increasedthe rate of leaf appearance by decreasing the duration of leafextension and plastochron. These results are discussed in relationto the control of leaf and N turnover. Lolium temulentum, rye grass, leaf extension, nitrogen, Richards function, growth analysis     

Mycorrhiza-like interaction by Morchella with species of the Pinaceae in pure culture synthesis

 Isolates from two species of Morchella were tested for ability to form mycorrhizae in pure culture synthesis with Arbutus menziesii, Larix occidentalis, Pinus contorta, Pinus ponderosa, andPseudotsuga menziesii. Ectomycorrhizal structures (mantle and Hartig net) formed with the four species of the Pinaceae but not with A. menziesii. Results are compared to previous studies on morel mycorrhizae and discussed in an ecological context. Accepted: 23 October 1999     

Nitrogen Utilization in N-limited Barley During Vegetative and Generative Growth: III. POST-ANTHESIS KINETICS OF NET NITRATE UPTAKE AND THE ROLE OF THE RELATIVE ROOT SIZE IN DETERMINING THE CAPACITY FOR NITRATE ACQUISITION

Barley (Hordeum vulgare L., cvs Golf, Mette, and Laevigatum)was grown under nitrogen limitation in solution culture untilnear maturity. Three different nitrogen addition regimes wereused: in the ‘HN’ culture the relative rate of nitrate-Naddition (RA) was 0·08 d^–1 until day 48 and thendecreased stepwise to, finally, 0·005 d^–1 duringgrain-filling; the ‘LN’ culture received 45% ofthe nitrogen added in HN; the ‘CN’ culture was maintainedat RA 0·0375 d^–1 throughout. Kinetics of net nitrateuptake were measured during ontogeny at 30 to 150 mmol m^–3external nitrate. V_max (which is argued to reflect the maximuminflux rate in these plants) declined with age in both HN andLN cultures. A pronounced transient drop was observed just beforeanthesis, which correlated in time with a peak in root nitrateconcentration. Similar, but less pronounced, trends were observedin CN. The relative V_max (unit nitrogen taken up per unit nitrogenin plants and day) in all three cultures declined from 1·3–2·3d^–1 during vegetative growth to 0·1–0·7d^–1 during generative growth. These values are in HN andLN cultures 15- to more than 100-fold in excess of the demandset by growth rates throughout ontogeny. Predicted balancingnitrate concentrations (defined as the nitrate concentrationrequired to support the observed rate of growth) were below6·0 mmol m^–3 in HN and LN cultures before anthesisand then decreased during ontogeny. In CN cultures the balancingnitrate concentration increased during grain-filling. Apartfrom the transient decline during anthesis, most of the effectof ageing on relative V_max can be explained in terms of reducedcontribution of roots to total biomass (R:T). The loss in uptakeper unit root weight is largely compensated for by the declinewith time in average tissue nitrogen concentrations. The quantitativerelationships between relative V_max and R:T in ageing plantsare similar to those observed for vegetative plants culturedat different RAs. The data support the contention that the capacity for nitrateacquisition in N-limited plants is under general growth control,rather than controlled by specific regulation of the biochemicalpathway of nitrate assimilation. Key words: Barley, nitrogen concentration, root: total plant biomass ratio, V_max