Search

Effects of 10-year storage on germination of seeds in 191 Anatolian Black Pine trees from 23 populations in the Lakes Region of Turkey were investigated. Germination tests were conducted with both fresh (in year 1999) and stored (in year 2009) seeds and variation in germination was related to geographic features of the populations. Significant reductions in germination rate (from 79.93% to 30.68%) and germination percentage (from 95.99% to 58.41%) were observed after 10-year storage. Germination characteristics seem to be associated with humidity of population locations. Seeds from more inland (i.e., continental) populations germinated slower but attained higher germination percentage for both seed sets. Germination percentage of stored seeds is highest at elevations with high humidity. Greater attention should be given to environmental conditions of seed sources in storing Anatolian Black Pine seeds in the Lakes Region of Turkey as it is a very important tool in ensuring continuous seedling production and genetic conservation. [ABSTRACT FROM AUTHOR]

In order to assess the impact of seed removal and seedling establishment for four species of pines, we designed experiments with and without the exclusion of seed removers in three vegetation types (pine forest, oak-alder forest, and subalpine grassland). Seed removal was significantly different between species of pines ( P < 0.01), as was the interaction between the vegetation types and category of exclusion (remover) ( P < 0.0001). The significant difference in terms of seed removal was between P. patula and P. montezumae (33.0 and 17.9%, respectively). Seed removal was significant between pine forest-without exclusion (20.0%) versus oak-alder forest-without exclusion (7.0%). There was significant interaction between seedling establishment of the pine species and vegetation type ( P < 0.0001). Highlighting differences between the pine forest- P. teocote (84.1%) versus oak-alder forest- P. patula (19.0%), oak-alder forest- P. pseudostrobus (45.0%), pine forest- P. patula (20.2%), pine forest- P. pseudostrobus (45.6%), subalpine grassland- P. montezumae (24.3%), subalpine grassland- P. patula (27.9%), and subalpine grassland- P. pseudostrobus (17.5%). The impact of the food preferences of rodents and other granivores for P. patula and P. pseudostrobus seeds, as well as the poor survival of seedlings of these species in the pine and oak-alder forest are both factors which may explain the dominance of P. teocote in the study region. [ABSTRACT FROM AUTHOR]

A pot trial was implemented to determine the effect of soil water stress following transplanting on shoot water potential and stomatal conductance of Pinus patula seedlings. The relationship of seedling morphology to measures of water stress was also investigated. The trial consisted of two watering treatments: a control (no water stress) and a severe water stress (no further water after planting). The treatments were applied to recently transplanted seedlings selected to reflect a range of sizes typical in an operational environment. Measures of shoot water potential and stomatal conductance, root and shoot growth and environmental variables were made. The results indicated that P. patula seedlings tolerated high air and soil temperatures (above 35°C) and low soil water availability (-1.5 MPa). The water potential threshold for changes in stomatal conductance was in the region of -0.8 to -0.9 MPa and stomatal closure had occurred at a shoot water potential of between -1.8 and -2.1 MPa. Mortality occurred when shoot water potential declined to below -3.0 MPa. There was variability between seedlings in their potential for survival and growth. Inherently bigger seedlings had a greater capacity for new root growth following planting. Mass of new roots was significantly and positively related to higher rates of transpiration under conditions of low soil moisture. [ABSTRACT FROM AUTHOR]

The effects of stand stem density (SSD), orientation and distance with respect to shelter trees, and fertilisation on planted Pinus sylvestris and Picea abies seedlings were examined at two sites, one with a southerly aspect (64°14′N, 19°46′E, 225 m a.s.l.) and one with a northerly aspect (64°09′N, 19°36′E, 274 m a.s.l.) in boreal forests in Sweden. The damage and growth were compared at these sites in stands with three SSD's and different light regimes: uncut forest (SSD 500, ~500 stems/ha), shelterwood (SSD 150,~150 stems/ha), and clear-cut (SSD, 0 stems). Half of the seedlings were irrigated with fertiliser (10 mM N). Fertilisation and SSD affected the height growth of P. abies, since fertilised seedlings in SSD 0 grew the most (22.2 cm). Fertilised seedlings in SSD 0 also generally had the greatest biomass (twigs, leading shoot and needles), even P. sylvestris seedlings on the North slope, where fertilised and unfertilised pine seedlings in SSD 0 had 62.6 and 39.7 g biomass, respectively. P. sylvestris increased about 150% in dry mass of leading shoot of the increase of P. abies with equal height growth, when comparing SSD 150 and SSD 0. The results indicate that the general conditions of the stand have stronger effects on the growth of planted seedlings than their orientation and distance with respect to the nearest tree and that light requirements cannot be moderated by fertilisation. We postulate that a system in which forest gaps are formed under a shelterwood could provide a way to regenerate forests that exploits the beneficial features of both shelter trees and clear-cuts. [ABSTRACT FROM AUTHOR]

Fungal cell wall elicitors have notable effects on germination of pine seeds, defence response and many other aspects of metabolic processes. In this study, we investigated morphological, physiological and molecular response of somatic embryos of Scots pine to fungal cell wall elicitors from ectomycorrhizal fungus Suillus bovinus, pathogenic fungus Heterobasidion annosum or weak Scots pine pathogen ( Heterobasidion parviporum). Results from the embryo rooting experiment indicated that the genotypic origin of the conifer tree and the source of the elicitors affected the root development. Elicitors from either S. bovinus or H. parviporum increased the root formation but increased concentration of elicitors from H. annosum decreased the rooting and survival rate of the embryos. At the molecular level, altered transcript changes were observed among genes encoding proteins involved in cell division, cell wall modification, and stress following exposure of embryos to elicitors. Increased levels of actin and peroxidase gene expression were detected at 7 days after exposure to S. bovinus or H. parviporum elicitors. H. annosum elicitors provoked significant induction of the ethylene synthesis gene PsACS-1. Generally the gene expression patterns at early stages observed in the subset of genes investigated after treatment with H. parviporum elicitor were found to be similar to that documented for S. bovinus. In contrast, somatic embryos exposed to H. annosum elicitor had different patterns of regulation marked by delayed response, and in some cases gradual degradation and death of the embryos were observed. [ABSTRACT FROM AUTHOR]

The species Pinus tropìcales Morelet is endemic of the western region of our country and of the gender Pinus, is the one that offers wide perspectives in the reforestation for its resistance capacity and adaptability in the soil of very low fertility where other species cannot be developed, but for several decades this species presents low germination percent what has diminished the populations of this important Pinus gradually. With this study we seek to evaluate the influence of the watering with (ATM) in the germination and growth of 3 origins of this species. The experiments were carried out in an experimental greenhouse located in the EEF of Viñales, it settled down a control and a treatment for each origin, with alternating watering of (ATM) for the treatments and water without trying for the control. In the case of the treatments a magnetizerr of permanent imams was used with a range of induction of 400-700 Gauss. The experiment lasted 45 days and the mensurations were made to intervals of 5 days for the germination and growth in height, the results of the treatments went superior to the control in the 3 origins, checking this physical agent's positive effect as much in the germination as in the growth of the coniferous plants of this important one. [ABSTRACT FROM AUTHOR]

Micropropagation of plants from the genus Pinus has been done in several species. However, micropropagation of Pinus cubensis Griseb has not been reported. This species has a great economical importance. Then, the aim of the current research was to achieve in vitro propagation of Pinus cubensis Griseb. to increase the number of individuals in their natural habitat. The concentration of sodium hypochlorite and immersion time were determined for seed disinfection and embryo establishment. The effect of the presence or absence of the seed coat was also studied. Two growth regulators and three concentrations of each one were tested to achieve the emission of axillary buds in the multiplication phase. Five subcultures every 21 days were done. Rooting and acclimatization were carried out simultaneously. Shoots were individualized and immersed in a rooting solution. Zygotic embryos of P. cubensis were developed in vitro. The highest percentages of disinfection and germination were obtained by introducing the seeds in a solution of sodium hypochlorite at 20% for 15 minutes, planting them after that without the seed coat. The number and length of axillary buds increased by using 22.5 μM of 6- benzylaminopurine and 5.4 μM naphthaleneacetic acid in the multiplication phase. The in vitro propagation of Pinus cubensis Griseb. from zygotic embryos was achieved for the first time. A protocol was also established, reaching 50% of survival in the acclimatization phase. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Field Ornithology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The advance of exotic tree and shrub species is one of the main threats to conservation of the last relicts of natural grassland in South America; however, control actions in the region are still scarce and there are almost no evaluations of the recovery of natural ecosystems after removing invasive plants. Monitoring of the vegetation during the years after removal of invasive trees is critical in order to decide whether an active restoration strategy is necessary. The recovery of montane grassland four years after the control of a dense invasion of Aleppo pine ( Pinus halepensis) is described in this study. Experimental clearing areas were followed during four years and compared to grassland controls. Variation was seen in the levels of recovery in function of the proximity of sectors of grassland that are free of invasive species and/or the density of invasive trees before control. Native species slowly replaced many exotic herbs that had appeared as pioneers, there was low recruitment of pine seedlings in spite of the quantity of seeds from trees that surrounded the clearings, and species richness and diversity were restored, including cover of the typical grasses in the controls. Recovery of grassland after felling was shown to be successful and does not seem to be seed limited if tree removal occurs early in the invasion process. [ABSTRACT FROM AUTHOR]

To test the effects of different protein sources and levels on performance, carcass characteristics and beef chemical composition, concentrates with three protein sources [Lupine seed (L), Rapeseed meal (R) and Soybean meal (S)] and two protein levels [‘normal protein’ (NP) or ‘high protein’ (HP)] were fed to 36 Simmental calves. Calves initially weighed 276 ± 3.9 kg and averaged 6 months of age and were randomly allocated to the six treatments. Maize silage was offered ad libitum and supplemented with increasing amounts of concentrates (wheat, maize grain, protein sources, vitamin–mineral mix). Normal protein and HP diets were formulated to contain 12.4% and 14.0% crude protein (CP) dry matter (DM) respectively. At the end of the fattening period of 278 days, the final live weight averaged 683 ± 14.7 kg. Neither level of protein nor its interaction with protein sources had any effects on most of the traits studied. Feeding the R diet significantly increased final weight, average daily gain (ADG), DM intake and CP intake in relation to the L diet; no differences were observed between the L and S diets for these measures. No differences were observed between the R and S groups in final weight or ADG, but the calves fed the R diet consumed more DM and CP than the calves fed the S diet. Bulls fed R diet had higher carcass weight and dressing percentage than the L groups, and no significant differences were detected between the S and L groups. Chemical composition of the Musculus longissimus dorsi was not significantly affected by source of protein. Also, the major saturated fatty acid (SFA) (C16:0 and C18:0) did not significantly differ among the three treatments. Samples from R group had significantly higher proportions of C16:1 t9, C18:1 c11, C18:2 c9 t11, C18:3 c9, 12, 15 and ΣC18:1 t fatty acids in relation to L and S groups. Although polyunsaturated fatty acid/SFA ratio was similar for the three dietary groups, n-6 /n-3 ratio and Σn-3 fatty acids content were significantly greater for bulls fed R diet in relation to those fed L and S diets. [ABSTRACT FROM AUTHOR]

Evaluation was made of four extraction techniques (maceration with magnetic stirring, ultrasound-assisted extraction, microwave-assisted extraction, and extraction with pressurised liquids) to obtain polyphenolic extracts from pine seeds. The technique and temperature conditions that produce extracts containing the largest quantity of polyphenols were determined. Extraction assisted by microwave and extraction with pressurised liquids at temperatures >100°C gave the best results. The correlation between the antioxidant activity of the extracts and the quantity of polyphenols that they contain has also been determined; a direct relationship between these two variables was found in the majority of extracts. The general biological activity of the extracts was also evaluated using the etiolated wheat coleoptile bioassay; extracts obtained with pressurised liquids, and with maceration under agitation, were the most bioactive. An inverse relationship between the degree of bioactivity and the extraction temperature was found. [ABSTRACT FROM AUTHOR]

The subalpine communities of Pinus mugo were destructed and replaced by pasture lands on plateau parts and moderately inclined slopes of the mountains during between the 15th andthe 18th centuries. The species were able to survive that pressure probably on the abrupt slopes of the glacial cirques. The pasturing stopped in the 19th century, andthe mountain pine started to reforest its previous habitats since that time. It was also plantedin several places and some of contemporary populations can origin from the seeds of the Giant Mountains. In the latter case the populations on the plateau shall reveal differences in the cone characters from autochtonous ones from the glacial cirques. This study was structured on this hypothesis. The characteristics of seven Pinus mugo populations in the Giant Mts. were comparedon the basis of 15 morphological characters of cones. Each population was represented by at least 30 individuals, and for every individual 10 cones were examined. Four of the sampled populations, treated as local, occurred on the steep slopes of the glacial cirques andthe other three on the mountain plateaus, use das pastures in the 17th to 18th centuries, potentially originated from another region. Results show rather small differences among the compared populations, independently of origin. The separation of the plateau from the steep slope ones is rather inconspicuous, if any. This suggests the local origin of plateau populations, even when planted. [ABSTRACT FROM AUTHOR]

Abstract: New native pine forests provide potential new habitat for colonisation by stipitate hydnoid fungi but their ability to colonise and persist in these areas is unknown. Soil containing Scots pine seedlings and inoculum of Hydnellum peckii was transferred to Darroch Wids, which is a newly planted native forest on former agricultural land. Both H. peckii and Phellodon tomentosus were transferred to White Bridge, which once would have supported native Scots pine forest. Below-ground persistence of the inoculum was monitored by amplification of ITS sequences from soil DNA and RNA using species-specific primers, and root systems were screened for the presence of ectomycorrhizas of both target species. H. peckii DNA was consistently detected over 2.5y in soil taken from the Darroch Wids site. The number of detections of H. peckii and P. tomentosus DNA at White Bridge showed a sharp decline over 1y. RNA of the target species was detected in the majority of samples, however, no ectomycorrhizas were found at White Bridge. This suggests that establishment of new colonies of H. peckii and P. tomentosus is unpredictable. [Copyright &y& Elsevier]

Abstract: This study investigated the effects of inoculation with three individual ectomycorrhizal (ECM) fungal species on soil microbial biomass carbon and indigenous bacterial community functional diversity in the rhizosphere of Chinese pine (Pinus tabulaeformis Carr.) seedlings under field experimental conditions. The results showed that ECM fungal inoculation significantly increased the ectomycorrhizal colonization compared with non-inoculated seedlings. ECM fungal inoculations have higher soil microbial biomass carbon than that of control, ranging from 49.6 μg C g−1 dry soil in control to 134.02 μg C g−1 dry soil in treatment inoculated with Boletus luridus Schaeff ex Fr. Multivariate analyses (PCA) of BIOLOG data revealed that the application of ECM fungi significantly influenced bacterial functional diversity in the rhizosphere of P. tabulaeformis seedlings. The highest average well-color development (AWCD) and functional diversity indices were also observed in treatment inoculated with B. luridus. A wider range of sole carbon sources were utilized by the bacterial community in the rhizosphere of inoculated seedlings. The data gathered from this study provides important information for utilization of ECM fungi in forest restoration project in the Northwestern China. The present study will also significantly broaden our understanding of practical importance in the application of ECM fungal inoculum to promote soil microbial community diversity of soil. [Copyright &y& Elsevier]

Young seedlings of maritime pine (Pinus pinaster Soland in Aït.) were grown in rhizoboxes using intact spodosol soil samples from the southwest of France, in Landes of Gascogne, presenting a large variation of phosphorus (P) availability. Soils were collected from a 93-year-old unfertilized stand and a 13-year-old P. pinaster stand with regular annual fertilization of either only P or P and nitrogen (N). After 6 months of culture in controlled conditions, different morphotypes of ectomycorrhiza (ECM) were used for the measurements of acid phosphatase activity and molecular identification of fungal species using amplification of the ITS region. Total biomass, N and P contents were measured in roots and shoots of plants. Bicarbonate- and NaOH-available inorganic P (Pi), organic P (Po) and ergosterol concentrations were measured in bulk and rhizosphere soil. The results showed that bulk soil from the 93-year-old forest stand presented the highest Po levels, but relatively higher bicarbonate-extractable Pi levels compared to 13-year-old unfertilized stand. Fertilizers significantly increased the concentrations of inorganic P fractions in bulk soil. Ergosterol contents in rhizosphere soil were increased by fertilizer application. The dominant fungal species was Rhizopogon luteolus forming 66.6% of analysed ECM tips. Acid phosphatase activity was highly variable and varied inversely with bicarbonate-extractable Pi levels in the rhizosphere soil. Total P or total N in plants was linearly correlated with total plant biomass, but the slope was steep only between total P and biomass in fertilized soil samples. In spite of high phosphatase activity in ECM tips, P availability remained a limiting nutrient in soil samples from unfertilized stands. Nevertheless young P. pinaster seedlings showed a high plasticity for biomass production at low P availability in soils. [ABSTRACT FROM PUBLISHER]

The degree to which forest ecosystems provide a long-term sink for increasing atmospheric CO2 depends upon the capacity of trees to increase the availability of growth-limiting resources. It has been widely speculated that trees exposed to CO2 enrichment may increase the release of root exudates to soil as a mechanism to stimulate microbes to enhance nutrient availability. As a first test to examine how the atmospheric CO2 and nitrogen availability affect the rates of root exudation, we performed two experiments in which the exudates were collected from loblolly pine (Pinus taeda L.) seedlings that were grown in controlled growth chambers under low and high CO2 and at low and high rates of N supply. Despite the differences in experimental design between the two studies, plants grown at high CO2 were larger, and thus whole plant exudation rates were higher under elevated CO2 (P = 0.019), but the magnitude of this response depended on the N level in both studies. Seedlings increased mass-specific exudation rates in response to elevated CO2 in both experiments, but only at low N supply. Moreover, N supply had a greater impact on the exudation rates than did CO2, with mass-specific exudation rates significantly greater (98% and 69% in Experiments 1 and 2, respectively) in the seedlings grown at low N supply relative to high N supply. These results provide preliminary evidence that loblolly pines alter exudation rates in response to both CO2 concentration and N supply, and support the hypothesis that increased C allocation to root exudates may be a mechanism by which trees could delay progressive N limitation in forested ecosystems. [ABSTRACT FROM PUBLISHER]

Disregarded for centuries, Mediterranean pine forests in Spain have been severely affected by human activities including fires and livestock grazing. As a consequence, reforestation programs were started by the late 1800s, albeit the origin of the seeds was not considered until the late 1960s. In July 2005, a large Pinus pinaster Ait. forest, located in Guadalajara (central Spain), burned down. In this area, we studied fire-related fitness traits in natural stands (zone N) and compared them to those of trees sown with seeds from foreign sources (zone S). Cone production per hectare in zone N doubled that found in zone S. In addition, zone N resulted in more saplings per hectare as well as more small trees bearing cones than zone S. In zone S, trees showed thicker crowns and less fructification resulting in open formations with low intraspecific competition. Whereas in the natural stands the average percentage of serotiny per tree was 32%, in the sown stands only one serotinous cone was found in seven unburned harvested trees. Compared with zone S, the presence of seedlings after springtime was almost nine times higher in zone N in spite of the damaging effects of logging and removal of burnt wood. [ABSTRACT FROM AUTHOR]

Amylases have significant importance in broad industrial application including bio-ethanol production. Although amylases are widely distributed in microbes, plants and animals, it has been sought for new amylases from various sources with special industrial potential. In this study we firstly isolated and characterized a novel thermostable α-amylase from Korean pine seed. Enzyme was purified to homogeneity level with purification fold of 1286.1 using several techniques such as self-precipitation, (NH4)2SO4 fractionation, DEAE anion exchange and starch affinity chromatography. The purified α-amylase showed two bands in SDS-PAGE with molecular weight of 44 and 45kDa. The apparent molecular weight of native enzyme was calculated to be 46.7kDa. Internal peptide sequencing confirmed that the purified α-amylase was a novel enzyme. The optimum pH and temperature for enzyme activity were pH 4.5 and 65°C, respectively. This enzyme was fully stable for 48h at 50°C and retained 80% activity up to 96h. The K m and V max were 0.84mg/ml and 3.71μmol/min, respectively. On the basis of high thermal stability and a broad range of pH stability, the pine seed α-amylase showed a good prospect of industrial application. [Copyright &y& Elsevier]

The preferences of the deer mouse (Peromyscus maniculatus (Wagner, 1845)), southern red-backed vole (Myodes gapperi (Vigors, 1830)), heather vole (Phenacomys intermedius Merriam, 1889), long-tailed vole (Microtus longicaudus (Merriam, 1888)), and meadow vole (Microtus pennsylvanicus (Ord, 1851)) for lodgepole pine (Pinus contorta Dougl. ex Loud.), white spruce (Picea glauca (Moench.) Voss), and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) seeds were investigated using cafeteria-style feeding experiments. Seed selection by P. maniculatus and M. gapperi in the field was also studied. Peromyscus maniculatus, M. gapperi, M. longicaudus, and M. pennsylvanicus showed a distinct preference for lodgepole pine seeds and avoidance of subalpine fir seeds, and consumed the different species of seeds in similar relative proportions. Phenacomys intermedius behaved very differently from the other rodent species in that it did not show a preference among seed species, and consumed very few seeds in total. Findings from the field seed selection trials were consistent with laboratory results. We suggest that postdispersal seed predation by small mammals could limit the recruitment success of lodgepole pine and white spruce, but would not be a major problem in the regeneration of subalpine fir stands. This could provide an advantage for subalpine fir over neighbouring competitive species. [ABSTRACT FROM AUTHOR]

Animals that scatter hoard seeds in the same habitat potentially compete for those cached seeds when they forage for stored food. Yellow pine chipmunks, Tamias amoenus, and golden-mantled ground squirrels, Spermophilus lateralis, scatter hoard Jeffrey pine, Pinus jeffreyi, seeds differently; chipmunks make small, shallow caches whereas ground squirrels make large, deep caches. We hypothesized that ground squirrels bury seeds deeply to avoid pilferage from chipmunks, but it was unclear how chipmunks avoid pilferage by ground squirrels. We investigated this competitive interaction by making an array of caches of differing sizes and depths in rodent-proof enclosures in the field and allowed naïve subjects to forage. Ground squirrels (N =8) were unable to find caches at any depth (0/384 caches=0%) but chipmunks (N =9) found 34.3% of caches present (148/432 caches), including many deeper caches resembling those that ground squirrels make. In the laboratory, ground squirrels found four species of cached seeds at chance levels (13.1% observed versus 16.7% expected from random digging), whereas chipmunks performed well above random (34.2% versus 16.7%). These results suggest that chipmunk caches are not vulnerable to ground squirrel pilfering and that ground squirrels cannot detect and remove buried seeds easily and must forage for seeds on plants or on the soil surface. Ground squirrels apparently avoid pilfering by chipmunks by larder hoarding most seeds and defending the larder. Differences in the hoarding behaviour of these species reduce competition and promote coexistence. [Copyright &y& Elsevier]

Copyright of Annals of Forest Science (EDP Sciences) is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fusarium circinatum is the causal agent of pitch canker disease on numerous Pinus spp. This aggressive fungus may infect pine seed cryptically and, therefore, can easily be spread long distances by the seed trade. F. circinatum has recently been listed as a quarantine organism in numerous countries throughout the world, which prompted the development of a specific and sensitive tool for the detection of this pathogen in conifer seed. A new detection protocol for F. circinatum based on a biological enrichment step followed by a real-time polymerase chain reaction (PCR) assay was developed. Several enrichment protocols were compared and a 72-h incubation of the seed with potato dextrose broth was the most efficient technique to increase F. circinatum biomass before DNA extraction. The relative accuracy, specificity, and sensitivity of the real-time PCR assay was evaluated in comparison with a previously published conventional PCR test on 420 seed DNA extracts. The real-time PCR described here proved to be highly specific and significantly more sensitive than the conventional PCR, and enabled the detection of F. circinatum in samples artificially contaminated with less than 1/1,000 infected seed, as well as in naturally infected samples. Last, in order to routinely check the quality of the seed DNA extracts, a primer—probe combination that targets a highly conserved region within the 18S ribosomal DNA in plants or fungi was successfully developed. This assay allows for quick and reliable detection of F. circinatum in seed, which can help to prevent long-distance spread of the pathogen via contaminated seed lots. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate the effect of a sewage sludge-based compost (SSC) on the growth and mineral composition of containerized Pinus pinea L. seedlings. In the first experiment, five different substrates were tested: four binary mixtures of SSC and peat (100% SSC, 75% SSC, 50% SSC and 25% SSC, by volume) without fertilization, and a control substrate (peat-based substrate + fertilizer). Seedlings growing in the 100% SSC substrate showed the lowest growth, a consequence of both the low water availability and the high electrical conductivity that made SSC unsuitable to be the only component of a growing-media for pine 'seedlings'. The 50% SSC substrate presented physical and chemical properties similar to the control substrate and near the acceptable range for a growing-media. Moreover, no significant differences were found between growth of seedlings from treatment 50% SSC (without mineral fertilization) and seedlings from control treatment (with mineral fertilization). In the second experiment, a fertilization assay was performed with two substrates selected from the first experiment (50% SSC and control). The two substrates were fertilized with three levels of a macronutrient fertilizer (0.5, 1.0 and 2.0 g L-1) and two levels of a micronutrient fertilizer (0 and 0.4 g L-1 of fertilizer containing only micronutrients). Results obtained suggest that replacing 50% (by volume) of peat-based substrate by the sewage sludge-based compost allowed: maintenance of the commercial value of seedlings; reduction of the amount of peat used in the substrate; a need for only half the amount of macronutrient fertilizer applied in the basal fertilization; and omission of micronutrient fertilization. [ABSTRACT FROM AUTHOR]

Abstract: Pine plantations coexist with Stipa tenacissima grasslands in many semiarid western Mediterranean areas. We compared three microsites created by a 30-year-old Pinus halepensis plantation: below pine plantation line (BP), below canopy of pines (BC) and interline bare band (BA). They were evaluated in terms of soil properties, pine litter and suitability as recruitment niches for S. tenacissima. Next, in a manipulative experiment in growth chambers we tested the hypothesis that pine litter interferes with the seedling emergence of S. tenacissima. Three treatments in pots were compared: (a) soil from BA; (b) intact soil+litter from BP; and (c) soil+litter from BP, which was mixed in the laboratory (BPMX). In the field the main microsite differences were pine cover and litter cover and thickness. Seedling emergence was significantly greater in BA than in BP. Emergence and litter depth fits a linear regression model. In the growth chamber litter did not interfere with the emergence of S. tenacissima. However, seedlings grown without litter were 28% longer and their mass was 27% greater than in the litter treatments. The detected pine litter interference may be relevant for plant dynamics and might be considered in forestry management programs. [Copyright &y& Elsevier]

Abstract: Most measurements of nutrient uptake use either hydroponic systems or soil-grown roots that have been disturbed by excavation. The first objective of this study was to test how root excavation affects nitrate uptake. Rates of NO3 − uptake by mycorrhizal loblolly pine (Pinus taeda L.) seedlings were measured in intact sand-filled columns, hydroponics, and disturbed sand-filled columns. Total nitrate uptake in intact sand-filled columns was higher than in disturbed columns, indicating that disturbance lowers uptake. Transferring plants from the sand-filled columns to hydroponics had little effect on NO3 − uptake beyond delaying uptake for an hour. The second objective of this study was to determine whether NH4 +, Ca2+, Mg2+ and K+ uptake could be studied using sand-filled columns, since previous studies had tested this method only for nitrate uptake. Uptake rates of NH4 + and K+ were positive, while Ca2+ and Mg2+ uptake rates were negative in intact sand-filled columns, indicating that net efflux may occur even without physical disturbance to the root system. The sand-filled column approach has some limitations, but holds promise for conducting nutrient uptake studies with minimal disturbance to the root system. [Copyright &y& Elsevier]

Pinus roxburghii (chir pine or long-needle pine) is considered to be a fire-hardy species. In this study the effect of a wide range of elevated temperatures (from 40 °C to 150 °C) on cone bursting and subsequent seed germination was examined in five provenances of P. roxburghii in comparison to sun drying. The maximum germination percentage (88.6 ± 1.46%; mean ± SE) was recorded with seeds from the Jasholi provenance extracted from cones dried artificially at 40 °C and germinated at 25 °C. At bursting these cones retained 6.9 ± 0.83% moisture content and the seeds retained 8.8 ± 0.32% moisture content. The germination percentage of the seeds from the Jasholi provenance extracted at 150 °C, at which temperature cone bursting occurred within 45 min, was only 22.2% when germinated at 30 °C. These cones retained 4.8 ± 0.54% moisture content and the seeds retained 7.0 ± 0.42% moisture content after bursting. In general, increasing temperature above 40 °C was inversely proportional to seed germinability. [ABSTRACT FROM AUTHOR]

A pot trial was carried out for 10 months to investigate the effects of ectomycorrhizal (ECM) fungal infection and phosphorus (P) fertilization on the growth of newly germinated Pinus radiata D. Don seedling, P uptake by the seedlings and rhizosphere properties. The experiment consisted of two phosphate rock (PR)-P application rates [0 and 100 mg P kg- 1 soil supplied as Ben Guire PR (BGPR)] and 5 soil treatments (autoclaved soil, fungicide-treated soil, untreated natural soil, and Rhizopogon rubescens Tul. and Suillus luteus (L. ex. Fr.) S. F. Gray inoculated soils). The results showed that the treatment effects were more striking in P-fertilized treatments. In P-fertilized soils, all the non-autoclaved treatments significantly increased seedling growth and P concentration and P uptake in plant tissues compared with the autoclaved treatment. The ECM inoculation produced greater phosphatase activities, higher oxalate concentration, and more plant-available P (soil solution P and resin extractable P) in the rhizosphere soils than in the bulk soils in P-fertilized soil. Compared with S. luteus, R. rubescens inoculation resulted in greater ECM tip density in seedling roots in P-fertilized treatments, indicating that R. rubescens are more susceptible to infection of radiata seedling roots. Approximately 57-69% of the BGPR added to the soil had been dissolved in 10 months after application and BGPR significantly increased seedling height, ECM root tip density, and P concentration in shoots in both autoclaved and non-autoclaved treatments. [ABSTRACT FROM AUTHOR]

During pine seed germination, a large amount of N mobilized from the storage proteins is re-allocated in the hypocotyl as free asparagine, as a result of the high levels of asparagine synthetase (AS) encoded by the PsAS1 gene. To determine the role of this re-allocated N reserve, a full-length cDNA encoding l-asparaginase (ASPG) has been cloned from Scots pine ( Pinus sylvestris L.) seedlings and characterized. Like other N-terminal nucleophile hydrolases, pine ASPG requires a post-translational processing to exhibit enzymatic activity. However, in contrast to previous reports on other plant ASPGs, purified recombinant pine ASPG does not undergo autoproteolytic cleavage in vitro. Our results suggest that the processing requires accessory proteins to assist in the proteolysis or in the proper folding before autocleavage in a divalent cation-dependent manner. Sequence comparison analysis revealed that the pine protein is included in the K+-dependent subfamily of plant ASPGs. The expression of the ASPG-encoding gene ( PsASPG) was higher in organs with extensive secondary development of the vascular system. The increase in transcript abundance observed at advanced stages of hypocotyl development was concomitant with a decrease of PsAS1 transcript abundance and a remarkable increase in the number of xylem elements and highly lignified cell walls. These results, together with the precise localization of PsASPG transcripts in cells of the cambial region, suggest that the expression of PsAS1 and PsASPG is temporally coordinated, to control the re-allocation of N from seed storage proteins toward the hypocotyl to be later used during early development of secondary vascular system. [ABSTRACT FROM AUTHOR]

The proximate composition of Aleppo pine (Pinus halepensis Mill.) seeds cultivated in Bizerta (Tunisia) were investigated for their fatty acid composition, and their thermal and physical properties of lipid fraction. The proximate analysis of pine seeds showed the following composition (on a dry-weight basis): protein 22.7%, oil 43.3%, ash 8.3% and total carbohydrate 25.7%. Potassium, magnesium and calcium were the predominant mineral elements present in the seeds and reached, together, about 1%. Oleic and linoleic acids were the major unsaturated fatty acids (27.3 and 48.8%, respectively), while the main saturated one was palmitic acid (8.75%). Myristic, myristoleic, palmitoleic, margaric, margaroleic, stearic, linolenic, arachidic, eicosenoic, eicosadienoic eicosatrienoic behenic and lignoceric acids were also detected. Thermal profile of Pinus halepensis Mill. seed oil, determined by its DSC melting curve, showed that the entire liquefaction of the Aleppo pine seed oil occurs at -8°C. CieLab colour parameters (L*, a*, b*), oxidative stability by Rancimat test and viscosity were also determined. Physicochemical properties of the oil include: saponification number 190, peroxide value 3.18, iodine index 117, and a low acidity of 0.61%. Results suggested that the production of oil from Pinus halepensis seeds could provide a potential use in food, pharmaceutical, cosmetics and other non-food industries. [ABSTRACT FROM AUTHOR]

The article presents a study which investigated the pinecone opening tradition among black rats in Cyprus and in Israel. It outlines the localities in Cypurs where pinecones opened by black rats were found. It discusses the similarities between the technique used by black rats in Cyprus and black rats in Israel in harvesting pine seeds. It relates the possibility of the independent evolution of the tradition of pine cone opening among black rats in Cyprus.

Data from 200 plots randomly selected from the Southwide Pine Seed Source Study of loblolly pine (Pinus taeda L.) were used to fit whole-stand and individual-tree equations. Another 100 plots, also randomly selected, were used for validation. Outputs from the individual-tree model were then adjusted to match observed stand attributes (number of trees, basal area, and volume per hectare) by four disaggregation methods: proportional yield, proportional growth, constrained least squares, and coefficient adjustment. The first three are existing methods, and the fourth is new. The four methods produced similar results, and the coefficient adjustment was then selected as the method to disaggregate predicted stand growth among trees in the tree list. Results showed that, compared to the unadjusted individual tree model, the adjusted tree model performed much better in predicting stand attributes, while providing comparable predictions of tree diameter, height, and survival probability. The proposed approach showed promise in the ongoing effort to link growth models having different resolutions. [ABSTRACT FROM AUTHOR]

A polymerase chain reaction (PCR)-based assay was developed for the specific detection of the fungal pathogens Diplodia pinea and D. scrobiculata from pine host tissues. Variation among mitochondrial small subunit ribosome gene (mt SSU rDNA) sequences of Botryosphaeria species and related anamorphic fungi was exploited to design primer pairs. Forward primer DpF and forward primer DsF, each when used with the nonspecific reverse primer BotR, amplified DNA of D. pinea or D. scrobiculata, respectively. Specificity was confirmed using multiple isolates of each of these two species and those of closely related fungi including Botryosphaeria obtusa. The detection limits for DNA of each pathogen in red and jack pine bark were 50 to 100 pg μl-1 and 1 pg μl-1 in red and jack pine wood. The assay was tested using naturally occurring red and jack pine seedlings and saplings exhibiting symptoms of Diplodia collar rot. Samples from lower stems/root collars of 10 dead trees of each species from each of three sites at each of two locations were tested. Results were positive for D. pinea or D. scrobiculata for the large majorities of symptomatic bark and wood samples from both locations. For positive samples, however, there were effects of location and host species on detection of D. pinea (more frequent on red pine) and D. scrobiculata (more frequent on jack pine) (P < 0.01 in both cases). These results indicate that these new primers are potentially useful for studies in areas or hosts in which both pathogens may be present. [ABSTRACT FROM AUTHOR]

The article provides information on the process used in predicting forest-tree seed dispersal. It is useful for estimating gene flow from genetically engineered or transgenic trees. The researchers used computer simulation based on measurements from a plantation established by wild forest-tree seeds since it prohibits experiments that use transgenic trees. Long-distance dispersal distances of Pinus taeda seeds were consistent with an anecdotal report of pine seed dispersal in treeless areas. The effect of leaf-area density differences was accounted.

Embryogenic cultures of loblolly pine (Pinus taeda L.), slash pine (Pinus elliottii Engelm.), longleaf pine (Pinus palustris Mill.) and slash pine × longleaf pine hybrids were initiated from immature seeds on an initiation medium containing 13.57 μM 2,4-dichlorophenoxyacetic acid and 2.22 μM benzylaminopurine. Embryogenic cultures proliferated and somatic embryos developed, matured and germinated following a modified protocol and media originally developed for radiata pine (Pinus radiata D. Don.) somatic seedling production. A discrete, light-sensitive pre-germination stage and a later germination (radicle emergence) stage were identified by the differential response of somatic embryos to light of different wavelengths. Different light quality treatments were applied during the pre-germination and germination steps, using cool white fluorescent bulbs or light-emitting diodes (LEDs), or both. In general, red wavelengths provided by LEDs during these steps resulted in higher frequencies of somatic embryo germination (up to 64%) and conversion (up to 50%), longer tap roots and more first-order lateral roots than the standard cool white fluorescent treatments or treatment with blue wavelengths from LEDs. In addition, exposure to red light allowed germination of somatic embryos of some clones that failed to produce germinants under fluorescent light. Germination and conversion were further enhanced by sequential application of cool white fluorescent light and red light, resulting in up to 100% germination and conversion in one experiment. Longleaf pine somatic embryos were especially responsive to the light quality treatments, resulting in the first report of somatic seedling production for this species. [ABSTRACT FROM PUBLISHER]

This study investigated the spatial and temporal patterns of edge effect following forest harvesting in pine-dominated hemiboreal forests. The aim of the study was to determine how the edge influenced ground vegetation and how it changed over successional time. The chronosequence approach was used for the description of the succession by taking sites in similar environments but in different periods after cutting. Five transects were established in each type of edge. All ground vegetation was recorded and the percentage cover of each species was estimated. The impact of edge effect to overall species composition was evaluated by canonical correspondence analysis. The variety of species composition along the distance from the edge was highest in clear-cut-mature stand edges. The highest species richness was found at the edges of older clear-cuts. The cover of herb layer was highest in older clear-cuts and young stands. The cover of moss layer was lower in clear-cutting areas than in nearby standing mature stands. Edge influence was still detectable up to 40 years after clear-cutting, when forest interior conditions have not yet formed. [ABSTRACT FROM AUTHOR]

Growth and nutrition of hydroponically cultivated pine seedlings ( Pinus pinaster Ait.) were investigated at various phosphorus (P) availabilities. P was added either with free access or at a relative addition rate of 0.02 and 0.04 day -1 . Laboratory observations were compared with adult growth performances in the field in two sets of experiments: the first with three contrasting populations, the second with seven full-sib families within a population. Significant differences in P productivity (growth rate per unit P in the plant) and in maximal relative growth rate were observed in both experiments, but correlation with adult performances was restricted to populations. Selection for nutrient-related traits would thus be possible, but understanding of the relationship between growth and nutrition needs further evaluation. The minimum P concentration in the seedlings supporting maximum growth ([P]optimum) varied from 2.2 to 3.8 mg g -1 DM, which is in agreement with values obtained in other species. The root/shoot ratio increased with P limitation, with a marked tendency for the population with the highest adult height performance. Inversely, within families, seedlings identified as the best performers for adult growth invested more biomass in shoots than in roots with P stress. [ABSTRACT FROM AUTHOR]

It is possible to predict the water content (6%–32%) of pine seeds — single seeds at 30 degree-days and bulk samples at 45 degree-days — using multivariate calibration models based on the near infrared (NIR) spectra (1100–2200 nm) of the seeds. One would expect the water peaks in the NIR spectra to contribute uniquely to the models, but this is not entirely the case. Different ways of studying models and spectra reveal that the contribution of the spectral information to the calibration models is complicated and nonlinear. Model parameters also show contributions from the biological processes in the seeds. Regression models between water content and NIR spectra using biorthogonal partial least squares (BPLS) showed that water content was associated with overtones of H–O–H, mainly around the peak of water at 1930–1940 nm, as expected. However, overtones of C–H, C=O, and N–H also influenced the BPLS models. This was caused by evolving biological phenomena, such as respiration and protein metabolism in imbibed seeds, and hence gave more complex regression models of seed–water interaction. There was also a difference in N–H absorption that indicated enhanced protein metabolism at prolonged degree-days. [ABSTRACT FROM AUTHOR]

Six-month-old Japanese black pine seedlings (Pinus thunbergii) were exposed to simulated acid rain (SAR) at pH 3 and 2 three times a week. After treatment for 2 months, the seedlings were inoculated with a virulent isolate (S10) of the pinewood nematode (Bursaphelenchusxylophilus), at three inoculum levels (Pi = 50, 160 or 500 nematodes per seedling). In seedlings inoculated with 500 nematodes, both population growth of nematodes and disease development were accelerated by pretreatment with SAR at pH 3 or 2. In seedlings inoculated with 50 nematodes, population growth of the nematodes was suppressed and more time was needed for seedlings to die when pretreated with pH 3 SAR. This suggests that exposure to pH 3 SAR increased not only the progress of mortality, but also simultaneously enhanced the tolerance limit of the seedlings to the pinewood nematode– the critical value of physiological burden (represented as a product of time and initial nematode population) necessary to kill a seedling. Exposure to pH 2 SAR accelerated nematode reproduction in seedlings and increased seedling mortality irrespective of the number of nematodes inoculated. [ABSTRACT FROM AUTHOR]

Examines the effects of both seedling quality and outplanting density on the performance of loblolly pine in Alabama. Impact of stocking and stock type on stand development; Economic incentives for outplanting morphologically improve seedlings; Holistic approach when comparing the costs and benefits of outplanting morphologically improved seedlings.

The abiotic environment often influences the ways in which animals interact. By affecting the cues associated with buried seeds, the type of substrate used by seed-caching rodents may alter the relative probabilities of cache pilferage and cache retrieval. We predicted that, after a wildfire, the presence of ash would impair rodents' ability to smell pine seeds on the forest floor. In a laboratory experiment, we compared the foraging success, caching frequency, and cache recovery of chipmunks (six Tamias amoenus and six T. quadrimaculatus) in ash versus sand substrates. Initial results supported our hypothesis: chipmunks found only 2.3% of 108 caches of Jeffrey pine (Pinus jeffreyi) seeds that we buried in ash but found 98% of caches in sand. However, chipmunks made as many or more of their own caches in ash compared with sand (48% for T. amoenus, 73% for T. quadrimaculatus.) When foraging for seeds cached in ash by themselves and by other individuals, they found significantly higher proportions of their own caches (62%) than of caches made by others (25%). However, when foraging in sand, they found high proportions both of their own caches and those of others (86 versus 81%). These results suggest that olfaction is less effective in ash than in sand, that spatial memory enables chipmunks to recover their own caches in ash, and that caching in ash may allow animals to avoid pilferage of stored food. As chipmunks are important dispersers of seeds, changes in their foraging patterns or competitive interactions after fire could significantly affect pine regeneration. [ABSTRACT FROM AUTHOR]

The growth cessation of plant axis has been related with the formation of diphenyl bridges among the pectic components of the cell wall caused by the action of apoplastic peroxidases using hydrogen peroxide as electron acceptor. The formation of diphenyl bridges is prevented by the presence of ascorbate in the apoplastic fluid which acts as a hydrogen peroxide scavenger. The current work focuses on the role of the apoplastic ascorbate and hydrogen peroxide in the cell growth. The addition of hydrogen peroxide caused an inhibition of the auxin-induced growth as well as a significant decrease in the cell wall creep induced by acid-pH solutions. The hydrogen peroxide content in apoplastic fluid increased with the hypocotyl age and along the hypocotyl axis of 10-day-old pine seedlings, as the growth capacity decreased. On the other hand, the ascorbate content in the apoplastic fluid decreased with the hypocotyl age and along the hypocotyl axis of 10-day-old seedlings. A very significant correlation between the hydrogen peroxide apoplastic level and the growth rate as well as between the ascorbate/hydrogen peroxide molar ratio and the growth rate of hypocotyls have been found suggesting that the redox state is the main factor controlling the cell wall stiffening mechanism and thus growth in pine hypocotyls. [ABSTRACT FROM AUTHOR]

The effects of the expected increase in growing season temperature on the performance of the aphid Schizolachnus pineti (Fabricius) (Homoptera: Lachnidae) and on the nutritional quality of its host plant (Pinus sylvestris L.) were studied under a daytime temperature range of 20–28 °C, with nighttime temperature that was either fixed at 12 °C or 8 °C below the daytime temperature. Fecundity had a curvilinear response, with an optimum at 24 or 26 °C, which is 4 to 6 °C above the local mean daytime temperatures. Longevity of nymphal stage was negatively and linearly correlated (r2 = 0.967) with daytime temperature. Intrinsic rate of population increase (rm) and relative growth rate were significantly higher at 26 °C than at 20 °C. Fecundity and rm were negatively correlated with total phenolic concentration in needles. Temperature affected concentrations of some individual resin acids in needles and stems, while concentrations of monoterpenes, total phenolics, starch, and total nitrogen in needles were not affected by temperature. Seedlings grown at 24 °C achieved the greatest biomass. Results support the protein competition hypothesis, which predicts no changes in the concentration of plant phenolics with small temperature increases. However, at 26 °C the low starch/nitrogen ratio and low total phenolic concentration may partly explain increased fecundity of aphids. [ABSTRACT FROM AUTHOR]

When conventional RNA isolation methods optimized for pine seedlings are applied to needles of adult pine trees, poor-quality RNA results. Here we describe a modified procedure to isolate high-quality RNA from needles of 30-year-old maritime pines, exhibiting high levels of phenolics, polysaccharides, and RNases. Major changes are the inclusion of proteinase K in the extraction medium followed by incubation at 42°C. Integrity and purity were evaluated by using denaturing gel electrophoresis and spectrophotometry (A260/A230 and A260/A280). The total RNA could be successfully used for poly(A)+-RNA isolation and cDNA library construction. [ABSTRACT FROM AUTHOR]

The seed-dispersal systems of Coulter pine (Pinus coulteri), gray pine (P. sabiniana), and Torrey pine (P. torreyana), all of the subsection Sabinianae, are not well understood. These pines occur in arid and semi-arid foothills and mountains of California that are subjected to frequent fires. Cone and seed traits of these three California pines are compared to those of four species of pines (sugar pine, P. lambertiana; Jeffrey pine, P. jeffreyi; ponderosa pine, P. ponderosa; and lodgepole pine, P. contorta) that occur in more mesic environments in the nearby Sierra Nevada mountains. The cones of the Sabinianae pines are large with thick, dense scales, and the scales of gray and Coulter pines are armed with sharp, recurved spines. The seeds of all three species are large, and those of gray and Torrey pines are nearly wingless. In contrast, the Sierra Nevada pines have small to medium-sized seeds with large wings that are initially dispersed by the wind. Heavy wing loading of the Sabinianae pine seeds causes them to fall rapidly, and they are not dispersed far by wind. However, animals remove the fallen seeds rapidly, and rodents and jays scatter hoarded many seeds in the soil. This caching activity results in seedling establishment. The unusual morphology of the cones and seeds of the Sabinianae pines is interpreted as a combination of traits that attract animal dispersers, thwart the foraging activities of seed predators, and promote the survival of seeds in an environment subject to frequent fires. [ABSTRACT FROM AUTHOR]

Direct seeding of Pinus sylvestris (L.) is a regeneration method of increasing popularity due to its comparatively low cost and potential for mechanisation. There is, however, a concern that seed losses to predators may jeopardise some seeding operations and means of reducing losses are therefore sought. In a study in northern Sweden, we studied the effect of covering seeds with a thin layer of the substrate on which the seeds were sown immediately after seeding. This lowered seed-predation from 9.1 to 2.9% and total seed losses from 64 to 45%. More seeds, 40% compared to 27%, failed to germinate when covered. At the end of the first growing season, 15.4% of the initially covered seeds were present as live seedlings compared to 9.2% of the seeds in the uncovered control treatment. However, although the trend remained the same, this effect was no longer significant after the first winter. The seedlings from the covered seeds were significantly larger, even after the second growing season. A complementary laboratory experiment showed that bank-voles, Clethrionomys glareolus, consumed significantly more seeds on the soil surface compared to covered seeds, but that they could find covered seeds with relative ease. We conclude that covering seeds immediately after seeding is a cost-effective way to reduce seed-predation and increase seedling emergence. [Copyright &y& Elsevier]

Colorless, euhedral crystals were abundant on the roots of chlorotic pine seedlings from one nursery in Georgia and one in Alabama in 1998. Energy dispersive spectroscopy indicated these crystals were rich in calcium (Ca) and sulfur (S), and single crystal x-ray diffraction determined the crystals to be CaSO[sub 4]·2H[sub 2]O (gypsum). These crystals had formed on the roots where water moved from the soil into the seedlings to be transpired. No records were found of gypsum crystals on the roots of living plants. Drought conditions appear to be necessary for these crystals to form in humid regions and no economic impact beyond that of the drought was indicated. [ABSTRACT FROM AUTHOR]

Evaluates the possible carry-over of seeds from common shrub and vine competitors of loblolly and shortleaf pines. Competitors of the regeneration of the pines; Germination testing of the seeds; Reliance of some species of shrubs on seeds dispersed shortly before or after the disturbance.

Investigates the pollen dynamics in an operational lodgepole pine seed orchard. Use of chloroplast DNA (cpDNA) markers in the evaluation of pollen dynamics; Attainment of high levels of cpDNA differentiation; Methods used in the attainment of the differentiation levels.