Pinus Rigida Mill Research Articles

GENETIC DIVERSITY AND POPULATION STRUCTURE IN PITCH PINE (PINUS RIGIDA MILL.).

Electrophoretic studies of protein polymorphisms in plants have focused upon herbaceous species, primarily inbreeding annuals, in efforts to characterize the levels and patterns of genic variation within and between populations (Clegg and Allard, 1972; Gottlieb, 1973, 1975; Levin, 1975, 1978; Levy and Levin, 1975; Schaal, 1975; Roose and Gottlieb, 1976; Brown et al., 1978; and others). These studies have indicated that predominantly outbreeding species maintain higher levels of intrapopulation variation than predominantly inbreeding species, while inbreeders exhibit a greater degree of population differentiation than outbreeders (Brown, 1979; Hamrick et al., 1979). This relationship is by no means perfect as Levin (1978) points out, because of differences in ecological requirements, breeding systems, dispersal mechanisms, evolutionary history, and other factors which affect the genetic system (Grant, 1958, 1971; Brown, 1979; Hamrick et al., 1979). Whether longlived perennials such as forest trees conform to the general pattern is still an open question. Allozyme studies of forest tree species have suggested that levels of genic variation are exceptionally high in natural populations (Tigerstedt, 1973; Rudin et al., 1974; Lundkvist and Rudin, 1977; Yang et al., 1977; Hamrick, 1979; Hamrick et al., 1979; Lundkvist, 1979), that certain populations appear to be moderately inbred (Rudin et al., 1974; Mejnartowicz and Bergmann, 1975; Phillips and Brown, 1977), and that populations have become differentiated over relatively short distances (Sakai and Park, 1971; Mitton et al., 1977). However, many inferences have been drawn from only one or a few loci, or only from loci known to be highly polymorphic. Valid estimates of mating system parameters may be obtained by examining only a few loci, but for estimates of heterozygosity, genic diversity, and the extent of differentiation, a large number of loci is preferred (Lewontin, 1974; Nei, 1975). As part of a continuing study of the genetics and ecology of pitch pine (Pinus rigida Mill.), we have surveyed 21 enzymatic loci in 11 populations across the species range. Pitch pine occurs from coastal Maine and southern Quebec to northern Georgia and from the Atlantic Coast to central Ohio, but almost always on relatively infertile sites. In spite of a history of overexploitation, it appears to have retained appreciable variation (Ledig and Fryer, 1974). Pitch pine demonstrates clinal patterns of variation in cone serotiny (Ledig and Fryer, 1972), wood properties (Ledig et al., 1975), and seedling growth (Ledig et al., 1976), as well as seed and needle characters (Ledig, unpubl.). It is uncertain whether these clinal patterns are the result of gene flow among pockets of differential fitness or reflect a continuous gradient in selection pressures (Endler, 1977; Givnish, 1981). The objectives of the present study were to determine the levels of genic diversity characteristic of pitch pine, and to examine the organization of genic variability within the species and the patterning of genic differentiation between populations. Among other comparisons, we contrasted marginal vs. central populations and the

Gypsy Moth in New Jersey Pine-Oak

Abstract Several pine-oak stands in southern New Jersey were defoliated by the gypsy moth, Lymantria dispar (L.). during both 1972 and 1973. Oaks were much more heavily defoliated than pines. Pinus rigida Mill. and P. echinata Mill. Radial growth among the oaks was sharply reduced during and immediately following the outbreak. Pine growth did not appear to be affected during the outbreak, and it increased sharply during the immediate three-year postoutbreak period.

Density, Age Structure, Biomass and Net Annual Aboveground Productivity of Dwarfed Pinus rigida Mill. from the New Jersey Pine Barren Plains

Density, Age Structure, Biomass and Net Annual Aboveground Productivity of Dwarfed Pinus rigida Mill. from the New Jersey Pine Barren Plains

Essential oils IV. Composition of the volatile leaf (needle) oils of Pinus species

Summary The volatile leaf (needle) oils of Pinus strobus L., Pinus rigida Mill. , and Pinus virginiana Mill. were analysed by gas chromatography — mass spectrometry (GC-MS) with the aim of characterising their mono and sesquiterpene compositions, α- and β-pinene, myrcene, car-3-ene, limonene and terpinolene were the major monoterpene hydrocarbons identified in the oils with the occurrence of α-terpineol, bornyl acetate and α-terpinyl acetate in small but varying amounts. The sesquiterpene composition comprised of caryophyllene, humulene, β-bisabolene, γ-muurolene, δ-cadinene, α-bisabolol, α- and δ-cadinol. In P. strobus and P. virginiana , the sesquiterpenes were (quantitatively) the major terpenes (71.8%, 60.2%) while in P. rigida , the monoterpenes amounted to 54.9 %. The terpene composition of the volatile leaf oil of P. strobus differed considerably from that reported previously for the same species and the needle oils of P. rigida and P. virginiana are being analysed for the first time. The biogenetic and chemosystematic significance of these results are briefly discussed.

A megagametophyte analysis of genetic linkage in pitch pine (Pinus rigida mill.)

The haploid state of conifer megagametophyte tissue provides a means of testing for genetic linkage among allozyme loci in conifers. Using pitch pine trees (Pinus rigida Mill.), which were previously determined to be heterozygous for certain allozymes, we have been able to detect linkage among several pairs of loci. One such pair, GOT-1 and GPI-2, is tightly linked showing a recombination frequency of 4 per cent. Four other pairs appear to be linked with recombination frequencies at the margin of detectability, 38–40 per cent, but tree-to-tree variation makes positive determination difficult for less tightly linked loci. Such variation may be due to small sample sizes and presence of inversion polymorphisms. These results are the first report of tight linkage in a forest tree and represent a start in mapping the conifer genome.

The Effects of Temperature Treatment on Photosynthesis of Pitch Pine from Northern and Southern Latitudes

Pitch pine (Pinus rigida Mill.) seedlings were grown at constant temperatures of either 21 C or 29 C. Photosynthetic temperature and light response curves were determined after 59, 107, and 153 days. Rates of CO2 uptake decreased with age, and the response to changes in light and temperature became less pronounced. Growth temperatures had no effect on the photosynthetic temperature optimum, and populations from Quebec, New Jersey, and Tennessee all had the same temperature optimum and response pattern. For the Tennessee population, growth at 21 C depressed the rate of photosynthesis at all temperatures at both 59 and 107 days, but stimulated it at 153 days. The Quebec population showed no effect of premeasurement temperature at 59 or 153 days, and the New Jersey population was intermediate in this respect. Photosynthetic plasticity, defined as the difference between photosynthetic rates of seedlings grown at 21 C and those grown at 29 C, was related inversely to the degree of seasonal variation under which the populations had evolved.

Maintenance and Constructive Respiration, Photosynthesis, and Net Assimilation Rate in Seedlings of Pitch Pine (Pinus rigida Mill.)

Maintenance and Constructive Respiration, Photosynthesis, and Net Assimilation Rate in Seedlings of Pitch Pine (Pinus rigida Mill.)

Growth Characteristics of Two Populations of Pinus rigida Mill. from the Pine Barrens of New Jersey

The Outer Coastal Plain of New Jersey is largely dominated by pitch pine (Pinus rigida) forests. Most of the area supports trees of normal stature (Barrens) but fairly extensive areas of pygmy forest (Plains) also are present. We compared germination and growth characteristics of two populations representing these types. Seeds derived from trees of the contrasting forms were grown under greenhouse—nursery and phytotron conditions for periods up to 5 1/2 yr. Height, growth form, and biomass comparisons were made. Significant height differnces were found in both studies while significant biomass differences were found primarily in the greenhouse—nursery study. Where significant differences existed, Plains progeny were shorter and lighter than their Barrens counterparts. Height and biomass differences were greater in older plants but statistical differences were present in seedlings < 1 yr old. Plains progeny also included a larger percentage of poor, shrubby growth forms and were markedly more precocious in regard to cone productin. We conclude that inherent characteristics of Plains trees, whether physiological or genetic, contribute in part to the stunted nature of the Plains.

Dimension and Production Relations of Trees and Shrubs in the Brookhaven Forest, New York

Extensive tracts of oak-pine forest grow on the level, sandy soils of glacial outwash derivation on Long Island, New York (Conard 1935). The forests are small and unimpressive to a forester. In mature stands older and larger pines (Pinus rigida Mill.) rise above a canopy of oaks (Quercus alba L., Q. coccinea Muench, and few Q. velutina Lam. and other species). The canopy is open, with light intensity below the trees sufficient to support a shrub stratum of small Vacciniaceae of high coverage (Reiners 1965). These forests are floristically related to the pine forests of New Jersey and the Coastal Plain southward, and to the pine heaths of the Great Smoky Mountains (Whittaker 1956), with which they share a number of major species. All of these forests have been subject to repeated fires, and dense, immature successional stands with Pinus rigida and scrub oak (Qtiercus ilicifolia Wang.) occur over extensive areas. The small size of the trees at Brookhaven has facilitated development of a system of detailed dimension analysis useful for various problems related to forest volume, biomass, production, surface and nutrient circulation. The methods are developments from forest measurements used by Burger (1929, 1953), Boysen Jensen (1932), Moller (1945, 1947), Ovington (1957), Ovington & Madgwick (1959a, b) and others, but are intended to advance beyond those measurements in important respects. They use the wood rings and bud-scale scars which mark annual increments of growth in some climates for assessment of current net production and nutrient movement in forests. They are designed specifically to deal with the complexities of many-aged stands including climaxes, as distinguished from plantations. The work is part of a long-term study of various aspects of the Brookhaven forest as an ecosystem, a study which includes experimental irradiation of a segment of the forest with gamma radiation from a cesium soturce (Woodwell 1962, 1965). The plants of the present study have been taken from the forest outside the area of radiation effects. Included in this report are results of dimension analysis of trees and shrubs as a first phase of the research on bio mass, production and nutrient circulation.

Effects of chronic exposures to Co 60 radiation on Pinus rigida seedlings

An experiment was designed to test effects of differential exposures to ionizing radiations at various stages of development and periods of growth on the survival, height growth, productivity, and cytology of Pinus rigida Mill, seedlings. Seedlings were exposed to radiation at 9 levels (0–20 R/20 hr day) in the Gamma Field at the Brookhaven National Laboratory, Upton, New York. Treatment consisted of transferring seedlings from each exposure level in the Gamma Field to a control field at various times of the year. This resulted in 5 groups of seedlings of different durations of exposure (156–485 days) at all levels. Radiation had a marked effect on terminal shoot growth inhibition and in the stimulation of sprouting. Shoot growth decreased, and flushing was delayed with increasing exposure, while sprouting increased. Sprouting was responsible for the survival of many of the seedlings. Increased exposure to radiation also resulted in a decrease in subterminal bud formation and, at the higher levels (15 and 20 R/day), no axial primordia developed and the apical primordia were damaged. Needle length decreased with increasing exposure but cell damage in the needle meristems was slight. Two microsporangiate strobili were produced in 1 month on a sprout from a seedling that had been exposed to a total of 6800 R at a rate of 20 R/day, representing a considerable shortening of the normal phenology. Observations of sprouting in the spring of 1963 showed that in seedlings exposed to higher levels of radiation, sprouting was suppressed, probably as a result of the general weakening of the plants. Stem sprouting was inhibited to a greater extent than was basal sprouting. Basal sprouting was probably the result of partial shielding of the root collars by soil.

The relationship of the sterols of the Virginia pine sawfly, Neodiprion pratti Dyar, to those of two host plants, Pinus virginiana Mill and Pinus rigida Mill

Approximately one-tenth per cent of the wet weight of Neodiprion pratti larvae is composed of sterols of which 73 per cent is cholesterol, 6 per cent is 7-dehydrocholesterol, 4 per cent is campesterol, and 17 per cent β-sitosterol. The sterol composition of the foliage of two host plants was as follows: Pinus virginiana—β-sitosterol (92 per cent), campesterol (7 per cent), and ‘cholesterol’ (<1 per cent), and Pinus rigida—β-sitosterol (94 per cent) and campesterol (6 per cent). No larval biosynthesis of sterols from 14C-labelled acetate, mevalonate, or glucose was apparent. The sawfly dealkylates the phytosterols to cholesterol and presumably obtains its required cholesterol in this manner.

Germination of Pinus rigida seeds after gamma irradiation : Effects of post-irradiation treatments, moisture content and individual trees

The effects of environmental factors, particularly moisture content and storage treatment, on responses to gamma irradiation were studied in seeds of Pinus rigida Mill. The variable germination results obtained with commercially purchased seed indicated a need for close control of conditions before and during experiments. Techniques were developed for uniform collection and treatment of seeds from trees growing in the natural pitch pine-oak forest at the Brookhaven National Laboratory, Upton, New York. To study the effect of exposure rate and post-irradiation treatment on germination, samples of seeds were exposed to ten total exposures (0–48 kr) at two exposure periods (16 and 80 hr). After irradiation, seeds were either sown immediately or stored for four weeks at 4 °G under dry or moist conditions. Moist stratification caused an increase in germination that was paralleled by a decrease in cytological damage at all exposure levels, but there was no difference between the exposure periods within any post-irradiation treatment. The nature of recovery after irradiation was studied using a 16-hr exposure period, five total exposures (0–24 kr) and six stratification periods (0–6 weeks). Stratification decreased the radiation effect, and the recovery period at lower levels of radiation was shorter than at higher levels. Stratification increased germination at all radiation levels but not the rate of seedling development. Samples were equilibrated for eight days at six moisture contents (2·4–16·1%) and exposed for 16 hr to five exposures (4·36 kr). Increased moisture content up to 8·9% decreased the radiosensitivity, and between 10·9 and 16·1%, LD 60 values for germination were similar (20–21 kr). In this range there was no loss of germination capacity up to 12 kr, although seedling development was retarded. Recovery increased with increasing stratification period and moisture content. Using a 16-hr exposure period and a total exposure of 5 kr, there were significant differences in seed germination between ten trees and within individual trees. Seeds from the upper crown were generally more sensitive to gamma rays than those from lower positions. The variation in radiosensitivity was not related to differences in seed size. Throughout the paper, the LD 50 values that are reported deal with germination percentages.

Nutrient Utilization by Young Pitch Pine

AbstractTen pitch pines (Pinus rigida Mill.) ranging in age from 5 to 9 years were excavated from an abandoned gravel pit in southern New Jersey. Lateral and vertical distribution of the root systems were recorded and total soil volume occupied by roots was calculated (root system sorption zone). In addition, the volume of soil within 1 cm. of any root surface was calculated (root surface sorption zone). Contents of total and exchangeable Ca and K in these zones were related to contents of Ca and K in the trees. Exchangeable Ca and K contents in the root system sorption zone were generally higher than the total content of these nutrients in the trees while the reverse was true for the relationship between the root surface sorption zone and the tree. Annual uptake of K by the trees was approximately equal to exchangeable K content of the root surface sorption zone. Annual uptake of Ca by trees was only about one‐third of the exchangeable Ca in the root surface sorption zone indicating that average distance of movement of Ca from soil to root surface was less than that for K. Less than 10% of the total soil volume occupied by roots was utilized in absorption of Ca and K.

THE LARVA AND PUPA OF HERCULIA INTERMEDIALIS WLK. (PYRALIDAE, LEPIDOPTERA)

Three specimens of the last instar larva of Herculia intermedialis Wlk. were collected in the debris of sawdust, spider silk, etc. accumulated under a loose piece of bark on the trunk of a standing pine (Pinus rigida Mill.). These hibernating larvae were taken at Buzzards Bay, Mass., on the nineteenth of April. When disturbed the larvae wriggled backwards and dropped to the ground on a thread of silk. Prior to pupation, which occurred April 21, the caterpillars ate a quantity of bark and rotten wood. Just what their true food is remains to be discovered.

Further Studies on Cold Resistance in Evergreens, with Special Reference to the Possible Role of Bound Water

1. Seasonal variations in the cold resistance of the leaves of evergreen species are discussed in terms of the present knowledge of such phenomena. Evergreen leaves, in general, are not cold-resistant during the warmer months of the year. Time and temperature factors involved in the hardening of the leaves of such species are analyzed in terms of known facts. The work of several investigators indicates that the threshold temperature for hardening seems to be about +6⚬ C. A few hours' exposure to this or a lower temperature per day suffices to keep the leaves in the hardened condition. During warm spells in the winter the leaves of some species of plants seem to lose their hardiness very quickly; in other species the physiological changes causing loss of hardiness appear to occur much more slowly. 2. In this investigation attention was directed to further studies bearing on the hypothesis that an increase in bound water is an important factor in the cold resistance of the leaves of evergreen species. A pressure dehydration method of distinguishing between bound and free water in plant tissues is outlined. A modified form of the calorimetric procedure of determining the amount of free water in a system, suitable for use with plant tissues, is described. An improved form of the equation for calculating the amount of free water from the calorimetric data is also derived. 3. The leaves of the pitch pine (Pinus rigida Mill.) were used as the material for investigation. The total amount of water in the leaves of this species was about 5 per cent less in the winter as compared with the summer. Larger amounts of sap can be expressed from these leaves in the summer than in the winter, but this difference represents almost entirely a correlation with the difference in total water content. No evidence could be obtained by the pressure dehydration method of any significant increase in the amount of bound water in the pine leaf tissues in the winter as compared with the summer. The calorimetric determinations showed greater amounts of both bound and free water per gram of dry matter in the leaves of this species in the summer as compared with the winter. The differences between the summer and winter values were statistically significant. Apparently, as has been found previously in nonliving colloidal systems, there is a positive correlation between the total hydration of the tissues and the amounts of both bound and free water per gram of dry matter. No evidence was obtained, therefore, that increase in bound water plays any role in the cold resistance of this species. 4. The results of other investigations are critically analyzed in relation to the results of this investigation. It is suggested that the basis for cold resistance lies in some as yet not understood physicochemical properties of the protoplasm, which probably cannot be discovered by the gross measurements which are generally employed at present.

Two New Species of Rusts

On a collecting trip at Takoma Park, Maryland, with Dr. G. G. Hedgcock, a caeoma-like species of Peridermium was collected on Pinus rigida Mill. which proved to be Peridermium delicatulum Arth. & Kern. Later, in looking over the species of Periderniuml in the Pathological Collections of the United States Department of Agriculture, hoping to find other collections of this rare species, the writer found a specimen on Pinus virginianla Mill., which from its gross characters appeared to be Peridernmiuml delicatulum, but a microscopic examination showed it to be an undescribed species. On a trip made during I9II through some of the forests of Arizona and new Mexico, the writer while descending the Santa Catalina Mountains found, on Coulrsetia glandulosa Gray, a rust which on microscopic examination proved to be an undescribed species intermediate in its generic position between Phragmopy.is Dietel and Calliospora Arth. Technical descriptions of these two fungi are given below.