scholarly journals Provenance Variation in Early Survival, Growth, and Carbon Isotope Discrimination of Southwestern Ponderosa Pine Growing in Three Common Gardens across an Elevational Gradient

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1561
Author(s):  
Aalap Dixit ◽  
Thomas Kolb ◽  
Owen Burney ◽  
Karen Mock ◽  
Kevin Grady
Keyword(s):  
Growth Rate ◽  
Carbon Isotope ◽  
Ponderosa Pine ◽  
Carbon Isotope Discrimination ◽  
Elevational Gradient ◽  
High Elevation ◽  
Provenance Variation ◽  
Isotope Discrimination ◽  
Common Gardens ◽  
High Elevation Site

We investigated early survival, growth, and carbon isotope discrimination of ponderosa pine (Pinus ponderosa Lawson & C. Lawson var. scopulorum Engelm.) seedlings from different provenances using common gardens across an elevational gradient in order to examine the potential for adaptation to extreme environments and constraints to artificial regeneration. Twenty-one provenances from a range of elevations across Arizona and New Mexico were planted in three common gardens: a high-elevation meadow in aspen-mixed conifer forest, a mid-elevation ponderosa pine forest, and a low-elevation pinyon juniper woodland. Two years after planting in 2018, survival was highest at the mid-elevation site (54%), low at the high-elevation site (1.5%), and 0% at the low-elevation site. At the hot and dry low-elevation site, provenances from low-elevations survived longer than provenances from mid- and high-elevations, which suggests greater drought tolerance of low-elevation provenances. Mortality agents changed from abiotic (drought) to biotic (herbivory) with an increase in elevation across sites. High mortality of seedlings planted at high-elevation sites from biotic agents, such as rodents, may challenge efforts to establish ponderosa pine in assisted migration projects. Seedlings had significantly higher growth rate and carbon isotope discrimination (∆13C) at the mid-elevation site than the high-elevation site. Provenances differed significantly in diameter, and ∆13C, but not in height growth rate for the first year after planting. Provenance variation in ∆13C suggests genetic variation in water use efficiency that may be useful for future evaluation of southwestern ponderosa pine seed sources for reforestation.

scholarly journals Provenance Geographical and Climatic Characteristics Influence Budburst Phenology of Southwestern Ponderosa Pine Seedlings

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1067
Author(s):  
Aalap Dixit ◽  
Thomas Kolb ◽  
Owen Burney
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Common Garden ◽  
Elevational Gradient ◽  
High Elevation ◽  
Mean Annual Precipitation ◽  
Positive Trend ◽  
Provenance Variation ◽  
Pine Seedlings ◽  
Budburst Phenology

Ponderosa pine (Pinus ponderosa Lawson & C. Lawson var. scopulorum Engelm.) forests of the southwestern US are threatened by climate change and deforestation. Information about geographic patterns of provenance variation in budburst phenology is needed to make decisions about selecting seed sources for future planting. In this study, provenance variation in the budburst phenology of ponderosa pine seedlings was examined using common garden studies. Seedlings from 21 provenances, representing an elevational gradient in Arizona and New Mexico, were planted in July 2018 at a ponderosa pine-dominated field site in northern Arizona. Field budburst was monitored weekly on all seedlings in the spring of 2019. Field budburst was compared with budburst timing of the same provenances measured under greenhouse conditions. The hypotheses for this study were that (1) budburst varies among provenances, with earlier budburst in low-elevation provenances, and (2) differences in budburst timing among provenances are consistent for seedlings grown in greenhouse and field environments. Field results show that provenances vary in budburst date and that low- and middle-elevation provenances break bud sooner than high-elevation provenances. Field budburst date had a moderate, positive correlation with provenance mean annual precipitation (r = 0.522) and a moderate, negative trend with latitude (r = −0.413). Budburst date of provenances in the greenhouse had a moderate, positive trend with budburst date in the field (r = 0.554), suggesting application of greenhouse results to field plantings. Such information about provenance variation and environmental and geographic trends in budburst timing will be useful for developing species-specific seed transfer guidelines and effective assisted migration strategies in a changing climate.

Genotypic Variation in Relative Growth Rate and Carbon Isotope Discrimination in Sunflower Is Related to Photosynthetic Capacity

1996 ◽  
Vol 23 (2) ◽  
pp. 227 ◽  
Author(s):  
JM Virgona ◽  
DG Farquhar
Keyword(s):  
Growth Rate ◽  
Carbon Isotope ◽  
Relative Growth Rate ◽  
Carbon Isotope Discrimination ◽  
Photosynthetic Capacity ◽  
Genotypic Variation ◽  
Wild Accession ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Isotope Discrimination

A previous study showed that carbon isotope discrimination (Δ) was negatively related to transpiration efficiency (W, the ratio of dry matter accumulation to transpiration) and biomass accumulation amongst sunflower (Helianthus annuus L.) genotypes. Three experiments which explore the physiological basis of relationships between Δ, relative growth rate (RGR) and leaf gas exchange characteristics are reported. Growth was analysed on seven genotypes during the early vegetative stage (up to 31 days after emergence). Carbon isotope discrimination, Δ, W, and photosynthetic CO2 assimilation rate per unit leaf area (A) at ambient concentration of CO2 were measured on plants that made up the final harvest. Six of the seven genotypes were also grown under a low nitrogen (N) regime and harvested at 30 days after emergence. Carbon isotope discrimination was negatively related to relative growth rate (RGR), net assimilation rate (NAR) and photosynthetic rate per unit area, which in turn, were all positively correlated with each other. Genotypic variation inA (51%) was greater than that in leaf conductance, g (32%) and there was no relationship between g and Δ. Under the low N regime, A and g declined by 33 and 12%, respectively, across all genotypes producing a significant rise in A of 1.10. In a second experiment, growth analysis on 13 cultivated forms of H. annuus, a wild accession and a H. argophyllus accession, also showed that there was a positive relationship between RGR and NAR, and that both growth indices were negatively related to Δ. In a further experiment, using 14 genotypes (including the wild accession) there was a highly significant negative correlation (r = -0.85, P < 0.001) between photosynthetic capacity, measured using an oxygen electrode, and Δ. These results indicate that variation in photosynthetic capacity can account for genotypic variation in both Δ and RGR during vegetative growth in sunflower. Hence, faster growing sunflower genotypes have higher rates of photosynthesis and use water more efficiently.

Provenance variation in carbon isotope discrimination of mature ponderosa pine trees at two locations in the Great Plains

2000 ◽  
Vol 30 (3) ◽  
pp. 428-439 ◽  
Author(s):  
Bert M Cregg ◽  
J Miguel Olivas-García ◽  
Thomas C Hennessey
Keyword(s):  
New Mexico ◽  
Carbon Isotope ◽  
Ponderosa Pine ◽  
Carbon Isotope Discrimination ◽  
Genotypic Variation ◽  
Environment Interaction ◽  
Isotope Discrimination ◽  
Seed Sources ◽  
Genotype Environment Interaction ◽  
Use Efficiency

We analyzed genotypic variation in carbon isotope discrimination (Δ), photosynthetic gas exchange, and needle morphology of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) trees from four seed sources growing in two 26-year-old provenance plantings near Plattsmouth, Neb., and Norman, Okla. The populations studied were from South Dakota, New Mexico, Wyoming, and Nebraska. Net photosynthesis (A) and needle conductance to water vapor (gwv), were measured during the growing season of 1994. Specific leaf area, stomatal density, and Δ were analyzed in needles grown from 1991 to 1994. The southernmost source (New Mexico) had the highest intrinsic water-use efficiency (A/gwv) among the sources studied. Carbon isotope discrimination was correlated with growth (r = -0.81, P < 0.05), A/gwv (r < -0.54, P < 0.001), and gwv (r > 0.46, P < 0.05) but not A. Variation in Δ was significant among seed sources and years (P < 0.001). We observed a strong genotype × environment interaction in Δ resulting from geographic location but not moisture availability within locations. We hypothesize that the genotype × environment interaction is related to variation in growth phenology among the seed sources. Improving water-use efficiency or growth of ponderosa pine via Δ will require an understanding in genotypic variation in growth rhythms.

Genotypic variation in carbon isotope discrimination and gas exchange of ponderosa pine seedlings under two levels of water stress

2000 ◽  
Vol 30 (10) ◽  
pp. 1581-1590 ◽  
Author(s):  
J Miguel Olivas-García ◽  
Bert M Cregg ◽  
Thomas C Hennessey
Keyword(s):  
New Mexico ◽  
Water Stress ◽  
Gas Exchange ◽  
Carbon Isotope ◽  
Ponderosa Pine ◽  
Carbon Isotope Discrimination ◽  
Seed Source ◽  
Isotope Discrimination ◽  
Seed Sources ◽  
Moisture Availability

As part of a program to select ponderosa pine (Pinus ponderosa Dougl. ex Laws.) genotypes for improved drought tolerance, we examined physiological and morphological characteristics of 12 half-sib families of ponderosa pine from four seed sources; New Mexico, South Dakota, Nebraska, and Wyoming. We analyzed genetic variation in carbon isotope discrimination (Δ), photosynthetic gas exchange, needle morphology, and growth of 2-year-old seedlings from the four seed sources grown under two levels of moisture availability. To gain a better understanding of within-provenance variation and identify opportunities to refine selection strategies, we also examined family within seed source variation in the traits. Water stress significantly (P < 0.05) reduced net photosynthesis (A), needle conductance to water vapor (gwv), carbon isotope discrimination (Δ), and growth of the seedlings as compared to well-watered seedlings. However, instantaneous water use efficiency (A/gwv) did not differ between water treatments. Seedlings from New Mexico had significantly lower gwv and higher A/gwv than seedlings from the other sources. Carbon isotope discrimination was lowest for seedlings from New Mexico and Nebraska. Families within seed sources varied significantly in A, gwv, stomatal density, needle length, height increment, and Δ. Carbon isotope discrimination was significantly correlated with gwv but not with A, supporting results from mature trees suggesting that variation in Δ in ponderosa pine is more related to gwv than to A. Seed source × water treatment interactions were not observed for any of the traits analyzed. These results support our previous assertion that genotype × environment interaction in Δ of mature ponderosa pine trees from these sources grown in Nebraska and Oklahoma was related to factors other than moisture availability.

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