Seasonal dynamics of non-structural carbon pools and their relationship to growth in two boreal conifer tree species

2021 ◽  
Author(s):  
A S Schoonmaker ◽  
R Hillabrand ◽  
V J Lieffers ◽  
P S Chow ◽  
S M Landhäusser

Abstract In an attempt to comprehensively study the dynamics of non-structural carbon compounds (NCC), we measured the seasonal changes of soluble sugars, starch, lipids, and sugar alcohols in the leaves, branches, stem, and roots of the fast-growing Pinus contorta (pine) and slow-growing Picea glauca (spruce) trees growing in a boreal climate. In addition to measuring seasonal concentrations of these compounds, the relative contribution of these compounds to the total NCC pool within organs of trees (~8 m tall) was estimated and compared across different phenological and growth stages. Both species showed large seasonal shifts from starch to sugars from spring to fall in nearly all organs and tissues; most likely an adaptation to the cold winters. For both species the total fluctuation of sugar + starch across the year (i.e., the difference between the minimum and maximum observed across collection times) was estimated to be between 1.6 kg and 1.8 kg for all NCCs. The fluctuation, however, was 1.40 times greater than the minimum reserves in pine while only 0.72 times the minimum reserves in spruce. By tissue type, NCC fluctuations were greatest in the roots of both species. Roots showed a large build-up of reserves in late spring, but these reserves were depleted over summer and fall. Storage reserves in needles and branches declined over the summer and this decline may be linked to the sink strength of the stem during diameter growth. Some notable highlights of this holistic study: a late winter build-up of sugars in the stem xylem of both species but especially spruce; an increase in sugar alcohols in the bark of spruce in very late winter which could indicate mobilization to support early growth in spring; high lipid reserves in the bark of pine, that appeared not to be impacted by seasonal changes between summer and winter. Collectively, these observations point towards a more conservative NCC reserve strategy in spruce compared to pine which is consistent with its stress tolerance and greater longevity.

Weed Science ◽  
2021 ◽  
pp. 1-23
Author(s):  
Katherine M. Ghantous ◽  
Hilary A. Sandler

Abstract Applying control measures when carbohydrate levels are low can decrease the likelihood of plant survival, but little is known about the carbohydrate cycles of dewberry (Rubus spp.), a problematic weed group on cranberry farms. Weedy Rubus plants were collected from areas adjacent to production beds on commercial cranberry farms in Massachusetts, two locations per year for two years. For each site and year, four entire plants were collected at five phenological stages: budbreak, full leaf expansion, flowering, fruit maturity, and after onset of dormancy. Root sections were analyzed for total nonstructural carbohydrate (TNC; starch, sucrose, fructose, and glucose). Overall trends for all sites and years showed TNC were lowest at full leaf expansion or flowering; when sampled at dormancy, TNC concentrations were greater than or equal to those measured at budbreak. Starch, a carbohydrate form associated with long-term storage, had low levels at budbreak, leaf expansion and/or flowering with a significant increase at fruit maturity and the onset of dormancy, ending at levels higher than those found at budbreak. The concentration of soluble sugars, carbohydrate forms readily usable by plants, was highest at budbreak compared to the other four phenological samplings. Overall, our findings supported the hypothesis that TNC levels within the roots of weedy Rubus plants can be predicted based on different phenological growth stages in Massachusetts. However, recommendations for timing management practices cannot be based on TNC cycles alone; other factors such as temporal proximity to dormancy may also impact Rubus plants recovery and further research is warranted. Late-season damage should allow less time for plants to replenish carbohydrate reserves (prior to the onset of dormancy), thereby likely enhancing weed management tactics effectiveness over time. Future studies should consider tracking the relationship between environmental conditions, phenological stages, and carbohydrate trends.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259585
Author(s):  
Gull Mehak ◽  
Nudrat Aisha Akram ◽  
Muhammad Ashraf ◽  
Prashant Kaushik ◽  
Mohamed A. El-Sheikh ◽  
...  

Optimum water availability at different growth stages is one the major prerequisites of best growth and yield production of plants. Exogenous application of plant growth regulators considered effective for normal functioning of plants under water-deficit conditions. A study was conducted to examine the influence of exogenously applied L-methionine on sunflower (Helianthus annuus L.) plants grown under water-deficit conditions. Twenty-five-day old seedlings of four sunflower cultivars, FH331, FH572, FH652 and FH623 were exposed to control (100% F.C.) and drought stress (60% F.C.) conditions. After 30-day of drought stress, L-methionine (Met; 20 mg/L) was applied as a foliar spray to control and drought stressed plants. Water deficit stress significantly reduced shoot fresh and dry weights shoot and root lengths, and chlorophyll a content in all four cultivars. While a significant increase was observed due to water deficiency in relative membrane permeability (RMP), malondialdehyde (MDA), total soluble proteins (TSP), total soluble sugars (TSS), ascorbic acid (AsA) and activity of peroxidase (POD). Although, exogenously applied Met was effective in decreasing RMP, MDA and H2O2 contents, it increased the shoot fresh weight, shoot length, chlorophyll a, chlorophyll a/b ratio, proline contents and the activities of SOD, POD and CAT enzymes in all four cultivars under water deficit stress. No change in AsA and total phenolics was observed due to foliar-applied Met under water stress conditions. Of all sunflower cultivars, cv. FH-572 was the highest and cv. FH-652 the lowest of all four cultivars in shoot fresh and dry weights as well as shoot length under drought stress conditions. Overall, foliar applied L-methionine was effective in improving the drought stress tolerance of sunflower plants that was found to be positively associated with Met induced improved growth attributes and reduced RMP, MDA and H2O2 contents under water deficit conditions.


HortScience ◽  
2019 ◽  
Vol 54 (12) ◽  
pp. 2169-2177 ◽  
Author(s):  
Karen Mesa ◽  
Sara Serra ◽  
Andrea Masia ◽  
Federico Gagliardi ◽  
Daniele Bucci ◽  
...  

Annual accumulation of starch is affected by carbon reserves stored in the organs during the growing season and is controlled mainly by sink strength gradients within the tree. However, unfavorable environmental conditions (e.g., hail events) or application of management practices (e.g., defoliation to enhance overcolor in bicolor apple) could influence the allocation of storage carbohydrates. This preliminary research was conducted to determine the effects of early defoliation on the dry matter, starch, and soluble carbohydrate dynamics in woody organs, roots, and mixed buds classified by age and two levels of crop-load for one growing season in ‘Abbé Fétel’ pear trees (Oct. 2012 to mid-Jan. 2013 in the northern hemisphere). Regardless of the organs evaluated (woody organs, roots, and mixed buds), an increase of soluble carbohydrate concentration was observed in these organs in the period between after harvest (October) and January (dormancy period). Among all organs, woody short-old spurs showed the highest increase (+93.5%) in soluble sugars. With respect to starch, woody organs showed a clear trend of decreasing in concentration between October and January. In this case, short-old spurs showed the smallest decline in starch concentrations, only 6.5%, whereas in other tree organs starch decreased by 34.5%. After harvest (October), leaves showed substantially higher starch and soluble sugar concentrations in trees with lower crop-loads. These results confirm that in the period between October and January, dynamic interconversions between starch and soluble carbohydrates occur at varying magnitudes among organs in pear trees.


2010 ◽  
Vol 86 (1) ◽  
pp. 118-129 ◽  
Author(s):  
M J Waterhouse ◽  
E. C. Wallich ◽  
N. M. Daintith ◽  
H. M. Armleder

Mature lodgepole pine (Pinus contorta) forests were harvested using group selection (GS) (0.02-ha openings) and irregular group shelterwood (IGS) (0.05-ha openings) systems to maintain arboreal and terrestrial lichens in the winter range of northern woodland caribou (Rangifer tarandus caribou). Ten years after planting, lodgepole pine showed excellent survival, but were smaller in the partial cut openings compared to the clearcuts. Pine grew less in the Sub-Boreal Pine–Spruce biogeoclimatic subzone (SBPSxc) than in the Montane Spruce subzone (MSxv), and trees were smaller in the GS versus IGS treatment within the MSxv subzone. Interior spruce (Picea glauca × engelmannii) grew best in the MSxv and partial cut treatments, but was significantly affected by summer frost in the clearcuts. In an operational-scale Adaptive Management trial, openings were enlarged to 0.15 ha, and both pine and spruce showed excellent survival, minimal frost damage, and 10-year size similar to clearcut conditions. This study suggests that lodgepole pine and interior spruce can be successfully regenerated in partial cut openings with acceptable growth in gaps of 0.15 ha. Key words: caribou, group selection, interior spruce, irregular group shelterwood, light level, lodgepole pine, Montane Spruce zone, partial harvest, soil moisture, soil temperature, Sub-Boreal Pine Spruce zone, summer frost


1995 ◽  
Vol 46 (6) ◽  
pp. 1273 ◽  
Author(s):  
SM Rhind ◽  
SR McMillen

In a 2 x 2 factorial experiment, seasonal changes in hormone and insulin-like growth factor-1 (IGF-1) profiles were compared in goats of two genotypes (Siberian (S) and Icelandic x Scottish feral (IF); n = 20 per genotype) with differing patterns of secondary fibre growth. Half of the goats of each genotype were fed rations containing either 100 or 180 g crude protein (CP)/kg dry matter. The period of secondary fibre growth was longer and the rate of growth greater in S than IF goats, but there were no effects of dietary protein concentration. Mean plasma concentrations of insulin, cortisol, T3 and T4 were higher in winter and those of prolactin, GH and IGF-1 concentrations were higher in summer. Growth of secondary fibre in S goats between January and March was associated with higher plasma prolactin and lower plasma insulin concentrations at this time than in IF goats in which there was no secondary fibre growth. The observed genotypic differences in times of onset and cessation of fibre growth were not associated with differences in the times of seasonal changes in any of the other hormones measured, and there was no effect of dietary protein level on hormone profiles. The higher mean growth rate and greater diameter of secondary fibre in S goats was associated with higher mean concentrations of T4 than in IF goats, throughout the study. Four S goats which exhibited secondary fibre growth during the summer had higher (P < 0.05) mean plasma insulin concentrations than other animals of that genotype. It is suggested that genotypic differences in prolactin concentrations in late winter/spring may affect the time of onset of secondary fibre growth and that the cessation of growth may be influenced by differences in the timing of the seasonal decline of circulating prolactin concentrations to basal levels. However, the maintenance of relatively high plasma insulin concentrations may prolong growth in some circumstances. The higher concentrations of T4 in S than IF goats may have a role in the enhancement of the rate of fibre growth in these animals. The onset of moult in both genotypes was associated with the spring increase in plasma prolactin concentrations.


2017 ◽  
Vol 47 (8) ◽  
pp. 1116-1122 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Qing-Lai Dang

Conifer winter damage results primarily from loss of cold hardiness during unseasonably warm days in late winter and early spring, and such damage may increase in frequency and severity under a warming climate. In this study, the dehardening dynamics of lodgepole pine (Pinus contorta Dougl. ex. Loud), jack pine (Pinus banksiana Lamb.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) were examined in relation to thermal accumulation during artificial dehardening in winter (December) and spring (March) using relative electrolyte leakage and visual assessment of pine needles and spruce shoots. Results indicated that all four species dehardened at a similar rate and to a similar extent, despite considerably different thermal accumulation requirements. Spring dehardening was comparatively faster, with black spruce slightly hardier than the other conifers at the late stage of spring dehardening. The difference, however, was relatively small and did not afford black spruce significant protection during seedling freezing tests prior to budbreak in late March and early May. The dehardening curves and models developed in this study may serve as a tool to predict cold hardiness by temperature and to understand the potential risks of conifer cold injury during warming–freezing events prior to budbreak.


2020 ◽  
Author(s):  
Séverine A. E. Boyer ◽  
Jean‐Marc Haudin ◽  
Vivian Song ◽  
Vincent Bourassier ◽  
Patrick Navard ◽  
...  

1991 ◽  
Vol 6 (3) ◽  
pp. 64-67 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Wayne L. Martin

Abstract The incidence of meadow vole (Microtus pennsylvanicus) and brown lemming (Lemmus sibiricus) feeding damage to young plantations of lodgepole pine (Pinus contorta var. latifolia) and interior spruce (Picea glauca × Picea engelmannii) was studied in west-central British Columbia. Fifty-eight plantations were surveyed for seedling survival and stocking, and an additional 21 older plantations of lodgepole pine were surveyed for tree damage. Average survival of pine (47.7%) was significantly lower than that of spruce (56.0%). Because of mortality from vole feeding, 24 of the 58 plantations were not satisfactorily restocked. Planted trees were attacked significantly more than natural regeneration. Severely attacked plantations occurred in the spruce-subalpine fir (Abies lasiocarpa) forest type at elevations > 800 m on N to NE aspects. Susceptible plantations generally had mechanical or no site preparation with complex post-harvest debris and limited vegetation cover. West. J. Appl. For. 6(3):64-67.


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