Needle dark respiration in relation to within-crown position in Scots pine trees grown in long-term elevation of CO2 concentration and temperature

2002 ◽  
Vol 156 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Tianshan Zha ◽  
Kai-Yun Wang ◽  
Aija Ryyppo ◽  
Seppo Kellomaki
The Holocene ◽  
2021 ◽  
pp. 095968362199465
Author(s):  
Dael Sassoon ◽  
William J Fletcher ◽  
Alastair Hotchkiss ◽  
Fern Owen ◽  
Liting Feng

Around 4000 cal yr BP, Scots pine ( Pinus sylvestris) suffered a widespread demise across the British Isles. This paper presents new information about P. sylvestris populations found in the Welsh Marches (western central Britain), for which the long-term history and origins are poorly known. Two new pollen records were produced from the Lin Can Moss ombrotrophic bog (LM18) and the Breidden Hill pond (BH18). The LM18 peat core is supported by loss-on-ignition, humification analysis and radiocarbon dating. Lead concentrations were used to provide an estimated timeframe for the recent BH18 record. In contrast to many other Holocene pollen records from the British Isles, analysis of LM18 reveals that Scots pine grains were deposited continuously between c. 6900–300 cal yr BP, at frequencies of 0.3–5.4%. It is possible that individual Scots pine trees persisted through the wider demise on thin soils of steep drought-prone crags of hills or the fringes of lowland bogs in the Welsh Marches. At BH18, the record indicates a transition from broadleaved to mixed woodland, including conifer species introduced around AD 1850 including Picea and Pinus. The insights from BH18 suggest that the current populations may largely be the result of planting. Comparison of the LM18 findings with other regional pollen records highlights consistent patterns, including a Mid-Holocene maximum (ca. 7000 cal yr BP), long-term persistence at low pollen percentages and a Late-Holocene minimum (ca. 3000 cal yr BP). These distinctive trends encourage further studies on refugial areas for Scots pine in this region and elsewhere.


2020 ◽  
Author(s):  
Zsofia R. Stangl ◽  
Lasse Tarvainen ◽  
Mats Räntfors ◽  
Göran Wallin ◽  
John D. Marshall

<p><span>Global models of photosynthesis commonly use photosynthetic capacity parameters (V<sub>cmax</sub>, J<sub>max</sub>) that are estimated based on C<sub>i</sub>, the intercellular CO<sub>2</sub> concentration. The underlying assumption of these models is that mesophyll conductance (gm) is infinite and therefore the CO<sub>2</sub> concentration at the site of carboxylation (C<sub>c</sub>) is equal to C<sub>i</sub>, despite a growing body of literature acknowledging that these assumptions are incorrect. Because relatively few studies on gm have been conducted under natural conditions and with high enough resolution, it is currently unclear how significant the assumption of infinite C<sub>c</sub> is for the accuracy of long-term predictions by large-scale photosynthesis models. In this study we investigated this question with data collected in a mature Scots pine stand, one of the dominant species of the boreal region. We conducted high-resolution gas-exchange and online <sup>13</sup>C discrimination measurements over a whole growing season (May-October), and analysed the relative contribution of diffusional and biochemical limitations to photosynthesis. We hypothesised that diffusional limitation will be significant in this species, as conifers typically have low stomatal and mesophyll conductance (g<sub>s</sub> and g<sub>m</sub> respectively). Accordingly, we found that diffusional limitations were similar or stronger than biochemical limitation during May-July, and that all limitations reached minima around the end of June when A<sub>net</sub> values were highest. However, during August-October biochemical limitation became increasingly dominant, as the diffusional limitations were relatively small and stable. Over the whole period, both g<sub>m</sub> and the relative mesophyll limitation were similar in magnitude to g<sub>s</sub> and the stomatal limitation, respectively, resulting in a 40-100 ppm reduction in CO2 concentration between C<sub>i</sub> and C<sub>c</sub>. This meant that V<sub>cmax</sub> was under-estimated by 20-40% when calculated from C<sub>i</sub>compared to C<sub>c</sub>, highlighting the importance of accounting for the finite g<sub>m </sub>when determining photosynthetic capacity and modelling photosynthesis under natural conditions.</span></p>


HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 851-855
Author(s):  
Ming Li ◽  
Wei-tang Song

Long-term exposure to an elevated ambient carbon dioxide (eCO2) concentration could weaken or diminish the enhancement of plant photosynthesis and growth. To monitor this response and offer references for growth management, the whole-plant photosynthetic rate (Pn,w) and dark respiration rate (Rd,w) of Angelica acutiloba Kitagawa transplants were monitored with a growth chamber. The results showed that eCO2 increased both the Pn,w and Rd,w by (79 ± 42) % and (126 ± 51) %. The dry weight of transplants under eCO2 was 33.6% greater than that under aCO2. However, the photosynthetic acclimation to eCO2 occurred. The increase in the Pn,w was maintained until the end of the experiment due to increased leaf area. Moreover, the increase in plant dry weight mainly occurred in the first 15 days of treatment. Furthermore, the dry weight estimated based on the Pn,w and Rd,w agreed well with the measured dry weight. The relative growth rate (RGR) calculated with the estimated dry weight demonstrated the response of transplant growth to eCO2. These results indicated that the proposed method can be used to monitor the response of plant growth to eCO2.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Michelle Nordkvist ◽  
Maartje J. Klapwijk ◽  
La rs Edenius ◽  
Christer Björkman

AbstractMost plants are subjected to damage from multiple species of herbivores, and the combined impact on plant growth can be non-additive. Since plant response to herbivores tends to be species specific, and change with repeated damage, the outcome likely depend on the sequence and number of attacks. There is a high likelihood of non-additive effects on plant growth by damage from mammals and insects, as mammalian herbivory can alter insect herbivore damage levels, yet few studies have explored this. We report the growth response of young Scots pine trees to sequential mammal and insect herbivory, varying the sequence and number of damage events, using an ungulate-pine-sawfly system. Combined sawfly and ungulate herbivory had both additive and non-additive effects on pine growth—the growth response depended on the combination of ungulate browsing and sawfly defoliation (significant interaction effect). Repeated sawfly herbivory reduced growth (compared to single defoliation) on un-browsed trees. However, on browsed trees, depending on when sawfly defoliation was combined with browsing, trees exposed to repeated sawfly herbivory had both higher, lower and the same growth as trees exposed to a single defoliation event. We conclude that the sequence of attacks by multiple herbivores determine plant growth response.


1991 ◽  
Vol 27 (1) ◽  
pp. 89-93 ◽  
Author(s):  
Tero Kuoksa ◽  
Anja Hohtola
Keyword(s):  

2011 ◽  
Vol 9 (2) ◽  
pp. 272-275 ◽  
Author(s):  
Albina R. Franco ◽  
Carla Santos ◽  
Mariana Roriz ◽  
Rui Rodrigues ◽  
Marta R. M. Lima ◽  
...  

Pine wilt disease, caused by the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, is originating severe infections in pine trees. The disease is detected when external symptoms appear (e.g. needle chlorosis), but trees could remain asymptomatic for long periods and serve as a long-term host. The primary goal of this study was to assess the effect of inoculation with an avirulent isolate of B. xylophilus (C14-5) on different Pinus spp. seedlings (P. sylvestris, P. nigra, P. pinea and P. pinaster). At the same time, seedlings were also inoculated with a virulent strain, HF, in order to compare the phenotypic and genomic results of the two types of inoculations. The effect of inoculation was determined in terms of expression of various Pinus genes potentially involved in the response to the disease.The results suggest that P. pinea and P. nigra are more resistant to infection by the nematode than P. sylvestris and P. pinaster. The phenotypic and genetic differences were more marked among P. pinea and P. pinaster.


2015 ◽  
Vol 40 (3) ◽  
pp. 186-190 ◽  
Author(s):  
A. V. Timokhina ◽  
A. S. Prokushkin ◽  
A. A. Onuchin ◽  
A. V. Panov ◽  
G. B. Kofman ◽  
...  

Author(s):  
А.В. Лебедев ◽  
В.В. Кузьмичев

Сосна обыкновенная является одной из основных лесообразующих пород Европы, а ее древесина находит широкое применение в лесопромышленном комплексе. При оценке углерододепонирующих функций считается, что конверсионные коэффициенты являются константными по времени. Последние исследования показывают, что происходящие климатические изменения оказывают существенное влияние на прирост древесины и ее свойства. Цель данного исследования – выявление долговременных тенденций в изменении биомассы фракций деревьев сосны обыкновенной в Европе, происходящих с 1940 г. Для проверки гипотезы о влиянии календарного года на биомассу фракций деревьев проводился регрессионный анализ с применением линейных моделей смешанных эффектов. Проведенный статистический анализ позволил выявить достоверное влияние (при p < 0,05) календарного года только на биомассу стволов в коре. Наиболее сильно изменения проявляются для деревьев в молодняках и средневозрастных насаждениях, где происходит формирование наибольшего радиального прироста. Для крупномерных стволов, согласно результатам моделирования, снижение биомассы стволов в коре не прослеживается. В ближайшие десятилетия в результате продолжающихся климатических изменений процесс снижения биомассы и плотности древесины крупномерных стволов должен усилиться. Выявленные изменения биомассы сопровождаются снижением плотности древесины, что происходит в результате увеличения в структуре годичного прироста более рыхлой и менее плотной ранней древесины. Таким образом, в условиях ускоряющихся темпов роста древесных растений объемы стволов и запасы древесины не должны напрямую пересчитываться в депонированный углерод с учетом исторических значений конверсионных коэффициентов. Это также следует учитывать при мониторинге, моделировании и использовании углерода и биомассы в лесах в условиях глобальных изменений. Scots pine is one of the main forest-forming species in Europe, and its wood is widely used in the timber industry. When evaluating carbon-depositing functions, the conversion rations are assumed to be constant over time. Recent studies show that the ongoing climatic changes have a significant impact on the growth of trees and wood properties. Therefore, the purpose of this study is to identify long-term trends in the change in the biomass of Scots pine tree fractions in Europe since 1940. To test the hypothesis about the influence of the calendar year on the biomass of tree fractions, regression analysis was performed using linear mixed-effect models. The performed statistically analysis made it possible to reveal a significant effect (p < 0.05) of the calendar year only on the biomass of the trunks in the bark. The changes are most pronounced for trees in young and middle-aged stands, where the formation of the greatest radial growth occurs. For large-sized trunks, according to the simulation results, the biomass of the stems in the bark is not traced. In the coming decades, as a result of ongoing climate change, the decline in biomass and wood density of largesized stems should intensify. The revealed changes in biomass are accompanied by a decrease in wood density, which occurs as a result of an increase in the structure of the annual growth of looser and less dense early wood. Thus, in the context of accelerating growth rates of woody plants, the volume of trunks and wood stock should not be directly converted into deposited carbon, considering the historical values of conversion rations. This should also be considered when monitoring, modeling and using carbon and biomass in forests in the face of global change.


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