Global climate change and tree nutrition: effects of elevated CO2 and temperature

Although tree nutrition has not been the primary focus of large climate change experiments on trees, we are beginning to understand its links to elevated atmospheric CO2 and temperature changes. This review focuses on the major nutrients, namely N and P, and deals with the effects of climate change on the processes that alter their cycling and availability. Current knowledge regarding biotic and abiotic agents of weathering, mobilization and immobilization of these elements will be discussed. To date, controlled environment studies have identified possible effects of climate change on tree nutrition. Only some of these findings, however, were verified in ecosystem scale experiments. Moreover, to be able to predict future effects of climate change on tree nutrition at this scale, we need to progress from studying effects of single factors to analysing interactions between factors such as elevated CO2, temperature or water availability

Leaf- and plant-level carbon gain in yellow birch, sugar maple, and beech seedlings from contrasting forest litght environments

Leaf-level photosynthetic-light response and plant-level daily carbon gain were estimated for seedlings of moderately shade-tolerant yellow birch (Betula alleghaniensis Britton) and shade-tolerant sugar maple (Acer saccharum Marsh.) and beech (Fagus grandifolia Ehrh.) growing in gaps and under a closed canopy in a sugar maple stand at Duchesnay, Que. All three species had a higher photosynthetic capacity (A(max)) in the gaps than in shade, but yellow birch and beech responded more markedly than sugar maple to the increase in light availability. The high degree of plasticity observed in beech suggests that the prediction that photosynthetic plasticity should decrease with increasing shade tolerance may not hold when comparisons are made among a few late-successional species. Unit-area daily carbon gain (C(A)) was significantly higher in the gaps than in shade for all three species, but no significant difference was observed between light environments for plant-level carbon gain (C(W)). In shade, we found no difference of C(A) and C(W) among species. In gaps, beech had a significantly higher C(A) than sugar maple but similar to that of birch, and birch had a significantly higher C(W) than maple but similar to that of beech. Sugar maple consistently had lower carbon gains than yellow birch and beech but is nevertheless the dominant species at our study site. These results indicate that although plant-level carbon gain is presumably more closely related to growth and survival of a species than leaf-level photosynthesis, it is still many steps removed from the ecological success of a species

Linking ethylene to nitrogen-dependent leaf longevity of grass species in a temperate steppe

Author's manuscript made available in accordance with the publisher's policy.Background and Aims Leaf longevity is an important plant functional trait that often varies with soil nitrogen supply. Ethylene is a classical plant hormone involved in the control of senescence and abscission, but its role in nitrogen-dependent leaf longevity is largely unknown. Methods Pot and field experiments were performed to examine the effects of nitrogen addition on leaf longevity and ethylene production in two dominant plant species, Agropyron cristatum and Stipa krylovii, in a temperate steppe in northern China. Key Results Nitrogen addition increased leaf ethylene production and nitrogen concentration but shortened leaf longevity; the addition of cobalt chloride, an ethylene biosynthesis inhibitor, reduced leaf nitrogen concentration and increased leaf longevity. Path analysis indicated that nitrogen addition reduced leaf longevity mainly through altering leaf ethylene production. Conclusions These findings provide the first experimental evidence in support of the involvement of ethylene in nitrogen-induced decrease in leaf longevity

The successional status of tropical rainforest tree species is associated with differences in leaf carbon isotope discrimination and functional traits

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Spatial and temporal variations in the photosynthesis-nitrogen relationship in a Japanese cedar (Cryptomeria japonica D. Don) canopy

The original publication is available at www.springerlink.comSpatial and temporal variations in light-saturated photosynthetic capacity and needle nitrogen (N) content were investigated in one 8 m tall Japanese cedar (Cryptomeria japonica D. Don) canopy for a full year. The photosynthetic capacity and needle N content in various layers of the canopy were measured every month. Temporal variations in photosynthetic capacity and needle N content expressed on a projected-area basis (P-area, N-area) were similar. Furthermore, both P-area and N-area decreased with increasing depth from the top of the canopy on each sampling date. As a consequence, a significant correlation was observed between N-area and P-area. Temporal variations in photosynthetic capacity and needle N content expressed on a mass basis (P-mass, N-mass) were also similar. P-mass also decreased with increasing canopy depth. However, in contrast to N-area, there was only a slight decrease in N-mass with increasing canopy depth. Hence, the correlation between N-mass and P-mass was lower than the projected-area value. Because N-area was highly correlated with the needle mass per projected-area (NMA), the spatial variation in N-area (and therefore P-area) in the canopy is attributed to the variation in NMA, which decreases as the depth from the top of the canopy increases. Furthermore, the slope of the linear regression between N-area and NMA differed between sampling dates, indicating that the temporal variations in N-area (and therefore P-area) are strongly influenced by N-mass. For most of the sampling dates, a linear regression between N-area and P-area tends to converge into a single line segment. However, on several sampling dates, there was a pronounced decline in P-area below this line segment. This reduction in P-area, which does not accompany a reduction in Narea, seems to be attributable to stomatal limitations induced by the low soil temperature in winter and early spring.ArticlePHOTOSYNTHETICA. 48(2): 249-249(2010)journal articl

Seasonal changes in photosynthesis of eight savanna tree species

Seasonal variations in carbon assimilation of eight tree species of a north Australian tropical savanna were examined over two wet seasons and one dry season (18 months). Assimilation rates (A) in the two evergreen species, Eucalyptus tetrodonta F. Muell. and E. miniata A. Cunn. ex Schauer, were high throughout the study although there was a 10-20% decline in the dry season compared with the wet season. The three semi-deciduous species (Erythrophleum chlorostachys (F. Muell.) Baillon, Eucalyptus clavigera A. Cunn. ex Schauer, and Xanthostemon paradoxus F. Muell.) showed a 25-75% decline in A in the dry season compared with the wet season, and the deciduous species (Terminalia ferdinandiana Excell, Planchonia careya (F. Muell.) Kunth, and Cochlospermum fraseri Planchon) were leafless for several months in the dry season. Generally, the ratio of intercellular CO2 concentration to ambient CO2 concentration (C(i):C(a)) was larger in the wet season than in the dry season, indicating a smaller stomatal limitation of photosynthesis in the wet season compared with the dry season. In all species, the C(i):C(a) ratio and A were essentially independent of leaf-to-air vapor pressure difference (LAVPD) during the wet season, but both parameters generally declined with increasing LAVPD in the dry season. The slope of the positive correlation between A and transpiration rate (E) was less in the wet season than in the dry season. There was no evidence that high E inhibited A. Instantaneous transpiration efficiency was lowest in the wet season and highest during the dry season. Nitrogen-use efficiency (NUE) was higher in the wet season than in the dry season because the decline in A in the dry season was proportionally larger than the decline in foliar nitrogen content. In the wet season, evergreen species exhibited higher NUE than semi-deciduous and deciduous species. In all species, A was linearly correlated with specific leaf area (SLA) and foliar N content. Foliar N content increased with increasing SLA. All species showed a decline in midday leaf water potential as the dry season progressed. Dry season midday water potentials were lowest in semi-deciduous species and highest in the deciduous species, with evergreen species exhibiting intermediate values

Temperate and tropical forest canopies are already functioning beyond their thermal thresholds for photosynthesis

Tropical tree species have evolved under very narrow temperature ranges compared to temperate forest species. Studies suggest that tropical trees may be more vulnerable to continued warming compared to temperate species, as tropical trees have shown declines in growth and photosynthesis at elevated temperatures. However, regional and global vegetation models lack the data needed to accurately represent such physiological responses to increased temperatures, especially for tropical forests. To address this need, we compared instantaneous photosynthetic temperature responses of mature canopy foliage, leaf temperatures, and air temperatures across vertical canopy gradients in three forest types: tropical wet, tropical moist, and temperate deciduous. Temperatures at which maximum photosynthesis occurred were greater in the tropical forests canopies than the temperate canopy (30 ± 0.3 °C vs. 27 ± 0.4 °C). However, contrary to expectations that tropical species would be functioning closer to threshold temperatures, photosynthetic temperature optima was exceeded by maximum daily leaf temperatures, resulting in sub-optimal rates of carbon assimilation for much of the day, especially in upper canopy foliage (\u3e10 m). If trees are unable to thermally acclimate to projected elevated temperatures, these forests may shift from net carbon sinks to sources, with potentially dire implications to climate feedbacks and forest community composition

이산화탄소 폭로 처리에 따른 질소 제한 환경 하에서 임목의 광합성과 질소 분배 반응

학위논문 (석사)-- 서울대학교 대학원 : 농업생명과학대학 산림과학부(산림환경학전공), 2019. 2. 김현석.증가된 대기 중 이산화탄소는 생리적 특성인 광합성률, 기공전도도 변화 뿐 아니라 잎과 줄기의 바이오매스 증가와 같은 형태적 특성 또한 변화시킨다. 고농도의 이산화탄소하에서 순일차생산량이 증가할 것으로 예상되었으나 질소가 제한된 환경에서는 광합성 저감으로 인해 초기생장을 유지하지 못하게 되는 결과를 가져오게 된다. 질소는 식물 생장의 제한요소로서 잎 질소의 대부분은 광합성 및 기능적 기관에 투자되어 있으며 이러한 질소분배는 수관, 수종, 환경에 따라 변화하며 광합성 질소이용효율에 영향을 끼치게 된다. 본 연구는 장기간 상부개방형 온실을 이용하여 이산화탄소 농도 변화로 인한 제한된 질소 환경에서 소나무(Pinus densiflora), 물푸레나무(Fraxinus rhynchophylla), 팥배나무(Sorbus alnifolia)의 광합성 특성 및 질소분배 특성 변화를 알아보고자하였다. 최근 2년간 온실 간 직경생장량 차이가 나타나지 않았으나 잎 크기와 엽중량비(leaf mass per area) C:N비와 같은 형태적 인자는 대조구에 비해 고농도의 이산화탄소 온실인 챔버1.4와 1.8에서 높았다. 광합성 인자의 경우, 최대광합성 속도는 챔버1.4와 1.8에서 대조구에 비해 증가하였으며, 특히 물푸레나무에서 유의하게 증가하였다. 반면 광합성 능력인 최대카르복실화 속도(VCmax)와 최대전자전달속도(Jmax)는 챔버1.8에서 감소하였다. 토양질소 분석 결과, 토양 전질소 함량은 챔버 간 차이가 발생하지 않았으며, 토양 무기태 질소 또한 별다른 차이를 보이지 않았다. 광합성 능력의 감소는 이산화탄소 증가에 따른 엽면적의 증가로 인한 단위질량당 잎 질소 감소에 의해 발생하며 본 연구결과에서도 모든 수종에서 대조구에 비해 챔버1.4와 1.8에서 유의하게 감소하였다. 반면 단위면적 당 잎 질소함량은 처리구간 차이가 나타나지 않았다. 단위 질량당 잎 질소함량의 감소로 인하여 루비스코 함량 또한 챔버1.8에서 유의하게 감소하였으나 엽록소 질소 햠량은 이산화탄소 농도가 증가할수록 증가하였으며 엽록소에 투자된 질소비율 또한 유의하게 증가하였다. 수관별 분석결과에서는 수관하부에 비해 수관상부의 루비스코 질소비율이 고농도의 이산화탄소에서 유의하게 감소하였으나 엽록소 질소비율은 모든 수관에서 이산화탄소 농도에 따른 차이가 발생하지 않았다. 본 연구결과에서 나타난 챔버1.8에서의 광합성 질소이용효율의 증가는 질소분배 특성인 세포벽 질소비율, 루비스코 질소비율과 엽록소 질소비율 중 광합성 인자인 루비스코 질소비율과 엽록소질소비율과 강한 상관관계를 보였으며 세포벽 질소비율과는 상관관계를 보이지 않았다. 따라서 고농도 이산화탄소 하에서의 엽록소 질소비율 증가로 인해 광합성 질소이용효율 증가가 나타나고, 이로 인해 광합성 특성의 감소에도 불구하고 광합성의 양의 증가와 바이오매스 생산량의 유지가 일어난다고 판단된다.Increased atmospheric CO2 concentration could mitigate the climate warming via enhanced forest productivity, which is substantially affected by nutrient availability, especially N, and its efficiency. Therefore, the changes of N concentration and its allocation in leaf under long term elevated CO2 [eCO2] exposure is important for future prediction. This study was conducted to investigate the changes of the photosynthetic characteristics and nitrogen allocation of Japanese red pine (Pinus densiflora), Korean ash (Fraxinus rhynchophylla) and Korean whitebeam (Sorbus alnifolia), which have been growing under three different CO2 concentrations (ambient [aCO2], ambient x 1.4 [eCO21.4] and ambient x 1.8 [eCO21.8]) for nine years. There was no significant difference in growth of diameter among chambers in last two years, but the morphological characteristics such as leaf size and leaf mass per area were higher at eCO2 than aCO2. In case of photosynthetic characteristics, the maximum photosynthetic rate (Amax) was higher at eCO2 than aCO2, especially in Korean ash. On the other hand, the maximum carboxylation rate (VCmax) and the maximum electron transfer rate (Jmax), decreased significantly at eCO21.8. Photosynthetic down-regulation was not caused by the decrease of leaf nitrogen per unit area (Narea), but it was rather caused by the changes in N allocation. The N allocation to Rubisco (NFRub) and cell wall (NFcw) did not change among chambers, while the nitrogen fraction to chlorophyll (NFchl) increased at eCO2 than aCO2. In addition, the changes of N allocation were species- and position-specific. The reduction of NFRub and the enhancement of NFchl were the most pronounced in Korean whitebeam. NFcw decreased significantly only in Korean ash. The decrease of NFRub in eCO2 was greater in upper canopy than in lower canopy, while the enhancement of NFchl was not different among canopy positions. The increment of NFchl increased PNUE and increased the amount of photosynthesis and maintained biomass production despite of photosynthetic capacity reduction. Our result implied the effect of elevated CO2 could last longer even with the N limitation due to the enhancement of PNUE caused by change of N allocation.Abstract ⅰ List of Tables ⅳ List of Figures ⅴ 1. Introduction 1 2. Material and Methods 4 2.1. Study sites 4 2.2. Growth of diameter at root collar (DRC) 4 2.3. Leaf gas exchange 5 2.4. Leaf sizes, leaf mass per area and nitrogen content 5 2.5. N allocation in Rubisco, chlorophyll and cell wall 6 2.6. Data analysis 7 3. Results 9 3.1. Growth of diameter at root collar 9 3.2. Leaf size, LMA 9 3.3. Photosyntheis characteristics 11 3.4. Total leaf N content and C:N ratio 15 3.5. Photosynthetic nitrogen use efficiency 19 3.6. Leaf N allocation 20 4. Discussion 28 4.1. Changes in leaf morphological characteristics and relationship with nitrogen concentration under elevated CO2 28 4.2. Changes of photosynthetic characteristics and nitrogen allocation characteristics under elevated CO2 28 4.3. Changes in nitrogen allocation characteristics under elevated CO2 and canopy position 29 4.4. Correlation between increase of PNUE and changes in nitrogen allocation characteristics under elevated CO2 30 4.5. Progressive nitrogen limitation and sustainability of forest productivity through nitrogen allocation characteristics 32 5. Conclusion 33 References 34 Abstract in Korean 40Maste

The role of plant species in biomass production and response to elevated CO 2 and N

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72902/1/j.1461-0248.2003.00467.x.pd

Relationships between leaf life span, leaf mass per area, and leaf nitrogen cause different altitudinal changes in leaf delta C-13 between deciduous and evergreen species

ArticleBOTANY-BOTANIQUE. 86(11):1233-1241 (2008)journal articl