Whole-seedling biomass allocation, leaf area, and tissue chemistry for Douglas-fir exposed to elevated CO2 and temperature for 4 years

2003 ◽  
Vol 33 (2) ◽  
pp. 269-278 ◽  
Author(s):  
David M Olszyk ◽  
Mark G Johnson ◽  
David T Tingey ◽  
Paul T Rygiewicz ◽  
Claudia Wise ◽  
...  

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown under ambient or elevated ( ambient + 180 µmol·mol–1) CO2 and ambient or elevated (ambient + 3.5°C) temperature in outdoor, sunlit chambers with a field soil. After 4 years, seedlings were harvested and measured for leaf area, leaf, fine root (<1 mm diameter), and structural (buds, branches, stems, main root, and lateral roots >1 mm in diameter) dry masses, and leaf and fine root C/N ratio, percent sugar, and percent cellulose. Elevated CO2 did not affect biomass production or allocation for any plant organ but increased specific leaf mass, leaf C/N ratio, and percent sugar and decreased the ratio of leaf area to structural weight and leaf percent cellulose. Elevated temperature tended to reduce biomass allocation to leaves and leaf sugar concentration. Fine root percent sugar tended to increase with elevated temperature but only at elevated CO2. Therefore, for Douglas-fir seedlings growing under naturally limiting soil moisture and nutrition conditions, elevated CO2 and temperature may have little impact on biomass or leaf area except for reduced specific leaf mass with elevated CO2 and reduced biomass allocation to leaves with elevated temperature. However, both elevated CO2 and temperature may alter leaf chemistry.


2006 ◽  
Vol 170 (2) ◽  
pp. 345-356 ◽  
Author(s):  
M. G. Johnson ◽  
P. T. Rygiewicz ◽  
D. T. Tingey ◽  
D. L. Phillips


2000 ◽  
Vol 27 (6) ◽  
pp. 595 ◽  
Author(s):  
Hendrik Poorter ◽  
Oscar Nagel

The allocation of biomass to different plant organs depends on species, ontogeny and on the environment experienced by the plant. In this paper we first discuss some methodological tools to describe and analyse the allocation of biomass. Rather than the use of shoot:root ratios, we plead strongly for a subdivision of biomass into at least three compartments: leaves, stems and roots. Attention is drawn to some of the disadvantages of allometry as a tool to correct for size differences between plants. Second, we tested the extent to which biomass allocation of plants follows the model of a ‘functional equilibrium’. According to this model, plants respond to a decrease in above-ground resources with increased allocation to shoots (leaves), whereas they respond to a decrease in below-ground resources with increased allocation to roots. We carried out a meta-analysis of the literature, analysing the effect of various environmental variables on the fraction of total plant biomass allocated to leaves (leaf mass fraction), stem (stem mass fraction) and roots (root mass fraction). The responses to light, nutrients and water agreed with the (qualitative) prediction of the ‘functional equilibrium’ theory. The notable exception was atmospheric CO2, which did not affect allocation when the concentration was doubled. Third, we analysed the quantitative importance of the changes in allocation compared to changes in other growth parameters, such as unit leaf rate (the net difference between carbon gain and carbon losses per unit time and leaf area), and specific leaf area (leaf area: leaf biomass). The effects of light, CO2 and water on leaf mass fractions were small compared to their effects on relative growth rate. The effects of nutrients, however, were large, suggesting that only in the case of nutrients, biomass allocation is a major factor in the response of plants to limiting resource supply.



Author(s):  
Matthias Meyer ◽  
Kristin Morgenstern ◽  
Dávid Heilig ◽  
Bálint Heil ◽  
Gábor Kovács ◽  
...  

AbstractEarly above- and belowground biomass fractionation, root diameter composition and allocation of cumulated fine root length per total leaf area of Populus clones have been measured for a pre-assessment of the risk for plantation establishment during spring drought conditions. Four clones of Populus × euramericana, and one P. nigra × P. maximowiczii clone (cv. Max 3), were planted in sandy mix substrate and were exposed to one normal and one deficit watering regime over 65-day greenhouse experiments conducted during early summer. The P. × euramericana hybrids showed plasticity of their root biomass fractions. Although clone Max 3 was among the productive clones, even under deficit watering, it was not able to respond plastically to deficit watering. It showed no increase in the root biomass fraction and no increase in the ratio of cumulated fine root length per total leaf area. Therefore, the clone Max 3 should not be planted under high risk for spring drought. Planting the investigated P. × euramericana clones under water deficit likely involves a lower risk, but clone differences within this group must be considered. It can be concluded that the water deficit response of biomass allocation to roots and of the ratio of fine root length per unit leaf area is suitable traits to improve drought risk assessments that are based on yield response of poplar clones to drought. Percent plant loss data and the yield at the end of the first SRC rotation will be suitable to verify the present greenhouse assessment.



2000 ◽  
Vol 27 (12) ◽  
pp. 1191 ◽  
Author(s):  
Hendrik Poorter ◽  
Oscar Nagel

The allocation of biomass to different plant organs depends on species, ontogeny and on the environment experienced by the plant. In this paper we first discuss some methodological tools to describe and analyse the allocation of biomass. Rather than the use of shoot:root ratios, we plead strongly for a subdivision of biomass into at least three compartments: leaves, stems and roots. Attention is drawn to some of the disadvantages of allometry as a tool to correct for size differences between plants. Second, we tested the extent to which biomass allocation of plants follows the model of a ‘functional equilibrium’. According to this model, plants respond to a decrease in above-ground resources with increased allocation to shoots (leaves), whereas they respond to a decrease in below-ground resources with increased allocation to roots. We carried out a meta-analysis of the literature, analysing the effect of various environmental variables on the fraction of total plant biomass allocated to leaves (leaf mass fraction), stem (stem mass fraction) and roots (root mass fraction). The responses to light, nutrients and water agreed with the (qualitative) prediction of the ‘functional equilibrium’ theory. The notable exception was atmospheric CO2, which did not affect allocation when the concentration was doubled. Third, we analysed the quantitative importance of the changes in allocation compared to changes in other growth parameters, such as unit leaf rate (the net difference between carbon gain and carbon losses per unit time and leaf area), and specific leaf area (leaf area: leaf biomass). The effects of light, CO2 and water on leaf mass fractions were small compared to their effects on relative growth rate. The effects of nutrients, however, were large, suggesting that only in the case of nutrients, biomass allocation is a major factor in the response of plants to limiting resource supply.



2020 ◽  
Vol 68 (3) ◽  
Author(s):  
Carolina Ramos-Montaño

ABSTRACT. Introduction: Thanks to filtration by foliage, urban trees have a crucial role in air depuration. However, the exposure to pollutants could reduce their health and physiological performance, mainly because of low access to light and clogging of stomata by particulate matter. Objective: The accumulation of particulate matter on leaves (PMAL) and physiological traits of five urban tree species (Croton bogotanus Cuatrec., Eugenia myrtifolia Sims., Ficus soatensis Dugand, Schinus mole L., and Sambucus nigra L.) were quantified in sixty points in Bogotá, with the aims to (1) build a model explaining the PMAL based on traffic variables, (2) establishing the effect of vehicle pollution on physiological and phytosanitary variables, and (3) to evaluate the susceptibility of seedlings and trees to vehicle pollution. Methods: The physiological parameters: photochemical efficiency, stomatal conductance, chlorophyll content, leaf area, and specific leaf mass were measured and correlated with phytosanitary condition, PMAL and traffic variables: number of lanes, vehicular flow and tree-to-avenue distance. Additionally, tree physiological responses were measured in control, residential streets (RS), low traffic avenues (LTA), and high traffic avenues (HTA), and these last were compared with physiology of seedlings planted by three months in HTA. Results: PMAL was strongly associated with physiological responses. Ficus soatensis and C. bogotanus were the species with the maximum and the minimum PMAL. The exposure to traffic increased the photochemical efficiency and specific leaf mass, which could be related to the enrichment of nitrogen and atmospheric CO2. The stomatal conductance followed a bell pattern of low gas exchange in control sites, high values in RS and LTA, and decreasing again in HTA, which suggests an optimization in CO2 fixation at intermediate levels of pollution and susceptibility to stomatal clogging by extreme vehicle emissions. The chlorophyll a/b ratio, leaf area, and specific leaf mass were significantly related to the severity of leaf symptoms, and S. molle was the species with the healthiest leaves in HTA. Seedlings were more susceptible to pollution than trees, and fruits size and seedlings growth were affected by vehicular pollution. Conclusions: Ficus soatensis optimizes particle filtration and C. bogotanus is ideal for planting in HTA, although only as saplings. By contrast, the fast-growing E. myrtifolia and S. nigra seedlings should not be planted in HTA because of susceptibility of pigment contents, leaf area, and stomatal conductance to pollutants. Finally, because of its persistent high stomatal conductance and its low leaf symptoms, S. molle is the species with the best adaptation to vehicle pollution. A complete analysis of interactions among traffic, physiology, and health will help to improve the urban forestry planning. 



2006 ◽  
Vol 18 (4) ◽  
pp. 455-465 ◽  
Author(s):  
Claudivan F. Lacerda ◽  
José O. Assis Júnior ◽  
Luiz C. A. Lemos Filho ◽  
Teógenes S. de Oliveira ◽  
Francisco V.A. Guimarães ◽  
...  

The effect of salt stress of known intensity and duration on morpho-physiological changes in leaves of different ages from cowpea [Vigna unguiculata (L.) Walp.] plants was studied, aiming for a better understanding of the acclimation process of the whole-plant. Seeds were sown in vermiculite and seedlings were transferred to plastic trays containing aerated nutrient solution, and kept in a greenhouse. When the first trifoliate leaf emerged the seedlings were transplanted into 3 L plastic pots containing aerated nutrient solution. Salt additions started 5 d later, and the salt-treated plants received 25 mmol L-1 per day until reaching a final concentration of 75 mmol L-1. During the experimental period primary leaves and the 1st, 2nd, and 3rd trifoliate leaves were used for measurements of net photosynthesis, leaf area, leaf succulence, specific leaf mass, ions and chlorophyll concentrations. Growth analysis of the whole-plant was performed at the end of the experimental period. Salinity did not affect net photosynthesis, but reduced dry mass production and the number of lateral branches. Leaf concentrations of Na+, Cl-, K+ and P increased in salt-stressed plants, but these responses were dependent upon stress duration and leaf age. The higher concentration of potentially toxic ions (Na+ and Cl-) in older leaves could contribute to the reduced ion accumulation in growing tissues, but the tendency of K and P accumulation in leaves appeared to be the result of reduced re-translocation, i.e., not related to plant acclimation. Salinity also increased the source/sink ratio, leaf succulence, specific leaf mass, and chlorophyll accumulation per unit of leaf area, suggesting that the observed changes could be part of an integrated mechanism of whole-plant acclimation to salt stress.



2020 ◽  
pp. 1310-1318
Author(s):  
Luis Felipe Boaretto ◽  
Fabricio Silva Coelho ◽  
João Leonardo Corte Baptistella ◽  
Paulo Mazzafera

Research on the accumulation and partitioning of biomass in the tobacco cycle is scarce, particularly those comparing different varieties. The objective of this work was to study the partition of biomass in air-cured burley - ACB (BAT2101) and flue-cured virginia - FCV (CSC4704) varieties. In a greenhouse experiment, the two varieties were transplanted into pots containing a mixture of fine sand and substrate (1:1). Samples were taken for a period of 98 days, with 7 day intervals. In each harvest, dry mass and leaf area were measured, and specific leaf mass, leaf area ratio, relative growth rate, net assimilation rate, and root to shoot ratios were estimated. The data showed that carbon partitioning in plants of both varieties is influenced by root growth, which was 50% higher in ACB by the end of the experiment. The higher accumulation of mass in the roots of this variety may be related to the fact that it requires more nitrogen than virginia and, therefore, it could be a mechanism for increased uptake of this element. ACB also had higher specific leaf mass than FCV, which may be related to the body of ACB. This information is important for choosing varieties adapted for field conditions, as well as for the genetic improvement of tobacco. Furthermore, from the point of view of crop management, this knowledge may provide useful information for maximizing leaf growth.



Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 793
Author(s):  
Yaxiong Zheng ◽  
Fengying Guan ◽  
Shaohui Fan ◽  
Yang Zhou ◽  
Xiong Jing

Functional characteristics reflect plant strategies and adaptability to the changing environment. Determining the dynamics of these characteristics after harvesting would improve the understanding of forest response strategies. Strip clearcutting (SC) of moso bamboo forests, which significantly reduces the cutting cost, has been proposed to replace manual selective harvesting. A comparison of restoration features shows that 8 m is the optimal cutting width. However, the precise response of functional features to the resulting harvest-created gap remains unclear. In this study, three SC plots were selected which was performed in February 2019, with three unharvested plots as a control (C). The study focused on 10 functional traits, including leaf area (LA), specific leaf area (SLA), leaf dry matter content (LDMC), leaf nitrogen content (LNC), leaf phosphorus content (LPC), nitrogen/phosphorus ratio (N:P), wood density (WD), fine root biomass (FRB), specific fine root length (SRL), and root length density (RLD). A one-way ANOVA was used to compare differences in functional traits and soil nutrients between treatments. Strip clearcutting significantly reduced the soil organic carbon (SOC) and total nitrogen (TN) contents (p < 0.05). In terms of functional characteristics, SC significantly decreased LA and increased LNC, LPC, and N:P (p < 0.05). However, SC had no significant effect on fine root traits (p > 0.05). This study highlighted that root trait, soil content of total phosphorus (TP) and total potassium (TK) returned to the level of uncut plots after a year’s recovery. The LPC, LNC, and N:P were negatively correlated with LA, and LDMC and WD were negatively correlated with SLA, while the effect of SC on fine root traits was limited (p > 0.05). Fine root traits (FRB, RLD, and SRL) were positively associated with SOC, TN, and TP, but negatively correlated with TK. The changes in soil nutrient content caused by the removal of biomass were normal. Increased light and the rapid growth of new trees will increase nutrient regressions; therefore, these results further confirm the feasibility of SC.





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