Growth and ecophysiological responses of black spruce seedlings to elevated CO2 under varied water and nutrient additions

1993 ◽  
Vol 23 (6) ◽  
pp. 1033-1042 ◽  
Author(s):  
Kurt H. Johnsen
Keyword(s):  
Gas Exchange ◽  
Black Spruce ◽  
Seedling Emergence ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Pressure Potential ◽  
Foliar N ◽  
Nutrient Additions ◽  
Xylem Pressure Potential ◽  
Ecophysiological Responses

Two controlled-environment studies examined growth and ecophysiological responses of black spruce (Piceamariana (Mill.) B.S.P.) seedlings to elevated CO2 under varied water and nutrient additions. Growth analyses were conducted followed by measurements of gas exchange, xylem pressure potential and foliar N concentrations. Growth under elevated CO2 (700 ppm) increased final seedling dry weights by 20–48% compared with seedling growth under ambient CO2 (350 ppm). Percent increases in seedling dry weight were greater under drought versus well-watered conditions and higher versus lower nutrient additions. Seedlings grown under elevated CO2 displayed higher water use efficiency than seedlings grown under ambient CO2. This was apparent based upon instantaneous gas exchange as well as xylem potential pressure measurements. Elevated CO2-induced stimulation of relative growth rate was greatest shortly after seedling emergence and decreased with increased seedling size. Acclimation of net photosynthesis was observed and was reversible. Analyses using allometric principles indicate net photosynthetic acclimation resulted from: (i) growth-induced nutrient dilution; (ii) a decrease in foliar N levels not owing to dilution; and (iii) a decrease in net photosynthetic activity.

Critical Period of Weed Interference in Transplanted Tomatoes (Lycopersicon esculentum): Growth Analysis

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 476-481 ◽  
Author(s):  
Susan E. Weaver ◽  
Chin S. Tan
Keyword(s):  
Lycopersicon Esculentum ◽  
Critical Period ◽  
Growth Analysis ◽  
Canopy Temperature ◽  
Dry Weight ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Fruit Number ◽  
Weed Interference ◽  
Xylem Pressure Potential

The critical period of weed interference in transplanted tomatoes (Lycopersicon esculentumMill. 'Springset’) was from 28 to 35 days after transplanting. A single weeding during this period was sufficient to prevent yield reductions. A growth analysis revealed that significant differences in plant dry weight and fruit number between tomatoes from weed-free and weed-infested plots were not apparent until 56 to 70 days after transplanting. The shorter the initial weed-free period, or the longer weeds were allowed to remain in the plots before removal, the earlier reductions in tomato dry weight and fruit number appeared. Weed interference was due primarily to shading rather than water stress. Tomatoes from weed-infested plots had significantly lower stomatal conductances than those from weed-free plots, but did not differ in xylem-pressure potential or in canopy temperature. If tomatoes were kept weed-free for more than 28 days, or when weeds were present for less than 28 days after transplanting, stomatal conductances were not significantly reduced.

Internal and external control of net photosynthesis and stomatal conductance of mature eastern white pine (Pinusstrobus)

1992 ◽  
Vol 22 (9) ◽  
pp. 1387-1394 ◽  
Author(s):  
C.A. Maier ◽  
R.O. Teskey
Keyword(s):  
Internal Control ◽  
Leaf Gas Exchange ◽  
Net Photosynthesis ◽  
Leaf Conductance ◽  
External Control ◽  
White Pine ◽  
Eastern White Pine ◽  
Pressure Potential ◽  
Growing Seasons ◽  
Xylem Pressure Potential

Leaf gas exchange and water relations were monitored in the upper canopy of two 25 m tall eastern white pine (Pinusstrobus L.) trees over two consecutive growing seasons (1986 and 1987). Examination of the seasonal and diurnal patterns of net photosynthesis and leaf conductance showed that both internal and external (environmental) factors were controlling net photosynthesis and leaf conductance. Internal control was indicated by a rapid increase and then decrease in the photosynthetic capacity of 1-year-old foliage during the development and maturation of current-year foliage, which was independent of environmental conditions. Large differences in net photosynthesis were observed between growing seasons due to seasonal differences in soil water availability, as indexed by predawn xylem pressure potential. Water stress reduced the maximum rate of net photosynthesis and altered the response of net photosynthesis and leaf conductance to absolute humidity deficit.

scholarly journals Flooding Reduces Gas Exchange and Growth in Snap Bean

HortScience ◽  
1991 ◽  
Vol 26 (4) ◽  
pp. 372-373 ◽  
Author(s):  
Bharat P. Singh ◽  
Kevin A. Tucker ◽  
James D. Sutton ◽  
Harbans L. Bhardwaj
Keyword(s):  
Gas Exchange ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Quadratic Model ◽  
Snap Bean ◽  
Blue Lake ◽  
Relationship Of ◽  
The Relationship ◽  
Best Fit ◽  
Prior Stress

This study was conducted to determine the effect of various flooding durations on the growth, water relations, and photosynthesis of the snap bean (Phaseolus vulgaris L.). Greenhouse-grown plants of cv. Blue Lake 274 were flooded for 0 (control), 1, 3, 5, or 7 days. Leaf water potential (ψ), stomatal conductance (gs), transpiration (E), and net photosynthesis (Pn) were measured at the completion of the flooding period and after recovery for 7 days. Root, stem, and leaf dry weights were recorded after plants were allowed to recover from the flooding stress for 7 days. The values for ψ, gs, E, and Pn decreased quadratically with the increase in the duration of flooding. The Pn of plants flooded for 1 day was 17% lower than that of the control and it reached near zero in plants flooded for 7 days. The decrease in Pn after 1 day of flooding was not associated with ψ or gs; however, for longer duration of flooding, Pn decline coincided with the decline in gs. A week after the cessation of flooding, the level of recovery in ψ, E, and Pn was linear and that in gs quadratic to the duration of prior stress experienced by the plant. However, after recovering for 7 days, none of the flooded plants regained gas exchange activities at par with the control. The relationship of stem dry weight to duration of flooding was linear, while a quadratic model provided the best fit for the regression of root and leaf dry weight on the number of days of flooding. Overall, even 1 day of flooding reduces photosynthesis in snap bean and causes a decrease in dry weight of the plant. the extent of decrease in both increasing with the duration of flooding.

scholarly journals Effect of fertigation with potassium and nitrogen on gas exchange and biomass accumulation in eggplant1

2017 ◽  
Vol 47 (3) ◽  
pp. 345-352
Author(s):  
Álvaro Henrique Cândido de Souza ◽  
Roberto Rezende ◽  
Marcelo Zolin Lorenzoni ◽  
Fernando André Silva Santos ◽  
André Maller
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use ◽  
Biomass Accumulation ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Internal Co2 ◽  
Use Efficiency ◽  
Total Dry Weight

ABSTRACT Adequate crop fertilization is one of the challenges for agriculture. Measuring gas exchange and biomass accumulation may be used to adjust crop management. The effect of fertigation with potassium (0 kg ha-1, 54 kg ha-1, 108 kg ha-1 and 216 kg ha-1) and nitrogen (0 kg ha-1, 67 kg ha-1, 134 kg ha-1 and 268 kg ha-1) on gas exchange and biomass accumulation in eggplant was assessed under greenhouse conditions. The net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, instantaneous carboxylation efficiency, water-use efficiency and total dry weight were evaluated. With the exception of K for water-use efficiency and N for internal CO2 concentration, all the other gas exchange parameters were significantly affected by the K and N doses. There was an interaction between N and K doses for net photosynthesis, stomatal conductance, transpiration and instantaneous carboxylation efficiency. The highest values for net photosynthesis, stomatal conductance, transpiration rate, carboxylation instantaneous efficiency and total dry weight were found in the range of 125-185 kg ha-1 of K and 215-268 kg ha-1 of N.

Photorespiration and internal recycling of CO2 in the submersed angiosperm Scirpus subterminalis

1980 ◽  
Vol 58 (6) ◽  
pp. 591-598 ◽  
Author(s):  
Morten Søndergaard ◽  
Robert G. Wetzel
Keyword(s):  
Gas Exchange ◽  
Time Course ◽  
Free Water ◽  
Net Photosynthesis ◽  
Open Water ◽  
Dry Weight ◽  
Experimental Conditions ◽  
Gas Exchange Characteristics ◽  
Gas Space ◽  
A Minor

The presence and magnitude of photorespiration in the submersed freshwater angiosperm Scirpus subterminalis Torr. was investigated by gas-exchange characteristics in an open water-flow system. The minimal rates of photorespiration during active photosynthesis were measured by following the time course of differential 14CO2 and 12CO2 uptake. At 8 mg O2 L−1 (equal to oxygen saturation at 20 °C), the rate was 0.4 μg C (mg organic dry weight)−1 h−1, which was about 10% of net photosynthesis under the experimental conditions. Increasing the oxygen concentration to 30 mg O2 L−1, enhanced photorespiration to 30% of net photosynthesis. It was shown that the concentration of oxygen affected net photosynthesis, CO2 evolution into CO2-free water in the light, the post-illumination CO2 burst, and the CO2 compensation point.The effect of the internal gas space on recycling of CO2 was investigated by comparing gas-exchange by intact and sectioned leaves. About 30% of the CO2 of photorespiratory origin was recycled internally within the lacunal system. The gas-exchange characteristics of Scirpus were similar to those observed in terrestrial C3 species although of a minor magnitude and a different time course. The ecological implications of these finds are discussed.

Effects of variable nitrogen fertilization on growth, gas exchange, and biomass partitioning in black spruce and tamarack seedlings

2005 ◽  
Vol 83 (12) ◽  
pp. 1574-1580 ◽  
Author(s):  
M. Anisul Islam ◽  
S. Ellen Macdonald
Keyword(s):  
Gas Exchange ◽  
Growth Response ◽  
Black Spruce ◽  
Dry Weight ◽  
N Fertilization ◽  
Biomass Partitioning ◽  
Fertilizer Treatment ◽  
Total Biomass ◽  
Growing Seasons ◽  
Net Assimilation

To compare the ability of black spruce ( Picea mariana (Mill.) BSP) and tamarack ( Larix laricina (Du Roi) K. Koch) to adjust to variable edaphic conditions, as found in natural peatlands, we varied N fertilization of seedlings in a growth chamber experiment over two growing seasons and examined growth, biomass partitioning, and gas exchange. Seedlings from both species received either high N (100 µg·L–1) or low N (10 µg·L–1) in consecutive growing seasons as follows: (i) low N and low N (LL), (ii) low N and high-N (LH), (iii) high N and low N (HL), and (iv) high N and high N (HH). Both species had greater shoot and total dry weight after 1 year in the high-N treatment as compared with seedlings grown for 1 year under low-N. For tamarack, these differences were larger and they also exhibited a positive effect of fertilization on net assimilation and water use efficiency. Only black spruce exhibited a positive growth response following the move to higher N fertilization in the second year (LL versus LH), whereas only tamarack exhibited a negative growth response following the move to lower N fertilization (HH versus HL). Still, tamarack had greater total biomass at the end of 2 years than did black spruce, irrespective of fertilizer treatment. Both species had greater total biomass in the HL treatment than in the LH treatment. Tamarack seems able to take advantage of favorable nutrient conditions, but it also experiences more dramatic growth declines under poor or deteriorating conditions. While black spruce grows more slowly than tamarack, it is somewhat buffered from declines in growth under poor or deteriorating conditions. Each species appears to be adapted in its own way to the edaphic heterogeneity that exists in natural boreal peatlands.

Seed pre-treatment using a derivative of 5-hydroxybenzimidazole (AMBIOL) pre-acclimates carrot seedlings to drought

2002 ◽  
Vol 82 (1) ◽  
pp. 195-202 ◽  
Author(s):  
Lada R. Rajasekaran ◽  
Terence J. Blake
Keyword(s):  
Root Growth ◽  
Dry Matter ◽  
Net Photosynthesis ◽  
Membrane Capacitance ◽  
Dry Matter Production ◽  
Pressure Potential ◽  
Drought Acclimation ◽  
Matter Production ◽  
Xylem Pressure Potential ◽  
Pre Treatment

The possibility that AMBIOL, a derivative of 5-hydroxybenzimidazole, may promote drought acclimation of carrot seedlings was studied. Carrot seeds were pre-treated by soaking in AMBIOL solutions of 0, 0.1, 1 or 10 mg L–1 for 24 h and germinated. Fifteen-day-old seedlings were exposed to a 7-d drought by withholding water until soil moisture content declined to one-third of the initial values. Drought caused a significant reduction in xylem pressure potential, elongation growth, leaf area expansion, root growth and dry matter production. Membrane capacitance, net photosynthesis, stomatal conductance, transpiration and water use efficiency all declined in all plants under drought. However, seed pre-treatment using AMBIOL 0.1 and 10 mg L–1 completely alleviated the drought-induced reduction in shoot dry matter production. Seed preconditioning using AMBIOL 10 mg L–1 promoted dry matter production, which was 214% higher than in the untreated droughted plants and was even 26% higher than that of the untreated, unstressed controls. AMBIOL appeared to have induced drought acclimation through root adjustments that enhanced root growth, possibly supplying root-derived essential factors. Key words: Acclimation, antioxidant, carrot, drought, dry matter production, 5-hydroxybenzimidazole, growth, membrane capacitance

Influence of flooding and soil temperature on the water relations and morphological development of cold-stored black spruce and white spruce seedlings

1987 ◽  
Vol 17 (8) ◽  
pp. 821-828 ◽  
Author(s):  
Steven C. Grossnickle
Keyword(s):  
Root Growth ◽  
Soil Temperature ◽  
Cold Storage ◽  
Black Spruce ◽  
White Spruce ◽  
Morphological Development ◽  
Pressure Potential ◽  
Xylem Pressure Potential ◽  
Soil Temperatures ◽  
Flow Through

Fall-lifted, cold-stored black spruce (Piceamariana (Mill.) B.S. P.) and white spruce (Piceaglauca (Moench) Voss) seedlings [Formula: see text] were planted in a controlled environmental chamber with an air temperature of 20 °C, soil temperatures of 10 or 20 °C, and flooded or nonflooded soil treatments. Stomatal conductance (gwv) was lower in flooded seedlings compared with nonflooded seedlings for both black spruce and white spruce seedlings. Black spruce seedlings drained after 14 days of flooding showed gwv similar to nonflooded seedlings, while drained white spruce seedlings had gwv patterns greater than nonflooded seedlings. White spruce seedlings had diurnal xylem pressure potential (ψx) patterns slightly more negative in the flooded treatment compared with the nonflooded treatment. Measured predawn ψx was found to be more negative in flooded seedlings compared with nonflooded seedlings in both black spruce and white spruce. In both species, flooded seedlings 1 day out of cold storage had a greater resistance to water flow through the soil–plant–atmosphere continuum (RSPAC) compared with non-flooded seedlings. After 21 days out of cold storage, rspac decreased in nonflooded seedlings of both species, while flooded seedlings of both species had high RSPAC values. For both black spruce and white spruce seedlings, flooded soils inhibited root growth, while low soil temperatures resulted in a reduction in root growth in nonflooded seedlings. Shoot growth of white spruce seedlings was not influenced by 21 days of flooding or low soil temperature, while the combination of 21 days of flooding and low soil temperature in black spruce seedlings resulted in less shoot development compared with nonflooded seedlings.

CO2 stimulation and response mechanisms vary with light supply in boreal conifers

2020 ◽  
Author(s):  
Qing-Lai Dang ◽  
Jacob Marfo ◽  
Fengguo Du ◽  
Rongzhou Man ◽  
Sahari Inoue
Keyword(s):  
Elevated Co2 ◽  
Picea Glauca ◽  
Boreal Forests ◽  
Black Spruce ◽  
Net Photosynthesis ◽  
Growing Season ◽  
White Spruce ◽  
Light Supply ◽  
Ecophysiological Responses ◽  
Light Effects

Abstract Aims Black spruce (Picea mariana [Mill.] B.S.P.) and white spruce (Picea glauca [Moench] Voss.) are congeneric species. Both are moderately shade tolerant and widely distributed across North American boreal forests. Methods To understand light effects on their ecophysiological responses to elevated [CO2], 1-year old seedlings were exposed to 360 and 720 µmol mol -1 [CO2] at three light conditions (100, 50 and 30% of full light in the greenhouse). Foliar gas exchanges were measured in the mid- and late-growing season. Important Findings Elevated [CO2] increased net photosynthesis (Pn) and photosynthetic water use efficiency, but it reduced stomatal conductance and transpiration. The stimulation of photosynthesis by CO2 was greatest at 50% light and smallest at 100%. Photosynthesis, maximum carboxylation rate (Vcmax) and light saturated rate of electron transport (Jmax) all decreased with decreasing light. Elevated [CO2] significantly reduced Vcmax across all light treatments and both species in mid-growing season. However, the effect of elevated [CO2] became insignificant at 30% light later in the growing season, with the response being greater in black spruce than in white spruce. Elevated [CO2] also reduced Jmax in white spruce in both measurements while the effect became insignificant at 30% light later in the growing season. However, the effect on black spruce varied with time. Elevated [CO2] reduced Jmax in black spruce in mid-growing season in all light treatments and the effect became insignificant at 30% light later in the growing season, while it increased Jmax later in the season at 100% and 50% light. These results suggest that both species benefited from elevated CO2, and that the responses varied with light supply, such that the response was primarily physiological at 100% and 50% light, while it was primarily morphological at 30% light.

Effect of Biostimulants on Drought Tolerance of Ornamental Annuals

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 539d-539
Author(s):  
S.A. Geer ◽  
T.J. Smalley ◽  
M.W. Rieger
Keyword(s):  
Drought Tolerance ◽  
Relative Water Content ◽  
Dry Weight ◽  
New Haven ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Shoot Dry Weight ◽  
Salvia Splendens ◽  
Xylem Pressure Potential ◽  
Relative Water

This study determined the effect of the granular humate Earthgreen (Menefee Mining Corp., Dallas) and the biostimulant ROOTS2™ (LISA Products Corp., New Haven, Conn.) on drought tolerance of the ornamental annuals Impatiens wallerana `Accent White' and Salvia splendens `Red Hot Sally'. Earthgreen was incorporated into the soil and ROOTS2™ applied as a root drench at transplanting and 30 days after transplanting, Transplants were established in greenhouse beds under irrigated conditions for 8 weeks, then subjected to a five week drought. Data indicates rates of 43.9 and 87.9 g·m–2 of Earthgreen or 300 ml of 1% or 2% ROOTS2™ per plant had no significant effect on Salvia shoot dry weight or chlorophyll content of Salvia or Impatiens at the end of the 8-week establishment period. However, Salvia flower dry weight was significantly increased with the higher rate of Earthgreen. During the 5-week drought, Earthgreen or ROOTS2™ did not significantly affect xylem pressure potential of Salvia or relative water content of Impatiens. After the 5-week drought no significant effect of either product on shoot dry weight of Salvia or Impatiens or flower dry weight of Salvia was observed.

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