scholarly journals Light Effects on Wax Begonia: Photosynthesis, Growth Respiration, Maintenance Respiration, and Carbon Use Efficiency

2004 ◽  
Vol 129 (3) ◽  
pp. 416-424 ◽  
Author(s):  
Krishna S. Nemali ◽  
M.W. van Iersel
Keyword(s):  
Growth Period ◽  
Dry Weight ◽  
Carbon Gain ◽  
Maintenance Respiration ◽  
Gross Photosynthesis ◽  
Carbon Use Efficiency ◽  
Whole Plant ◽  
Growth Respiration ◽  
Use Efficiency ◽  
Gas Exchange System

The effect of increasing daily light integral (DLI; 5.3, 9.5, 14.4, and 19.4 mol·m-2·d-1) on photosynthesis and respiration of wax begonia (Begonia semperflorens-cultorum Hort.) was examined by measuring CO2 exchange rates (CER) for a period of 25 d in a whole-plant gas exchange system. Although plant growth rate (GR, increase in dry weight per day) increased linearly with increasing DLI, plants grown at low DLI (5.3 or 9.5 mol·m-2·d-1) respired more carbohydrates than were fixed in photosynthesis during the early growth period (13 and 4 d, respectively), resulting in a negative daily carbon gain (DCG) and GR. Carbon use efficiency [CUE, the ratio of carbon incorporated into the plant to C fixed in gross photosynthesis (Pg)] of plants grown at low DLI was low, since these plants used most of the C fixed in Pg for maintenance respiration (Rm), leaving few, if any, C for growth and growth respiration (Rg). Maintenance respiration accounted for a smaller fraction of the total respiration with increasing DLI. In addition, the importance of Rm in the carbon balance of the plants decreased over time, resulting in an increase in CUE. At harvest, crop dry weight (DWCROP) increased linearly with increasing DLI, due to the increased photosynthesis and CUE at high PPF.

scholarly journals Growth Respiration, Maintenance Respiration, and Carbon Fixation of Vinca: A Time Series Analysis

2000 ◽  
Vol 125 (6) ◽  
pp. 702-706 ◽  
Author(s):  
Marc W. van Iersel ◽  
Lynne Seymour
Keyword(s):  
Carbon Balance ◽  
Carbon Fixation ◽  
Plant Size ◽  
Carbon Gain ◽  
Maintenance Respiration ◽  
Carbon Use Efficiency ◽  
Size Growth ◽  
Growth Respiration ◽  
Use Efficiency ◽  
Traditional Approaches

Respiration is important in the overall carbon balance of plants, and can be separated into growth (Rg) and maintenance respiration (Rm). Estimation of Rg and Rm throughout plant development is difficult with traditional approaches. Here, we describe a new method to determine ontogenic changes in Rg and Rm. The CO2 exchange rate of groups of 28 `Cooler Peppermint' vinca plants [Catharanthus roseus (L.) G. Don.] was measured at 20 min intervals for 2 weeks. These data were used to calculate daily carbon gain (DCG, a measure of growth rate) and cumulative carbon gain (CCG, a measure of plant size). Growth and maintenance respiration were estimated based on the assumption that they are functions of DCG and CCG, respectively. Results suggested a linear relationship between DCG and Rg. Initially, Rm was three times larger than Rg, but they were similar at the end of the experiment. The decrease in the fraction of total available carbohydrates that was used for Rm resulted in an increase in carbon use efficiency from 0.51 to 0.67 mol·mol-1 during the 2-week period. The glucose requirement of the plants was determined from Rg, DCG, and the carbon fraction of the plant material and estimated to be 1.39 g·g-1, while the maintenance coefficient was estimated to be 0.031 g·g-1·d-1 at the end of the experiment. These results are similar to values reported previously for other species. This suggests that the use of semicontinuous CO2 exchange measurements for estimating Rg and Rm yields reasonable results.

scholarly journals Acclimation of Plant Populations to Shade: Photosynthesis, Respiration, and Carbon Use Efficiency

2005 ◽  
Vol 130 (6) ◽  
pp. 918-927 ◽  
Author(s):  
Jonathan M. Frantz ◽  
Bruce Bugbee
Keyword(s):  
Growth Models ◽  
Photon Flux ◽  
Carbon Gain ◽  
Low Light ◽  
Carbon Use Efficiency ◽  
Grand Rapids ◽  
Use Efficiency ◽  
Gas Exchange System ◽  
Photosynthesis And Respiration

Cloudy days cause an abrupt reduction in daily photosynthetic photon flux (PPF), but we have a poor understanding of how plants acclimate to this change. We used a unique 10-chamber, steady-state, gas-exchange system to continuously measure daily photosynthesis and night respiration of populations of a starch accumulator [tomato (Lycopersicon esculentum Mill. cv. Micro-Tina)] and a sucrose accumulator [lettuce (Lactuca sativa L. cv. Grand Rapids)] over 42 days. All measurements were done at elevated CO2 (1200 μmol·mol-1) to avoid any CO2 limitations and included both shoots and roots. We integrated photosynthesis and respiration measurements separately to determine daily net carbon gain and carbon use efficiency (CUE) as the ratio of daily net C gain to total day-time C fixed over the 42-day period. After 16 to 20 days of growth in constant PPF, plants in some chambers were subjected to an abrupt PPF reduction to simulate shade or a series of cloudy days. The immediate effect and the long term acclimation rate were assessed from canopy quantum yield and carbon use efficiency. The effect of shade on carbon use efficiency and acclimation was much slower than predicted by widely used growth models. It took 12 days for tomato populations to recover their original CUE and lettuce CUE never completely acclimated. Tomatoes, the starch accumulator, acclimated to low light more rapidly than lettuce, the sucrose accumulator. Plant growth models should be modified to include the photosynthesis/respiration imbalance and resulting inefficiency of carbon gain associated with changing PPF conditions on cloudy days.

scholarly journals A Multiple Chamber, Semicontinuous, Crop Carbon Dioxide Exchange System: Design, Calibration, and Data Interpretation

2000 ◽  
Vol 125 (1) ◽  
pp. 86-92 ◽  
Author(s):  
M.W. van Iersel ◽  
B. Bugbee
Keyword(s):  
Environmental Control ◽  
Dark Respiration ◽  
Net Photosynthesis ◽  
Data Interpretation ◽  
Crop Growth ◽  
Carbon Gain ◽  
Carbon Dioxide Exchange ◽  
Gross Photosynthesis ◽  
Carbon Use Efficiency ◽  
Use Efficiency

Long-term, whole-crop CO2 exchange measurements can be used to study factors affecting crop growth. These factors include daily carbon gain, cumulative carbon gain, and carbon use efficiency, which cannot be determined from short-term measurements. We describe a system that measures semicontinuously crop CO2 exchange in 10 chambers over a period of weeks or months. Exchange of CO2 in every chamber can be measured at 5 min intervals. The system was designed to be placed inside a growth chamber, with additional environmental control provided by the individual gas exchange chambers. The system was calibrated by generating CO2 from NaHCO3 inside the chambers, which indicated that accuracy of the measurements was good (102% and 98% recovery for two separate photosynthesis systems). Since the systems measure net photosynthesis (Pnet, positive) and dark respiration (Rdark, negative), the data can be used to estimate gross photosynthesis, daily carbon gain, cumulative carbon gain, and carbon use efficiency. Continuous whole-crop measurements are a valuable tool that complements leaf photosynthesis measurements. Multiple chambers allow for replication and comparison among several environmental or cultural treatments that may affect crop growth. Example data from a 2 week study with petunia (Petunia ×hybrida Hort. Vilm.-Andr.) are presented to illustrate some of the capabilities of this system.

scholarly journals Irrigation Regimens Differentially Affect Growth and Water Use Efficiency of Two Southwest Landscape Plants

2000 ◽  
Vol 18 (2) ◽  
pp. 66-70 ◽  
Author(s):  
Linda B. Stabler ◽  
Chris A. Martin
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Dry Weight ◽  
Shoot Length ◽  
Feedback Effects ◽  
Landscape Plants ◽  
Whole Plant ◽  
Cercidium Floridum ◽  
Use Efficiency ◽  
Ambient Co2

Abstract Growth and water use efficiency (WUE) of two, common Southwest landscape plants, red bird of paradise (Caesalpinia pulcherrima L.) and blue palo verde (Cercidium floridum Benth. Ex A. Gray), were studied in response to three irrigation regimens (frequent, moderate, and infrequent) that mimicked a range of residential landscape watering practices in Phoenix, AZ. During 50 to 58 and 138 to 147 days after the start of irrigation treatments (DAT), mid-day measurements of shoot water potential (Ψ), osmotic potential (Ψ0), and gas exchange were made. Concurrently, diurnal measurements of whole plant transpiration (T) and estimates of dry weight accrual were made to calculate WUE. More frequent irrigations increased shoot length of both species and dry weight of Cercidium. For both species, Ψ and Ψ0 showed patterns of osmotic regulation as the substrate dried between watering events for moderately and infrequently irrigated plants. Infrequently irrigated Caesalpinia and Cercidium had the lowest WUE, except for 138 to 147 DAT during which time infrequently irrigated Cercidium had the highest WUE. Instantaneous transpiration efficiency (ITE) was negatively correlated to the ratio of intracellular to ambient CO2 (Ci/Ca) in all treatments, suggesting that under more frequently irrigated conditions, WUE of Caesalpinia and Cercidium might be reduced by negative feedback effects of high Ci/Ca ratios on stomatal conductance.

scholarly journals Acclimation of Wax Begonia to Light Intensity: Changes in Photosynthesis, Respiration, and Chlorophyll Concentration

2004 ◽  
Vol 129 (5) ◽  
pp. 745-751 ◽  
Author(s):  
Krishna S. Nemali ◽  
Marc W. van Iersel
Keyword(s):  
Leaf Area ◽  
Dark Respiration ◽  
Chlorophyll Concentration ◽  
Physiological Parameters ◽  
Carbon Gain ◽  
Leaf Chlorophyll ◽  
Whole Plant ◽  
Area Basis ◽  
Gas Exchange System ◽  
Leaf Chlorophyll Concentration

Physiological acclimation of plants to light has been studied mostly at the leaf level; however whole-plant responses are more relevant in relation to crop growth. To examine the physiological changes associated with different daily light integrals (DLI) during growth of wax begonia (Begonia semperflorens-cultorum Hort.), we grew plants under DLI of 5.3, 9.5, 14.4, and 19.4 mol·m-2·d-1 in a whole-plant gas exchange system. Photosynthesis-light response curves of groups of 12 plants were determined after 25 d of growth. Physiological parameters were estimated per m2 ground area and per m2 leaf area. On a ground area basis, significant increases in dark respiration (Rd), quantum yield (α), the light compensation point (LCP), and maximum gross photosynthesis (Pg,max) were seen with increasing DLI. Variations in physiological parameters among different treatments were small when corrected for differences in leaf area. On a leaf area basis, α, LCP, and the light saturation point (LSP) did not change significantly, whereas significant increases in Rd and Pg,max were seen with increasing DLI. There was a small decrease in leaf chlorophyll concentration (6.3%, measured in SPAD units) with increasing DLI. This study indicates that wax begonias acclimate to low DLI by increasing their leaf chlorophyll concentration, presumably to more efficiently capture the available light, and to high DLI by increasing Pg,max to efficiently utilize the available light, thereby maximizing carbon gain under both situations.

Whole-plant respiration and its temperature sensitivity during progressive carbon starvation

2015 ◽  
Vol 42 (6) ◽  
pp. 579 ◽  
Author(s):  
Martijn Slot ◽  
Kaoru Kitajima
Keyword(s):  
Temperature Sensitivity ◽  
Critical Role ◽  
Temperature Sensitive ◽  
Maintenance Respiration ◽  
C Balance ◽  
Whole Plant ◽  
Growth Respiration ◽  
Proportional Increase ◽  
Plant Level ◽  
Plant Respiration

Plant respiration plays a critical role in the C balance of plants. Respiration is highly temperature sensitive and small temperature-induced increases in whole-plant respiration could change the C balance of plants that operate close to their light-compensation points from positive to negative. Nonstructural carbohydrates are thought to play an important role in controlling respiration and its temperature sensitivity, but this role has not been studied at the whole-plant level. We measured respiration of whole Ardisia crenata Sims. seedlings and tested the hypothesis that darkness-induced C starvation would decrease the temperature sensitivity of whole-plant respiration. Compared with control plants, sugar and starch concentrations in darkened plants declined over time in all organs. Similarly, whole-plant respiration decreased. However, the temperature sensitivity of whole-plant respiration, expressed as the proportional increase in respiration per 10°C warming (Q10), increased with progressive C starvation. We hypothesise that growth respiration was suppressed in darkened plants and that whole-plant respiration represented maintenance respiration almost exclusively, which is more temperature sensitive. Alternatively, changes in the respiratory substrate during C starvation or increased involvement of alternative oxidase pathway respiration may explain the increase in Q10. Carbohydrates are important for respiration but it appears that even in C-starved A. crenata plants, carbohydrate availability does not limit respiration during short-term warming.

Shoot and Root Interference of Common Cocklebur (Xanthium strumarium) and Soybean (Glycine max)

Weed Science ◽  
1993 ◽  
Vol 41 (1) ◽  
pp. 34-37 ◽  
Author(s):  
Robert C. Bozsa ◽  
Lawrence R. Oliver
Keyword(s):  
Field Experiments ◽  
Plant Root ◽  
Soybean Seed ◽  
Growth Period ◽  
Dry Weight ◽  
Porous Membrane ◽  
Xanthium Strumarium ◽  
Shoot Dry Weight ◽  
Whole Plant ◽  
Plant Interference

Field experiments were conducted in 1986 and 1987 to determine the effects of shoot and root interference of common cocklebur and soybean. Plants were grown in porous membrane envelopes. Common cocklebur plants had a longer vegetative growth period than soybean and were twice as tall as soybean at maturity. Soybean root and shoot dry weight and seed yield were reduced by shoot and whole plant (root and shoot) interference of common cocklebur, with whole plant interference giving the greatest reduction. Common cocklebur growth was affected little by soybean interference. Common cocklebur shoot interference alone reduced total soybean seed weight by 48%, the amount caused by common cocklebur whole plant interference.

scholarly journals Study on screening of canola varieties with high light use efficiency and evaluation of selecting indices

OCL ◽  
2020 ◽  
Vol 27 ◽  
pp. 43
Author(s):  
Rui Wang ◽  
Wenli Peng ◽  
Liyong Hu ◽  
Weixian Wu
Keyword(s):  
Cluster Analysis ◽  
Seed Weight ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Principal Component ◽  
Growth Period ◽  
Dry Weight ◽  
High Light ◽  
Light Use Efficiency ◽  
Use Efficiency

High light use efficiency is an important factor for yield improvement during the growing season for winter canola. This study explored the evaluation method of high light use efficiency during the whole growth period in order to screen high light use coefficient of crop genotypes in canola producing areas of Southwest China. The pot experiment was conducted with sixty canola cultivars which had already been planted in the crops planting areas of the middle and upper reaches of Yangtze River. The plant height, root neck diameter, number of pods per main inflorescence, pods per plant, dry weight of shoots, seed weight per plant, pericarp weight per plant, ratio of pericarps to seeds weight per plant, seeds number per pod and 1000-grain weight were investigated under the shading treatment of reducing the incoming solar light by 20%. The high light use coefficient of canola cultivars was evaluated comprehensively by principal component analysis, membership function, cluster analysis and stepwise regression analysis. With these analyses, the original twelve indices related to light use efficiency could be synthesized into the four independent indices which represented 86.4% of all the investigated information of canola with high photosynthetic efficiency. Sixty varieties were classified into three groups by cluster analysis, and ZS12, GYZ6, FY792, RHY6, CZY3 and ZYZ19 displayed higher light use efficiency; such 18 varieties as XDZY9, XY1, YY50 and so on, were medium light efficient ones; and the rest 36 varieties such as LY9, ZYZ781, SG127 and so on, fell to the relatively lower light use efficiency categories. The comprehensive evaluation in this study had screened such four indicators as the stem dry weight per plant, the pod number per plant, the seed number per pod and the 1000-seed weight, which could be regarded as identification indicators for high light use efficiency of canola.

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