Growth Respiration Research Articles

Quantitative Analysis of Respiration in The Seedling Growth of Summer Forage Crops : II. Maintenance respiration and growth respiration in the seedling growth

Quantitative Analysis of Respiration in The Seedling Growth of Summer Forage Crops : II. Maintenance respiration and growth respiration in the seedling growth

Effects of soil temperature on the carbon exchange of taiga seedlings.: I. Root respiration

Seedlings of Alnuscrispa (Ait.) Pursh, Populusbalsamifera L., Populustremuloides Michx., and Betulapapyrifera Marsh., hardwood species of the taiga of interior Alaska, were grown in sand in a controlled environment room at day–night temperatures of 25 and 20 °C, respectively, with a 20-h day length. After establishment, pots containing each species were placed under soil-temperature treatments of 5, 15, and 25 °C while maintaining extant air-temperature and light regimes. Both total and maintenance respiration of the roots were measured under these temperature treatments by monitoring the efflux of CO2 from the potted soil mass. An estimate of root-growth respiration was calculated as the difference between total and maintenance respiration. Total root respiration increased from three- to five-fold as soil temperature increased over the 20 °C experimental range. Growth-respiration response was species specific, occurring only at 5 °C soil temperature in A. crispa, at both 15 and 25 °C in P. balsamifera, and at all three soil temperatures in P. tremuloides. Growth respiration of the roots was a nearly constant fraction of total root respiration within a species, averaging 0.17 mg CO2•h−1•g root dry weight−1 in A. crispa and P. balsamifera, but nearly twice that, 0.33 mg CO2•h−1•g root dry weight−1, in P. tremuloides. Growth respiration was not determined for B. papyrifera.

Biochemical studies of some cell wall associated enzymes in malathion treated germinating seeds ofVigna sinesis(L): effect of IAA and GA3supplementation

Malathion treatment of the seeds of Vigna sinensis (L), above 50 ppm decreased the seedling growth and respiration rate; it is accompanied by a significant alteration in the activities of different cell wall associated hydrolytic enzymes in the roots of the 72 hour germinated seeds. On the simultaneous application of either of the plant hormones (IAA or GA3) with different concentrations of malathion, it was found that there was a trend to overcome the malathion‐caused inhibition on seedling growth pattern and respiration rate in the roots of the seeds. It was also found that the treatment of the seeds with plant growth hormones, at 100 ppm malathion exposure, helps to restore the normal activities of some cell wall associated hydrolytic enzymes, which showed otherwise significantly altered activities. Above 100 ppm malathion exposure on the seeds, the plant hormones gradually lose their efficiency to counteract the malathion elicited effect on the studied parameters in the roots of the seeds.

Nitrate uptake and respiration in roots and shoots: A model

Respiration in plants is often divided into growth and maintenance components. From the growth respiration it is possible to estimate the efficiency of conversion of substrate to plant material. Analysis of recent experimental data on this basis suggests that the conversion efficiency is considerably lower in roots than in shoots, which conflicts with biochemical analysis. The conventional method for describing respiration data is developed to incorporate root activity and is applied to a set of experimental data. The model provides a means for estimating the respiratory cost of nitrate uptake and also a possible explanation for the inconsistency between experimental observations and theoretical analysis.

Growth and Maintenance Respiration: a Reconciliation of Thornley's Model and the Traditional View*

There are two competing views of the growth and maintenance aspects of plant respiration : a traditional view based on growth analysis which relates respiration to whole plant dry weight and a differential equation formulation which distinguishes between storage material that may be used for growth, non-degradable structure, and degradable structure that degrades at some rate and may be recycled. It is shown how and under what conditions these two mathematical models may be reconciled. Suggestions are made for improving both models.

Modeling Soybean Growth for Crop Management

ABSTRACT Asoybean (Glycine max (L.) Merr.) crop growth simulation model (SOYGRO) was developed to aid farm managers in making irrigation and pest management decisions. Non-linear first order differential equations describe dry matter rates of change, accumulation and depletion of protein pools, and changes in shell and seed numbers. Two data sets from defoliation and irrigation experiments were used for calibration and validation of the model. The model responds well to drought and defoliation stresses for two test cases. Sensitivity analyses of SOYGRO revealed that simulated yield was most sensitive to changes in gross photosynthesis and growth respiration. The sensitivity of simulated yield to changes in model parameters was increased by the occurrence of either water or defoliation stress.

Respiratory Activity in Pea Cotyledons during Seed Development

Three phases were recognized in the course of the respiration rate of pea (Pisum sativum L.) cotyledons during seed development. (1) The respiration rate per cotyledon initially increased along with the mitochondrial activity. (2) During the second phase, the respiration rate increased further until a constant level was reached and then decreased. The mitochondria now started to lose their capacity to oxidize malate, followed by a decreasing capacity to oxidize succinate. (3) During the maturation phase the respiration rate decreased further. The rate of ascorbate oxidation started to decline at this time. Ascorbate oxidation was increasingly stimulated by cytochrome c. The changes in respiration rate are considered in relation to changes in growth and maintenance respiration. When the water content of the seeds was maintained by storing them at high humidity, the respiration rate of cotyledons of early harvested seeds decreased sharply whereas that of later harvested seeds hardly changed. This change in response was used to mark the transition between the second and third phase. During humid storage changes in the functional integrity of the mitochondria still occurred. The results are discussed in relation to the ability of pea seeds to withstand desiccation.

Purine alkaloid formation and CO2 gas exchange in dependence of development and of environmental factors in leaves of Coffea arabica L.

In the leaves of Coffea arabica L., purine alkaloid formation was estimated by analyzing the theobromine and caffeine content and by measuring the methylation rate of [2-(14)C]theobromine to [2-(14)C]caffeine in short-term experiments (6-24 h). At the same time, growth (in terms of dry weight and area), net photosynthesis (NPS), and dark respiration were determined. During leaf development, which was considered to be terminated when NPS was at a maximum (60-80 μmol g(-1) s(-1)) and dark respiration at a minimum (5-7.5 μmol g(-1) s(-1)), the content of theobromine and the velocity of caffeine formation were both found to decrease by a factor of more than 100. The close correlation between the theobromine content and the methylation rate is suspended when purine alkaloid formation is influenced by factors other than leaf development. Among these factors, temperature is the most effective: the velocity of caffeine biosynthesis is increased by raising the temperature and vice versa. Although the plants were well irrigated, a drastic decrease of NPS in the afternoon was observed under all environmental conditions tested. Light saturation was reached between 170-360 μmol m(-2) s(-1). The temperature optimum of NPS was shown to be very broad (24-33°C)m provided the adaptation time was sufficiently long.

Translocation and utilization of carbon in wheat (Triticum aestivum)

Wheat (Triticum aestivum L. cv. SUN 9E) was grown in a growth chamber under conditions of low soil nitrogen. Translocation of carbon to the roots and the subsequent utilization of these carbohydrates was determined. In vegetative plants (22 days old), 21.5 mg C day−1 were translocated to the roots. 29% of this was incorporated into dry matter, 32% was respired (28% via the cytochrome and 4% via a SHAM‐sensitive, presumably the alternative nonphosphorylating, pathway) and 39% was translocated back to the shoots, mainly in the form of amino acids. – The rote of root maintenance respiration during the vegetative phase was estimated to be 0.7 mg O2 h−1 (g dry weight of roots)−1 and the root growth respiration to be 0.41 g O2 (g dry weight of roots)−1. Total carbohydrate utilization due to root respiration via the alternative, nonphosphorylating pathway during the major part of the growth period was calculated to be only ca 6% of carbohydrate utilization for grain growth. The rate of specific mass transfer (SMT) of sugars in the sieve tubes was estimated from the data on C‐translocation and data on the total area occupied by sieve tubes in a cross section of the root system. SMT was calculated to be 0.8 mg sucrose s−1 cm−2, which is very similar to the published value on SMT for other organs, except roots.

Maintenance and growth respiration in shoots and roots of sunflower plants grown at different root temperatures

Continuous measurements of CO2‐evolution and dry matter accumulation were carried out on shoots and roots separately of intact Helianthus annuus L. cv. Autumn Beauty plants grown in nutrient solution at different root temperatures. The data were used to distinguish between growth and maintenance components of respiration. The maintenance and growth coefficients were higher in the root system than in the shoots. The overall efficiency of assimilate utilization was within the range reported in the literature. An increase in root temperature increased the maintenance part of root respiration and, to a lesser degree, also shoot maintenance respiration. Neither root nor shoot growth respiration coefficients were affected by root temperature. It is concluded that the study of whole‐plant respiration masks differences in energy utilization between shoots and roots.

The Influence of Oxygen Deficiency in Roots on CO2 Exchange Rates of Shoots and Distribution of 14C-Photoassimilates of Wheat Seedlings

Summary The effect of anoxia in the root medium of young wheat seedlings on growth, apparent photosynthesis and dark respiration of shoots, and on the growth of roots and the distribution of 14 C among the soluble fraction and starch in shoots, roots and the medium of roots was examined. After 2 – 5 days of anaerobic conditions of roots a gradual and increasing retardation of growth of roots and shoots and also apparent photosynthesis and dark respiration of shoots were observed. Examination of the incorpation of 14 CO 2 and distribution of the label among soluble fraction and starch in shoots, roots and labeled soluble compounds excreted from the roots into their media showed that 24 hours after feeding the plants with 14 C0 2 changes in these characteristicas were only observable in roots and in the media. Under anaerobic conditions there was great leakage of labeled compounds from roots to their medium at the expense of starch. A tentative scheme for the action of anaerobiosis on the processes examined is discussed.

Growth and Maintenance Respiration of Shoot and Roots in Scots Pine Seedlings

Summary Continuous daily measurements of CO 2 -evolution were carried out separately for shoots and roots of intact Scots pine seedlings grown in a water culture under laboratory control!ed conditions, during the first vegetation season. The rates of root respiration at constant temperature during the night were lower than those during the day when plants were photosynthesizing. The obtained results were used for further estimation of growth (constructive)- and maintenance-respiratory coefficients. Both maintenance and growth respiration were greater in the roots than in the shoot.

Growth rate?reserve content relationship as influenced by irradiance, CO2 concentration, and temperature

The patterns of the CO2 exchange of single vegetative bean plants were monitored during steady state exchange and after lowering the irradiance, the CO2 concentration, or the temperature. The measured patterns were used to calculate the dynamics of the rate of synthesis of structural dry matter and of the amount of the reserve materials during the experiments. The rate of synthesis of structural dry matter was assumed to be proportional to growth respiration (total minus maintenance). The growth conversion efficiency was assumed to be independent of the treatments. The maintenance respiration coefficient was taken to be dependent only on the temperature. Change in the amounts of reserve materials was calculated as a difference between the net CO2 input and the amount converted into new structural dry matter.During the first day of a low CO2 uptake a substantial depletion of reserve materials took place also during light hours, since the rate of synthesis of structural dry matter lagged behind the decrease of photosynthesis. On the second day the rate of synthesis was adapted to the low CO2 input and there occurred little change in the amount of reserve materials. There was a rapid increase in the amount of reserve materials after the irradiance was increased again or after temperature was lowered.A saturating dependence of the specific growth rate on the content of reserve materials was found to exist irrespective of the mode of changing the content of reserve materials. A hysteresis-like retardation of the specific growth rate took place after the reserve had already been exhausted for some time. During retardation a replenishment of reserve materials took place.It is suggested that adaptation processes tend to keep the content of reserve materials within a certain (probably optimal) range.

Maintenance Respiration and Carbon Balance of Plants at Low Levels of Sodium Chloride Salinity

The daily course of carbon influx and efflux was measured in young plants of Phaseolus vulgaris, Xanthium strumarium, Zea mays, and Atriplex halimus, exposed to low levels of salinity (NaCl) and varying daytime light intensities. Maintenance respiration (RM) was calculated. In Phaseolus, Xanthium, and Atriplex, RM rose with increasing salinity, approximately up to those levels of salinity above which apparent signs of toxicity appear. At higher levels of salinity RM declined. There was no response of RM to salinity in Zea. At the levels of salinity tested, salinity did not affect the ratio of growth respiration to photosynthesis. At —5 x 105 Pa of NaCl salinity, the increase in RM in Xanthium was calculated to account for 24% of the growth reduction caused by salt. The remainder could be ascribed to reduced photosynthesis. The increase of RM is considered to be indicative of an adaptive mechanism, not present in the very salt-sensitive Zea.

Energy metabolism of Plantago lanceolata as dependent on the supply of mineral nutrients

Plantago lanceolata L., a grassland species from a relatively nutrient‐poor habitat, was grown in nutrient‐rich and in nutrient‐poor culture solutions. Half of the plants were trensferred from high to low or from low to high nutrient conditions. Shoot growth was immediately reduced upon transfer to low nutrient conditions, whilst it reacted more slowly upon transfer of plants to high nutrient conditions. Root growth was less dependent on the supply of nutrients, but it was slightly reduced upon transfer of plants to high nutrient conditions.Photosynthesis was largely independent of the nutrient supply, apart from an initial increase upon transfer of plants to low nutrient conditions. Photosynthesis decreased with age in all treatments, and this decrease was not due to mutual shading. The decrease of photosynthetic rate was not accompanied by a decreased relative growth rate: it was compensated by a more efficient root respiration, since the activity of the alternative nonphosphorylating pathway continuously decreased in plants grown in a high nutrient environment.It is concluded that the alternative pathway was of significance in removal of carbohydrates, which could not be utilized for growth, energy production, etc., due to a temporary or structural imbalance between assimilate production and requirement. The alternative pathway also appeared to allow P. lanceolata plants to adapt to a changed environment as regards mineral nutrition.The experimental value for root growth respiration of P. lanceolata grown under high nutrient conditions was compared with a theoretical value, calculated from the biochemical composition of plant dry matter and the known energy costings for biosynthetic and transport processes. A good correlation between the experimental and theoretical value of root growth respiration was found if it was assumed that ion uptake required c. 1.0 molecule of ATP per ion per membrane passage.

Latitudinal trends in the responses of growth respiration and maintenance respiration to temperature in the beach pea, Lathyrus japonicus

The response of dark respiration to temperature was measured for populations of Lathyrus japonicus collected from 39–56° N latitude. Carbon loss in dark respiration increases with latitude at all temperatures. This increased respiratory activity is attributable to concomitant increases in both the growth and maintenance components of total dark respiration. The possible adaptive significance of these respiratory responses is discussed.

The Effect of Carbohydrate Concentration on the Respiration Rate of Soybean1

Two experiments were conducted to determine the relationship between respiration rate and carbohydrate concentration in source and sink tissue in soybean (Glycine max (L.) Merrill). Experiment I was conducted during V8/R1, R2, and R4 stages of maturity. Defoliation, 92% shading, and control treatments established a range in sugar and starch concentrations for source leaves and the corresponding above.ground sinks at each stage. This range was primarily due to a reduction in source size by defoliation, or a reduction in photosynthate source by shading, thereby reducing the carbohydrate supply to the sinks. This range was primarily due to a reduction in source size by defoliation, or a reduction in photosynthate source by shading, thereby reducing the carbohydrate supply to the sinks. Respiration was positively correlated with carbohydrate content in V8/R1 and R2 tissues in which growth respiration predominates. However, where maintenance respiration likely predominated (R‐4 leaves and pods) the respiration‐carbohydrate content correlations were poor.Experiment II was conducted during the R5 stage of maturity. Control, 92% shading, defoliation, and depodding treatments resulted in a range in sugar and/or starch concentrations in source leaves and pod tissues. Defoliation and shading reduced the carbohydrate supply from the source to the sink as in Experiment I. The two‐thirds depodding treatment was not severe enough to affect the carbohydrate concentration in the pods. However, starch accumulated in the leaves 7 days after the treatment was initiated. A significant positive relationship was found in the R5 leaves among respiration and sugar or starch concentrations. Conversely, an insignificant relationship was found in pods which contained predominately storage tissue undergoing maintenance respiration.

Efficiency of Root Respiration in Relation to Growth Rate, Morphology and Soil Composition

AbstractRoot growth respiration and root maintenance respiration rate of the following species were determined: Hypochaeris radicata L. ssp. radicata L., H. radicata ssp. ericetorum Van Soest, Plantago lanceolata L., P. major L. ssp. major, P. major ssp. pleiosperma Pilgcr, P. maritime L., Senecio viscosus L., S. vulgaris L. and Urtica dioica L. A high root growth respiration (i.e. the amount of oxygen consumed for synthesis of a given weight of root material) implied a high maintenance respiration rate (i.e. the amount of oxygen consumed per unit of time and dry weight, but not connected with growth). High values of both components reflect a low efficiency of root respiratory processes.The efficiency of root respiration, as determined by the values for root growth respiration and root maintenance respiration rate could not be demonstrated to be of advantage in adaptation to soil conditions, as e.g. nitrogen content, moisture content and pH. It is concluded that (he degree of ‘wasteful utilization of sugars’ in roots, i.e. such consumption of sugars as cannot be related to structural growth, storage of carbohydrates or maintenance processes, depends on imbalance of transport of sugars from the shoot to the roots with utilization of sugars for synthesis of root material.The results are discussed in relation to Brouwer's explanation for the equilibrium between the growth of shoots and of roots. Root growth rate in the present species appears limited by a factor produced in the shoot under light conditions, and which factor is distinct from carbohydrates. The evidence presented shows that relatively inefficient root respiration does not imply a low growth rate. In regulation of plant growth the growth rate itself and also the shoot to‐root ratio may be more important than the regulation of the efficiency of energy metabolism.

Influence of Nitrogen Form and Nitrogen Absence on Utilization of Assimilates for Growth and Maintenance in Tops and Roots of Lolium multiflorum

AbstractUtilization of assimilates for growth and maintenance of tops and roots of Lolium multiflorum was determined for plants supplied with either nitrate or ammonium. Carbon dioxide exchange rates were measured continuously for tops and roots separately. Three‐day periods were applied for two irradiation levels. On the last day of each three‐day period no nitrogen was supplied to the two treatments. In the nitrate treatment, the coefficient of utilization for converting assimilates into constructive growth (YG) remained unaffected in absence of nitrate. However, in absence of nitrate the maintenance respiration (M) for both tops and roots was only one third of that in presence of nitrate. In the treatment with ammonium the maintenance respiration of the plants was not influenced by the absence of ammonium. However, especially for the tops YG increased in absence of ammonium. In both the treatments, growth respiration of the roots was inefficient compared to that of the tops. Only in the case of absence of nitrate, maintenance respiration of the roots was similar to that of the tops.

Respiration and Concentration of Water Soluble Carbohydrate in Plant Parts of Contrasting Tall Fescue Genotypes1

Little information is available concerning genotypic differences in dark respiration (RD) of plant tissues. The objectives of these studies were to determine if a gradient of RD (02 uptake) existed along the leaf blade and to compare maintenance respiration, growth respiration, and concentration of water‐soluble carbohydrate (WSC) leaf blades, terminal meristems areas, and root tips of seven genotypes of tall rescue (Festuca arundinacea Schreb.). Three genotypes had been selected for contrasting yield/tiller, and four genotypes had been selected for contrasting CO2 exchange rate (CER)‐yield relationships.Center portions of mature leaf blades had the highest rate of RD and were used in subsequent leaf studies. Dark respiration of mature leaf blades probably reflected maintenance respiration since it was independent of measured carbohydrate levels and leaf growth had ceased. Rates of RD 3 hours after the photoperiod began were similar to those measured after 48 hours of darkness in elongating leaves and terminal meristems. Concentrations of WSC in these tissues were decreased during the dark period, but probably not enough to stop respiration associated with the growth component. Respiration of root tips was not significantly different among genotypes selected for contrasting yield/tiller, but was decreased to about 44% of the original rate by the 48‐hour dark treatment. That rate may have represented the maintenance component. Rates of RD of mature blades and terminal meristems of low, medium, and high yield/tiller genotypes corresponded to their yield/tiller classification. Conversely, among the four genotypes selected for their differential CER‐yield relationship, the low CER‐Iow yield genotype had the highest RD of mature leaf blades and terminal meristems.In general, concentrations of WSC within tissues did not differ significantly among genotypes. Terminal meristems had a significantly higher concentration of WSC than did other plant tissues studied, and weights of WSC per terminal meristem were significantly different among genotypes. These data showed that genetic variation for RD existed in tall rescue, that RD was different for tissues within a plant, and that 48 hours in darkness was insufficient to decrease WSC enough to clearly separate the growth and maintenance components of RD in tall fescue.