Growth Analysis of Perennial Plants: The Relative Production Rate and its Yield Components

A new formulation for plant growth analysis, called the relativeproduction rate, is proposed for use in the study of perennialplants. The new measure and its yield components are similarto current growth analysis, but use the annual increment ofgrowth, rather than total accumulated growth, as the basis forassessing performance. The relative production rate removesaccumulated past growth of the perennating structure, a majordeterminant of relative growth rate, and acts independentlyof tree size as a measure of the vigour of growth. The multiplicativeyield components of this relative production rate also providebetter insight into the current morphological and physiologicalfeatures of the tree than the standard growth analysis formulations.Examples are given using Douglas-fir (Pseudotsuga menziesii(Mirb.) Franco) and red pine (Pinus resinosa Ait.) plantationsto illustrate the methodology proposed. Pseudotsuga menziesii (Mirb.) Franco, Pinus resinosa Ait., Douglas-fir, red pine, growth analysis, relative production rate, tree development, competition     

Plant Growth Analysis: Growth and Yield Component Responses to Population Density in Forage Maize

Forage maize (Zea mays L.) was grown in monocultures at populationdensities ranging from 4·9 to 11·1 plants m^–2.Data for plant growth analysis were obtained from six harvestscarried out from 21 to 115 d after planting. Conventional plantgrowth analysis indicated that improvements in forage productivityper unit land area by high population density resulted directlyfrom increased plant presence. Reduction in dry weight per shootat high population density was associated with reduced unitleaf rate. Leaf area ratio was little affected, which may implythat competition for soil nutrients or oxygen was the chiefcause of plant interference. Yield component analysis demonstratedthe increasing importance of population density treatments asa source of variation as growth progressed. Direct relationshipsbetween variation in yield per plant and variation in two yieldcomponents, stem diameter and the inverse of leaf area ratio,were demonstrated. Both conventional plant growth analysis andyield component analysis indicated complex physiological andmorphological adjustments to species population density. Plant growth analysis, yield component analysis, Zea mays L     

Plant Growth Analysis: Allometry, Growth and Interference in Orchardgrass and Timothy

A multiple regression procedure was used to evaluate allometricresponses to stand age and species population densities in monoculturesand mixtures of orchardgrass (Dactylis glomerata L., also knownas cocksfoot) and timothy (Phleum pratense L.). In each speciesthe allometry between shoot dry weight and either leaf areaor tiller number per plant was studied. Population density treatmentsaffected allometry by changing allometric exponents expressingthe ratio of relative growth rates of different plant characteristics.Allometric relationships changed as growth proceeded, and thetwo species differed in their allometric responses to treatments. Plant growth analysis, allometry, competition, Dactylis glomerata L., Phleum pratense L.     

Respiration Modelling and Hypothesis Testing with a Dynamic Model of Sugar Beet Growth

Respiration was predicted quantitatively during sugar-beet growthsimulations by assuming an intimate coupling to growth and maintenanceprocesses. Changes in the growth and maintenance respiratorycoefficients for successive simulations expressed alternativehypotheses regarding the nature of that coupling. Large differencesin yield, partitioning patterns, and the relative importanceof the growth and maintenance components were predicted in responseto changes in respiratory coefficients within the range consideredphysiologically realistic. Beta vulgaris L, sugar beet, respiration, growth yield, mathematical modelling     

Effects of elevated carbon dioxide on three montane grass species: I. Growth and dry matter partitioning

Upland grasslands are a major component of natural vegetationwithin the UK. Such grasslands support slow growing relativelystable plant communities. The response of native montane grassspecies to elevated atmospheric carbon dioxide concentrationshas received little attention to date. Of such studies, mosthave only focused on short-term (days to weeks) responses, oftenunder favourable controlled environment conditions. In thisstudy Agrostis caplllaris L.⁵, Festuca vivipara L. and Poa alpinaL. were grown under semi-natural conditions in outdoor open-topchambers at either ambient (340µmol mol^–1) or elevated(680µmol mol^–1) concentrations of atmospheric carbondioxide (CO₂ for periods from 79 to 189 d, with a nutrient availabilitysimilar to that of montane Agrostis-Fescue grassland in Snowdonia,N. Wales. Whole plant dry weight was increased for A. capillarisand P. alpina, but decreased for F. vivipara, at elevated CO₂.Major components of relative growth rate (RGR) contributingto this change at elevated CO₂ were transient changes in specificleaf area (SLA) and leaf area ratio (LAR). Despite changes ingrowth rate at 680 µmol mol^–1 CO₂, partitioningof dry weight between shoot and root in plants of A. capillarisand P. alpina was unaltered. There was a significant decreasein shoot relative to root growth at elevated CO₂ in F. viviparawhich also showed marked discoloration of the leaves and increasedsenescence of the foliage. Key words: Allometry, growth analysis, elevated CO₂, grasses     

Plant Growth Analysis: A Re-examination of the Methods of Calculation of Relative Growth and Net Assimilation Rates Without Using Fitted Functions

A method is proposed for estimating expected values of meanrelative growth and net assimilation rates, and their variances,over an interval of time, from replicated plant weight and leafarea data at each end of the time interval. The advantage ofthe method is that it avoids the necessity of pairing replicateplants at each of the two harvests, and gives exact resultsfor relative growth rate. The results for net assimilation rateare approximate, but the method proposed still avoids the pairingprocess which is regarded as an artificial necessity inherentin the conventional method. net assimilation rate, relative growth rate, mathematical analysis, Helianthus annuusL, sunflower, Triticum aestiuumL, wheat     

Use of the Expolinear Growth Model to Analyse the Growth of Faba bean, Peas and Lentils at Three Densities: Predictive Use of the Model

The expolinear equation for crop growth (Goudriaan and Monteith,Annalsof Botany66: 695–701, 1990; Goudriaan, 1994. In: MonteithJL, Scott RK, Unsworth MH, eds.Resource capture by crops.Nottingham:Nottingham University Press, 99–110) has the potentialto predict growth under specified environmental conditions.The choice of suitable parameters is discussed and tested usingdata from field experiments with faba bean, peas and lentils(Ishag and Dennett,Annals of Botany82: 497–505. 1998).It is suggested that suitable parameters for predicting cropgrowth are the fraction of solar radiation intercepted at emergence,the extinction coefficient for solar radiation, the maximumfraction of radiation intercepted, the maximum relative growthrate and the maximum crop growth rate for a crop interceptingall the incident radiation. In the experiments considered, thedifferences in growth patterns were due mainly to differencesin the maximum relative growth rate associated with differencesin temperature.Copyright 1998 Annals of Botany Company Expolinear equation, grain legumes, crop growth rate, crop density, relative growth rate, growth modelling, faba bean,Vicia fabaL., peas,Pisum sativumL., lentils,Lens culinarsMedic.     

Integrated Analysis of Growth and Light Interception in Winter Lettuce I. Analytical Methods and Environmental Influences

Measurements on protected lettuce crops have been used to assesstwo new procedures for analysing the rate of dry-matter productionin crops or plant stands. ‘Integrated growth analysis’brings together two traditionally distinct treatments of growthanalysis by resolving crop growth rate (CGR) into stand biomassand the relative growth rate of individual plants. ‘Lightconversion analysis’ resolves CGR as the product of incidentlight receipt, efficiency of light interception by leaves, andefficiency of utilization of intercepted light in dry-matterproduction. Observations from winter lettuce trials were used to fit statisticalprogressions to the primary data and to obtain instantaneously-derivedestimates of all of the analytical components. Trials in threesuccessive years yielded similar patterns in time for the componentsof each of the analytical procedures, giving confidence in theirvalidity. In light conversion analysis, changes in CGR were due mainlyto incident light, which varied threefold, and to interceptingefficiency, which rose from a low initial value to full interceptionat hearting; the efficiency of utilization of light varied lessdramatically, with the value at hearting being about twice thatat planting. In integrated growth analysis a 30 per cent increasein CGR due to CO₂ enrichment, and a 5 per cent increase dueto lower daily minimum temperature, could each be coherentlyresolved into variations in biomass, leaf area ratio and netassimilation rate. In different ways it is concluded that both of these approachescan assist in analysing growth and in identifying the optionsavailable for improving crop yield. Lactuca sativa L., lettuce, growth analysis, crop growth rate, relative growth rate, light interception, light utilization     

Growth Context and Fate of Axillary Meristems of Young Peach Trees. Influence of Parent Shoot Growth Characteristics and of Emergence Date

The relationship between several growth components of a shootand the fates of the axillary meristems (developing in the axilsof the leaves) borne by that shoot were studied, on first-ordershoots of young peach trees. A comprehensive picture of thoserelationships was obtained by a discriminant analysis. Shootgrowth at meristem emergence date was characterized by internodelength, leaf-production rate and leaf-unfolding duration. Allpossible fates of axillary meristems at the end of the growingseason (i.e. blind nodes, single vegetative or flower bud, budassociations, sylleptic or proleptic shoots) were considered.Shoot-elongation rate determined meristem fates quantitatively.The number of buds produced by a meristem increased when theshoot-elongation rate increased. Qualitatively, the fate of axillary meristems was related tothe balance between shoot-growth components. If the subtendingleaf unfolded slowly, sylleptic or proleptic shoots were morelikely to develop than bud associations, for high shoot-elongationrates; and flower buds were more frequent than vegetative buds,for low shoot-elongation rates. Compared to flower buds, blindnodes appeared for similar shoot-elongation rates but longerinternodes and lower leaf-production rates. The emergence dateslightly modified the relation between shoot growth and axillary-meristemfates, but the main features held true throughout the growingseason. The relationships between shoot growth and meristem fates mayresult from competitive interactions between the growing subtendingleaf and the developing axillary meristem. Growing conditionsmight also influence both shoot growth and meristem fates byfavouring either cell enlargement or cell division.Copyright1995, 1999 Academic Press Peach tree, Prunus persica (L.) Batsch, axillary meristem, meristem fate, branching, flowering, shoot growth, discriminant analysis, exploratory analysis     

Growth Analysis of Soybean Seedlings During the Lifespan of the Cotyledons

Patterns of seedling growth of Glycine max in light and darknesswere compared during the period from germination to cotyledonabscission. Fitted growth curves and the derived functions,relative growth rate, unit leaf rate, leaf area ratio and specificleaf area, were used to assess the relative importance in seedlinggrowth of cotyledon storage reserves, cotyledon photosynthesisand leaf photosynthesis. The cotyledons are of an intermediatetype with a predominant storage and a minimal photosyntheticfunction. Cotyledon reserves support seedling growth until theprimary leaves expand, after which growth depends on leaf photosynthesis. Glycine max (L.) Merr., soybean, cotyledons, growth analysis, seedling development     

Use of the Expolinear Growth Model to Analyse the Growth of Faba bean, Peas and Lentils at Three Densities: Fitting the Model

The expolinear equation for crop growth (Goudriaan and MonteithAnnalsof Botany66: 695–701, 1990) was fitted to measurementsof above ground dry weight made on two cultivars of each ofthree species, faba bean (Vicia fabaL.), peas (Pisum sativumL.)and lentils (Lens culinarsMedic.), each grown at three densitiesat the University of Reading, UK in 1992 and 1993. The expolinearequation fitted the data well but required frequent samplingto obtain good estimates of the parameters. The equation hasthree parameters,R_mthe maximum relative growth rate,C_ma maximumcrop growth rate, andt_bthe time at which the crop effectivelyreaches a linear phase of growth.R_mdid not differ between densities,cultivars or species but differed between years.C_mincreasedwith increased density and was lower for lentils than for fababeans or peas.t_bdecreased with increased density for faba beanbut not for the other species. Incorporating an extinction coefficientfor solar radiation and the maximum fraction of radiation interceptedenabled reasonably accurate time courses of leaf area indexto be derived, as suggested by Goudriaan (1994. In: MontiethJL, Scott RK, Unsworth MH, eds.Resource capture by crops. Nottingham:Nottingham University Press, 99–110).Copyright 1998 Annalsof Botany Company Expolinear equation, grain legumes, crop growth rate, crop density, relative growth rate, growth modelling, faba bean,Vicia fabaL., peas,Pisum sativumL., lentils,Lens culinarsMedic.     

Effect of Temperature on Growth of Crotalaria juncea L. and Crotalaria sericea Retz.

Growth performances of Crotalaria juncea L. and C. sericea Retz.have been compared at two controlled temperatures, 16–20°C, and 28–32 °C, with respect to increase ind. wt and leaf area, relative growth rate, leaf area ratio,specific leaf area, leaf weight ratio, net assimilation rate,the ratio of mean relative growth rate to mean relative rateof leaf area increase () and shoot/root ratios. Both the speciesgrew better at the higher temperature; however the relativegrowth rate was more affected by temperature in C. sericea thanin C. juncea. Further, it was observed to be more dependenton net assimilation rate than on the leaf area ratio. Crotalaria juncea L., Crotalaria sericea Retz., relative growth rate, leaf area ratio, specific leaf area, leaf weight ratio, leaf area increase, net assimilation rate, shoot/root ratio     

Growth Analysis of Contrasting Cultivars of Zea mays L. at Different Rates of Nitrogen Supply

The effects of nitrogen supply on the growth and nitrogen contentsof four cultivars of Zea mays L. of different origins were examinedunder water-culture conditions at the seedling stage. Seedlingsof cultivars CNIA12, LG11, Tusa Finn, and UNPHU XC301 were grownunder three different relative addition rates of nitrogen. Growthparameters were determined by means of functional growth analysisconducted on 10 to 19 d-old seedlings. No differences in relativegrowth rates were found among cultivars when nitrogen supplywas high. However, at the lowest rate of nitrogen supply, TusaFina and LG11 showed lower relative growth rates than CNIA12and UNPHU XC301, where relative growth rates were sustainedeven at the lowest rate of nitrogen supply, due to a higherunit leaf rate. The higher unit leaf rate of these two cultivarscorresponds directly to higher leaf and plant nitrogen contents.High positive correlations were found between plant nitrogencontents and both relative growth rate and unit leaf rate. Theresults suggest a potential for selection of genotypes withimproved performance under conditions where high rates of nitrogen-fertilizerapplication are too costly or not desirable.Copyright 1994,1999 Academic Press Maize, Zea mays, growth analysis, maize, nitrogen nutrition, nitrogen content, relative addition rates, relative growth rates, unit leaf rate     

Leaf Growth in Cotton (Gossypium hirsutum L.) 1. Growth in Area of Main-stem and Sympodial Leaves

A model is presented for growth of individual and successivemain-stem leaves of cotton, based on a series of indoor experimentsand data sets from the literature. Three variable parametersare used to describe individual leaf growth: relative growthrate of meristematic tissue (R¹), relative rate of approachof final area (R₂) and a ‘position parameter’ (t_0.5)which governs the transition from meristematic to extensiongrowth. Final area of a leaf does not occur in the model asa deterministic quantity but it is a result of the processesduring growth. The model generates successive mainstem leavesand sympodial leaves as an integrated system. Assimilate shortagesoccurring in the plant operate on R₁ leading to the characteristicchange of final leaf area along the mainstem. Gossypium hirsutumL., cotton, leaf growth, relative growth rate, meristematic tissue, extension growth, mathematical model     

Seedling Growth in Elymus farctus after Episodes of Burial with Sand

Episodes of burial by wind-blown sand are a frequent hazardfor Elymus farctus in the strandline and foredunes. We haveinvestigated the ability of seedlings to withstand and recoverfrom experimental burial. The burial treatments were appliedat the two-leaf stage, either for one or two weeks, and thegrowth in them was compared with that in unburied controls.The method of B-splines, with knots defined at the beginningand end of the burial period, proved to be appropriate for fittingrelationships between In dry mass and time for growth analysis.The relative growth rates derived from these relationships werepartitioned into component relative growth rates for individualplant organs, to reveal the responses to burial in terms ofdry matter allocation. No plants survived two weeks of burial but all those buriedfor one week recovered. There was respiratory loss of dry massduring burial, although fitted relative growth rates were notsignificantly different from zero. On re-exposure, relativegrowth rates increased to equal the maximum values in unburiedplants. Dry mass losses were from the root and stem fractions.Leaf 1 was unaffected, whereas the development of leaf 2 wascurtailed. Apart from their delayed appearance, leaves 3–5behaved similarly to their non-buried counterparts. The maintenanceof leaves at the expense of other organs during burial may becrucial to the survival of E. farctus seedlings. Sand burial, survival, recovery, growth analysis, splined cubic regression, Elymus farctus, sand couch grass     

The Influence of the Rht1 and Rht2 Alleles on the Growth of Wheat Stems and Ears

A field experiment was carried out with a set of near-isogenicspring wheat lines (cv. Triple Dirk) to determine the influenceof the Rht₁ and Rht₂ alleles on the partitioning of dry matterbetween the developing stem and the ear. Each line was sampledtwice weekly and dissected into its component above-ground parts.The rate of change of the dry mass of the individual plant organswas expressed as a proportion of the rate of change of the totalplant dry mass. This ratio was used to assess the relative sinkstrengths of the stem and ear during crop growth. The Rht₁ andRht₂ alleles reduced plant height, but increased grain yield.The greater yield was achieved through a greater grain numberper ear in the Rhtl line, a greater ear number per plant inthe Rht₂ line, and a greater allocation of assimilate to thedeveloping ear than to the developing stem in both Rht lines,particularly at the time of maximum stem growth (17 d beforeanthesis). From the earliest stages of detectable ear growthuntil anthesis, the ear masses per unit area of the Rht₁ andRht₂ lines exceeded that of Triple Dirk (Rht). It was not possibleto determine whether the Rht₁ and Rht₂ alleles were directlyresponsible for increasing grain number per ear and ear numberper plant, respectively, since the increase in these componentsof yield could equally be explained by a greater partitioningof assimilate to developing ears and tillers caused simply bya reduction in plant height. Triticum aestivum L., wheat Rht genes, stem and ear development, dry matter partitioning, allocation ratio     

Differences in the Interacting Effects of Light and Temperature on Growth of Four Species in the Vegetative Phase

A comparative study, employing the concepts of growth analysis,has been made of the varying responses in the early vegetativephase of Gossypium hirsutum, Helianthus annuus, Phaseolus vulgaris,and Zea mays to combinations of light intensity (1.08, 2.16,3.24, 4.32, and 5.4 x 10⁴ lx—photoperiod 14 h) and constantdiurnal air temperatures (10, 15, 20, 25, 30, and 35 °C).Depending on the combination of treatments, the temperatureof the internal tissues departed from air temperature by 6.9to 1.4 °C: so only the internal temperatures are cited here. For each species there are complex interactions between theeffects of light and temperature on the net assimilation rate,the leaf-area ratio, and the relative growth-rates of plantweight and leaf area. The magnitude of the changes induced bythe two factors vary both with the growth component and thespecies. The temperature responses are maximal up to 20–5°C while at the highest temperatures they may be negative.The temperature coefficients for leaf-area ratio are consistentlyless than those of the other three components: here betweenspecies the coefficients over 10–20 °C vary by a factorof 9.6, 5.4, and 5.1 for the rates of gain in plant weight andleaf area and the net assimilation rate, while the orderingwithin each growth component is species dependent. Under conditions of optimal temperature the relative growth-rateand net assimilation rate progressively increase, accordingto the species, up to either 4.32 or 5.4x 10⁴ lx. The leaf-arearatio is always largest at the lowest intensity. The level oflight at which the rate of gain in leaf area reaches a maximumranges from 2.16x 10⁴ lx for Phaseolus to between 4.32 and 5.40x10⁴ lx for Gossypium. The highest relative growth-rate and net assimilation rate ofHelianthus exceed those of Zea substantially. Indeed the maximalassimilation rate for Helianthus of 2.10 g dm^–2 week^–1is the highest ever recorded under field or controlled conditions.Possible reasons for this reversal of the photosynthetic potentialsof the two species observed by previous workers are discussed.     

Leaf Growth in Cotton (Gossypium hirsutum L.) 2. The Influence of Temperature, Light, Water Stress and Root Restriction on the Growth and Initiation of Leaves

The rate parameters R₁, R₂, I/LI and I/t_0.5, which characterizethe growth in area of successive main-stem leaves, probablyall have the same temperature response. Temperature thereforeonly operates on the time scale. Water stress reduces both therelative growth rate and the advance of developmental age, thelatter however to a lesser extent than the former. The effectof root restriction is explained as resulting from mineral shortage. Gossypium hirsutum L., cotton, leaf growth, leaf initiation, relative growth rate, temperature, light, water stress, root restriction     

Regression Smoothers for Estimating Parameters of Growth Analyses

The objective of regression smoothers is to obtain predictedvalues of a dependent variable and its first derivative fromempirical data without having to assume any particular functionalrelationship between the dependent and independent variables.An early variant of this type of analysis, specifically naturalB-splines, was first applied to growth analyses by Parsons andHunt in 1981 (Annals of Botany 48 : 341–352, 1981). Theobject of this paper is to describe and evaluate two recentadvances in this area (cubic spline smoothers and loess smoothers)in the context of plant growth analysis and compare them tonaturalB -splines. The accuracies of these methods are evaluatedusing simulated data of a type that normally causes difficultieswith other methods. A bootstrap procedure is described thatimproves the estimate of the optimal smoother parameter. Itis shown that these smoothers can capture even subtle changesin relative growth rate. The method is then applied to growthdata ofHolcus lanatus. B -splines; cubic spline smoothers; growth analyses; Holcus lanatus ; loess; relative growth rate; RGR