Similar Growth Stages Research Articles

Importance of the Phyllochron in Studying Development and Growth in Grasses

The phyllochron, which is defined as the interval between similar growth stages of successive leaves on the same calm, has been used extensively to describe and understand development of grasses. The purpose of this paper is to introduce seven papers presented as part of the symposium Understanding Development and Growth in Grasses: Role of the Phyllochron Concept. Environmental (temperature, water, and day length) factors and genetics affect the duration of the phyllochron. The following seven papers broaden the discussion of these topics and present new concepts about how the environment and genetics impact the relationship between leaf appearance and whole plant development.

Expression of the 3-phosphoglycerate kinase gene (pgkA) of Penicillium chrysogenum.

The sequence of the Penicillium chrysogenum pgkA gene promoter was determined up to 952 nucleotides (nt) 5' to the major transcriptional start point (position +1), and contains a 38 bp pyrimidine-rich region within which transcription initiates at this and two minor sites (-11, -23). A 21 bp segment (-99 to -79) closely matches a region which is essential for the expression of the Aspergillus nidulans pgkA gene. A further region was found with similarity to sequences in other A. nidulans promoters possibly effecting response to carbon source. The terminator region of the P. chrysogenum pgkA gene was sequenced as far as 192 nt 3' to the stop codon and three polyadenylation sites were found at 94, 103 and 107 nt from this point, the first preceded by a possible polyadenylation signal. No transcription termination signal was found but several regions potentially forming stem-loop-structures were noted. A single 1.3 kb pgkA mRNA was readily detected by Northern blot analysis of total cellular RNA. Steady-state levels of pgkA mRNA were 1.5 to 2.0 times greater in mycelium harvested at similar stages of growth from medium containing the carbon sources acetate or quinate compared to glucose. A transformed strain of P. chrysogenum containing a fusion of the pgkA promoter to the Escherichia coli lacZ reporter gene integrated at the oliC locus was constructed, and beta-galactosidase activity monitored during growth of batch cultures in defined media. The pgkA promoter activity increased during exponential growth and was 2-3 times greater and increased most rapidly in mycelium grown on quinate or acetate compared to glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

The extraction and quantification of ergosterol from ectomycorrhizal fungi and roots

Recently, ergosterol analysis has been used to quantify viable fungal biomass in resynthesized ectomycorrhizae. An objective of our study was to quantify ergosterol in a range of ectomycorrhizal isolates under differing growth conditions. In addition, we tested the applicability of the method on field-collected roots of ectomycorrhizal and vesicular-arbuscular (VA) mycorrhizal plants. Quantification of sitosterol as a biomass indicator of plant roots was also undertaken. Ergosterol was not detected in roots of uninoculated Betula populifolia seedlings, and sitosterol was not detected in an ectomycorrhizal fungal isolate but was present in birch roots. Ergosterol was produced in all isolates examined, which represented the major orders of ectomycorrhizal fungi. The range of values obtained, from 3 to nearly 18 μg ergosterol mg-1 dry mass, agrees well with reported values for other mycorrhizal and decomposer fungi. Hyphal ergosterol was the same during growth on phytic acid and KH2PO4. Reduction of growth temperature from 25° C to 15° C had little effect on ergosterol content of cultures harvested at similar growth stages. Ergosterol and sitosterol were detected in field-collected ectomycorrhizae of B. populifolia and Pinus sylvestris and VA mycorrhizae of Acer rubrum and Plantago major. Both ergosterol content and ergosterol to sitosterol ratios were significantly lower in VA mycorrhizae than ectomycorrhizae. Calculations of viable fungal biomass associated with field-collected roots were in agreement with those reported by others using the method on resynthesized ectomycorrhizae. Estimates of total mass could be obtained for field-collected B. populifolia roots by a simultaneously using ergosterol to estimate fungal biomass and sitosterol to estimate root mass. Some potential applications and limitations of sterol quantification in studies of mycorrhizal physiology and ecology are discussed.

A uniform decimal code for growth stages of crops and weeds

SummaryA universal scale (to be known as the BBCH scale) using a decimal code for the description of the growth stages of most agricultural crops and weeds is proposed. The scale and codes are based on the well‐known Zadoks code for cereals.Developmentally similar growth stages of different crops are given the same codes. The general scale provides a framework within which more specific scales for individual crops may be constructed. The uniformity of the scale makes it easy to remember and use in agricultural practice and simplifies storage and retrieval in a computer system.A description of the general scale is given followed by specific scales for cereals, rice, maize, oilseed rape, field beans, peas and sunflower. Comparisons with scales currently in use are given where appropriate.

Influence of pH and plant nutrient status on ion fluxes between tomato plants and simulated acid mists.

Diffusion along concentration gradients, ion exchange, active uptake, and physical damage are possible mechanisms causing fluxes of ions between plant tissues and acidified moisture on plant surfaces. The temporal patterns of ion fluxes during individual wetting events should vary in a predictable manner in relation to moisture pH, plant nutritional status, and the operational mechanism. Tomatoes (Lycopersicon esculentum Mill.) were grown hydroponically at relative nutrient addition rates (Ra ) of 7, 12, and 15% per day. At similar growth stages, the plants were exposed to HCl-acidified mists of pH 2-5, 4-0, or 5-6 for 4 h, or left unmisted as controls. Whole-plant throughfall was analysed for pH and ion concentrations after 15, 30, 60, 120, and 240 min. Surface chemical contamination was minimized by pre-rinsing with deionized water. Except for H+ during the first 15-30 min, all ions showed efflux for the duration of the mistings. Effluxes were low (< 150μequiv m-2 h-1 ), time-invariant, and unrelated to Ra at mist pH of 4.0 and 5.6. At pH 2.5, effluxes of K+ , Mg2+ , NO3 - , and PO4 3- increased over time, while Ca2+ efflux increased during the first hour, then remained constant. Maximum efflux (105 to 730 μequiv m-2 h-1 ) mostly occurred at pH 2.5 and Ra = 17 % d-1 , increasing in the order NH4 + = SO4 2- < NO3 - < PO4 3- < Ca2+ = Mg2+ < K+ < H+ . These results suggested that although ion diffusion and ion exchange contributed to observed effluxes, an additional mechanism, temporally accumulating physical damage to cuticles and cell membranes below a threshold pH between 4˙0 and 2˙5, was involved. Foliar concentrations of K, Ca, and Mg did not differ significantly among treatments, but ion effluxes into pH 2-5 mists removed 1-13 % of the whole-plant element contents, with the largest removal for Ca.

A comparison of the personality type dimensions of the 1987 Inc. 500 company founders/CEOs with those of slower-growth firms

A popular misconception holds that most new businesses experience similar growth stages of start-up, rapid growth, maturity, and decline. Yet, business statistics show that only a small number of firms grow into large organizations. A few experience some growth, but the majority have such small growth that they provide only a marginal income to the founder. While market conditions impact on the growth of the firm, they do not explain growth differences when they occur under similar market conditions. In this paper, the authors have compared psychological type preferences of founders/CEOs of fast-growth firms with those of slow-growth firms under the assumption that differences in psychological preferences, as they relate to gathering, assimilating, and processing information, would have an impact on the strategic or growth orientation of the firm. The results are based on the administration of the Myers-Briggs Type Indicator to the founders/cofounders of 143 firms included in the 1987 Inc. 500 list of the fastest-growing private companies in the United States and the comparison of these results with those of an earlier study of 150 founders/CEOs of successful, yet slower growing firms. The primary personality traits under consideration were an individual's preferred method of gathering information from the environment, making decisions, and drawing conclusions from the information. The results indicate that founders of rapid-growth firms have psychological preferences that are significantly different from those of their slower-growth counterparts. Growth oriented founders prefer an intuitive approach or consideration of future possibilities when gathering information, and a thinking or planned and organized approach to drawing conclusions. These preferences represent those facets most frequently used in strategic or growth planning. Investors in new firms that place importance on the capabilities and orientations of the management team as an evaluation criteria are currently limited to consideration of past experiences. An awareness of the management team's experiences can provide an indication of management ability, but unless their experience involves management of growth, the information related to growth propensities or orientations is limited. A measure of a person's preferences in gathering, assimilating, and processing information can indicate their desires for strategic and/or growth planning. Hence, investors may have another tool that can be used in the investment decision making process. In addition, government policy makers may have the opportunity for increased effectiveness in assistance programs by recognizing that the needs and preferences of founders of rapid-growth companies are significantly different from those of their slower-growing counterparts, and that these differences should be considered in the development of assistance programs.

COMPARISON OF MAIZE (Zea mays L.) GROWTH AND NITROGEN PARAMETERS UNDER HYDROPONIC AND FIELD CONDITIONS

A comparison of biomass and nitrogen (N) parameters from 23 maize (Zea mays L.) inbreds was conducted between hydroponic culturing during two growth chamber studies and soil in the field for two harvests during 1984. The growth chamber studies and first field harvests were sampled at a similar growth stage (approximately nine-leaf); the second field harvest was at anthesis. Shoot dry matter accumulation was greater under hydroponic than under field conditions at a similar vegetative growth stage. Significant inbred differences for shoot biomass, reduced and total N contents and reduced and total N concentrations were determined for the growth chamber and both field harvests. Correlation coefficients were low and not significant (P &lt; 0.05) between inbred parameters in the growth chamber and in the field. In summary, traits from hydroponic plants were not predictive of those from field plants. However, N parameters and biomass of inbreds harvested in the field at a mid-vegetative stage were predictive of inbred performance at anthesis.Key words: Zea mays L., maize, biomass, nitrogen, field, hydroponic

Response of Soybean to Foliage Loss in Taiwan

Insect damage to soybean, Glycine max (L.) Merrill, was simulated by defoliating plants to study the effect on yield in Taiwan. Plants in the field were hand defoliated at 10, 25, and 50% rates at intervals from V2 to R7 growth stages; all experiments were done during 1981 and 1982 spring seasons. Single defoliations at the 10 and 25% levels did not significantly affect yield, but 50% defoliation at R3, R4, or R5 stage reduced seed yield significantly. Two consecutive defoliations at all three rates and performed at R3 + R4, at 25 and 50 %rates at R2 + R3, and at 50% rate at R4 + R5 and R5 + R6 significantly reduced soybean yields. A50%defoliation at any three consecutive stages reduced yield significantly. Three consecutive defoliations at 10 or 25% reduced yield significantly only when performed between R2 and R5 stages. Midreproductive stages were the most sensitive to defoliation, and early vegetative and late reproductive were the least. Yield reduction was caused mainly by reduction in seed size. The level of yield reduction was greater in Taiwan than observed in North America for similar rate and plant growth stage defoliation. Defoliation by removal of the entire leaflet resulted in highest yield loss, whereas defoliation by cutting leaflets a long the midrib resulted in least yield loss.

Basis for Differential Susceptibility of Rice (Oryza sativa), Wild Rice (Zizania palustris), and Giant Burreed (Sparganium eurycarpum) to Bentazon

The basis for differential susceptibility of tolerant rice (Oryza sativaL.), susceptible wild rice (Zizania palustrisL.), and susceptible giant burreed (Sparganium eurycarpumEngelm. # SPGEU) to foliar application of 1.1 kg ai/ha of bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was investigated by evaluating herbicide absorption, translocation, and metabolism. Giant burreed and wild rice absorbed more bentazon than rice at similar growth stages. Less than 10% of the absorbed bentazon was translocated out of the treated leaf of any of the species. Differential tolerance of bentazon among the three species was due to differences in the rate of bentazon metabolism. Rice metabolized 98% of the bentazon retained in the treated leaf 1 day after treatment (DAT), while giant burreed and wild rice metabolized less than 2% of the bentazon retained in the treated leaf 5 DAT.

Comparison of the winter development, reproduction and lifespan of viviparae of Sitobion avenae (F.) and Rhopalosiphum padi (L.) (Hemiptera: Aphididae) on wheat and perennial rye grass in England

AbstractThe mid-winter development, reproduction and survival of field-acclimatized viviparae of Sitobion avenae (F.) and Rhopalosiphum padi (L.) on leaves of tillering wheat and perennial ryegrass (Lolium perenne) plants at similar growth stages were compared by monitoring batches of aphids in clip-cages in field plots in southern England. For both aphid species, survival, total fecundity and reproductive rate were much higher on wheat than on L. perenne, and on both host-plants they were much higher for S. avenae than for R. padi. Development times (in day-degrees) were longer on L. perenne than on wheat, and on both host-plants were longer for R. padi than for S. avenae, though these differences were less marked. Comparison of the results with those of earlier studies suggests that large changes in cereal aphid performance occur between summer and winter and that these are both aphid-specific and host-plant-specific.

Levains lactiques: corrélation entre les dénombrements sur gélose et l'ATP cellulaire

Cellular ATP concentrations from six commercial cheddar cheese starter cultures propagated in skim milk under varying growth conditions were estimated. High correlations (r ≥ 0.98) were obtained between cellular concentrations from a specific culture and its corresponding plate counts at various phases of growth. However, major discrepancies were noticed in ATP concentrations from one starter culture to another at similar growth stages: no significant correlation could be found between ATP concentrations and corresponding plate counts when data from all six starter cultures were pooled. No significant correlation could be obtained for the same starter culture propagated under varying growth conditions.[Translated by the journal]

Light and electron microscopy of embryo development in perennial and annual Medicago species

The embryo of perennial Medicago sativa L. and annual M. scutellata (L.) Mill. have similar growth stages, but the perennial embryo is smaller and its rate of growth is slower than that of the annual by about 3 days. Transfer cells in the suspensor and embryo sac of late heart stages suggest different major pathways of nutrient flow in the two species. Transfusion tissue at the base of the embryo sac in the ovule of M. scutellata may facilitate solute transport and promote rapid embryo growth. Plastids in the suspensor cells of heart and late heart stages of the two species contain a dense matrix, membrane-bounded plastid vacuoles, starch, and a dense core. The plastid core in M. sativa has stacked tiers of straight tubules about 24 nm in diameter, suggesting that these specialized plastids are like tubular chromoplasts. Plastid vacuoles arise from the periphery of dense cores and apparently discharge electron-translucent contents into the suspensor cytoplasm. Plastid vacuoles may play a role in suspensor metabolism and thus influence embryo development.

Photosynthesis and Degree of Polymerization of Fructan during Reproductive Growth of Meadow Fescue at two Temperatures and two Photon Flux Densities

Accumulation of dry weight was measured in plant parts of meadow fescue (Festuca pratensis Huds.) that was grown at 16/11 °C or 26/21 °C and with 20 or 60 nE cm-2 s_1 photosynthetically active radiation. Plants reached anthesis about 3 weeks later at 16/11 °C than at 26/21 °C and had then a higher proportion of dry weight in inflorescences and less in leaf blades. Growth temperature had little effect on C02 exchange rate (CER) but plants grown at 60 nE cm-2 s_1 had higher CER than those grown at 20 nE cm-2 s-1. The concentration of water-soluble carbohydrates (WSC) at similar growth stages was usually higher at 16/11 °C than at 26/21 °C. High radiation also led to higher WSC in stem and leaf tissue. Root tissue changed least and WSC did not exceed 10% of dry weight during the experiment. In all tissues, when WSC was high, the fructans were distributed into a group with a high degree of polymerization (DP) and another with a low DP. The low DP group included sucrose, reducing sugars and fructans up to about 20 units long. An apparent threshold concentration of WSC was necessary for synthesis of the high DP fructans. This concentration was near 12% for leaf tissue, about 6% for stem base tissue, and 2-5% for root tissue. The average apparent DP of the high DP fructan group was 43 to 50 for leaf tissue, 31 to 93 for stem base tissue, and 27 to 31 for roots. These characteristics appeared to be mostly tissue dependent with less effect from temperature and radiation.

EFFECT OF WATERING REGIME ON YIELD, WATER USE AND LEAF CONDUCTANCE OF SEVEN FESTUCA SPECIES WITH CONTRASTING LEAF RIDGING

SummarySeedlings of seven Festuca species with contrasting leaf surface morphology were grown in pots with three different watering regimes to simulate full irrigation, intermittent soil moisture stress or prolonged soil moisture stress.When harvested at a similar growth stage, plants subjected to the greatest stress had the least shoot dry matter. Differences between treatments were greatest in the fastest growing plants, e.g. F. arundinacea cv. S.170. At harvest, mean transpiration rate was lowest in plants from the least stressed treatment and in species with the flattest leaf surfaces e.g. F. drymeja and F. gigantea. Whether or not allowance was made for the effect of the convolutions of the leaf surfaces in increasing effective leaf surface area, the ranking of the species for transpiration rate per unit leaf area under well watered conditions was the same.Overall water use efficiency (WUE) was greatest in plants subjected to prolonged soil moisture stress (383 mg shoot dry matter per 100 g of water transpired) and least in those which were intermittently stressed (301 mg per 100 g). WUE was also greater for the flatter leaved species, the greatest being for F. gigantea (437 mg per 100 g) and least for F. scariosa (275 mg per 100 g). These variations in water use efficiency were not closely related to daily maximum stomatal conductance or to stomatal density of the leaves.WUE was not highly correlated with any of the other parameters measured. At best, 46 % of the variation was associated (negatively) with the final rate of transpiration which in turn was closely correlated (positively) with the degree of adaxial leaf surface ridging.

The tolerance of black currant flowers to induced frosts

SUMMARYFlower buds on potted plants of 17 varieties of black currant were frosted to ‐3.3, ‐4.5 and ‐5.2 °C between the grape stage and full flower in 1979 and 1980. In all varieties more flower buds died after the ‐5.2 °C frosts and at full flower, and less after the ‐3.3 °C frosts and at the grape stage. Varieties related to Ben More and Ojebyn tolerated the ‐4.5 °C frosts until after first flower while Baldwin and Magnus became susceptible at the grape stage. Seabrooks Black, Greens Black and Ben Lomond and its relatives were intermediate. In both years flower buds tolerated frosts to similar growth stages but in 1980 the varieties flowered about 2 wk earlier than in 1979 and suffered more frost damage at full flower. The frosted plants had slightly larger fruits than the unfrosted ones in 1979. The immature fruit drop was similar in frosted and unfrosted plants in both years except when it was increased after ‐5.2 °C in 1980. It is pointed out that for reliable cropping, varieties should flower late as well as tolerate spring frosts and that tests of frost tolerance should be done for at least three growth stages.

Characterization of soluble nucleohistone and histone from cotyledons of germinating seeds of Pinus pinea

Soluble nucleohistone and histones have been isolated from cotyledons of Pinus pinea; this is the first such isolation from any gymnosperm tissue. The nucleohistone isolated was similar in composition and physical characteristics to that of chromatin reported for comparable angiosperm tissues at similar stages of growth. Histones, purified by gel electrophoresis, possessed eight subfractions which are tentatively identified as follows in order of increasing electrophoretic mobility: very lysine-rich F1 (fractions 1–4), arginine-rich F3 (fraction 5), arginine-rich F2a2 (fraction 6) and F2b (fraction 7), as well as moderately arginine-rich F2a1 (fraction 8). Nucleohistone from days 15 to 22 of germination, a period of cell elongation in cotyledons, possessed greater amounts of histone, acidic protein, and RNA relative to DNA than day-14 'mitotically active' nucleohistone. Histone acetylation from sodium acetate, methylation from s-adenosyl-L-methionine, and phosphorylation from inorganic phosphate proceeded at low rates in isolated nuclei. Phosphorylation from [32P]ATP occurred to a greater extent; very lysine-rich F1 and arginine-rich F3 histones were phosphorylated to the greatest degree while F2a1 was phosphorylated least.

Resistance to Cereal Leaf Beetle in Wheat: Density and Length of Leaf‐surface Pubescence in Four Wheat Lines1

Measurements of leaf hair length and quantity of leaf hairs were made from seedlings of four wheat (Triticum aestivum L. em. Thell.) cultivars to develop bench marks for certain genotypes and to determine the effect of leaf size on hair density. Length was measured from photographs of cleared leaf material; density was determined directly from cleared material with the aid of a compound microscope. The superior resistance of Cl 9321 to oviposition of Oulema melanopus (L.), compared with that of ‘Selkirk,’ occurred because of the greater hair density of Cl 9321. The hair length of Selkirk was probably the main factor responsible for the greater resistance of this cultivar compared with that of ‘Chris.’ The importance of choosing leaves of similar growth stages for pubescence studies was demonstrated.

The pepsin soluble dry matter of leaf and stem fractions of grasses in relation to voluntary intake by sheep

The level of pepsin soluble dry matter (PSDM) was determined on leaf and stem fractions derived from five grasses each cut at three stages of growth. The voluntary intake and dry matter digestibility of all grass fractions had been previously determined with sheep. Mean PSDM for leaf and stem were similar (23.0 v. 23.4 per cent) despite large differences in voluntary intake (57.8 v. 39.6 g/kg W0.75 )and similar dry matter digestibility (52.6 v. 55.8 per cent). For all grass fractions the correlation between voluntary intake and PSDM was r = 0.26, P &gt; 0.05. This poor relation was partly caused by a significant difference between the leaf and stem populations. It was concluded that PSDM was an unreliable guide for predicting the voluntary intake of grasses when compared at similar stages of growth.

Assessment of veld condition and trend

Abstract Advice on veld management generally assumes that the productivity of veld can be improved by management. There is thus a need in agricultural extension work, where botanical surveys are impractical, for a basis on which changes in veld condition can be judged and recorded. It is suggested that a score sheet for the assessment of condition be based on five criteria, namely, cover density, botanical composition, vigour, soil surface condition and insect damage. Using score sheets and photographs, trend in veld condition may be established by comparing successive condition assessments recorded at representative sites at similar growth stages or seasons. Knowledge of potential climax condition is presupposed in the use of present‐condition” score sheets.

Growth of Birdsfoot and Alfalfa. III Changes in Carbohydrates Reserves and Growth Analysis Under Field Conditions1

The amount of total available carbohydrates (TAC) in the roots of 'Empire' birdsfoot trefoil were lower and the changes were less pronounced than in the roots of 'Vernal' alfalfa at similar growth stages. The difference on a weight basis was much greater than by percentage. Starch, sucrose, glucose, and fructose were the components of the TAC of both species. Relationships among the fractions of the TAC were similar for both species throughout the growing season.Alfalfa had a higher crop growth rate (CGR) than trefoil except at late stages of maturity when growth of trefoil continued by active upper axillary branching. CGR of alfalfa was higher than trefoil because there was a greater leaf area and it developed faster. Alfalfa was more efficient in the conversion of radiant energy into dry matter because it had a higher leaf area index than trefoil at comparable net assimilation rates. This advantage over trefoil was attributed to a higher photosynthetic rate for alfalfa leaves and to a better light distribution in the taller alfalfa canopy.