Relative Growth Response Research Articles

Physiological responses of the eulittoral macroalgaStictosiphonia hookeri(Rhodomelaceae, Rhodophyta) from Argentina and Chile: salinity, light and temperature acclimation

The marine red alga Stictosiphonia hookeri was isolated from three locations in cold-temperate Chile and Argentina, and the comparative ecophysiology of the isolates was studied. The growth response in relation to various salinity, light and temperature conditions was investigated and photosynthesis-irradiance curves were determined. The effect of increasing salinity on the intracellular concentration of the sugar alcohol sorbitol, and the accumulation/degradation kinetics of this compound, were studied. All isolates are characterized as euryhaline, eurythermal and low-light-adapted organisms because of the growth and photosynthesis response patterns. With increasing salinities the macroalgae accumulated high concentrations of sorbitol, which acts as an organic osmolyte and compatible solute. However, this process requires more than 24 h, and hence is too slow to contribute to osmotic acclimation within a tidal cycle. The geographic distribution and the growth versus temperature data indicate infraspecifi...

PHYSIOLOGICAL ECOTYPES IN THE MARINE ALGA BOSTRYCHIA RADICANS (CERAMIALES, RHODOPHYTA) FROM THE EAST COAST OF THE U.S.A1

ABSTRACTThe comparative ecophysiology of nine culture isolates of the eulittoral red alga Bostrychia radicans (Montagne) Montague collected at sites from seven states along the east coast of the U.S.A. was investigated. The growth response in relation to different salinity and light conditions as well as photosynthesis‐irradiance curves were studied. In addition, the effect of salt treatment on the content of the isomeric polyols d‐sorbitol and d‐dulcitol was also studied. All isolates grew between salinities of 5.3 and 70 ppt but with quite different optima and maxima. The isolates were all adapted to low light levels, i.e. growth was already recorded at 2.5 μmol photons·m−2·s−1, and growth rates peaked between 40 and 60 μmol photons·m−2·s‐1. These low‐light requirements were also reflected by the photosynthesis‐irradiance curves: all plants had low light compensation points (2.5–9.7 μmol photons ·m−2·−1) and low photon fluence rates for initial saturation of photosynthesis (38.1–84.7 μmol photons·m−2·s−1, indicating that these isolates are “shade‐adapted.” Isolates from Florida and Georgia synthesized and accumulated both the osmolytes d‐sorbitol and d‐dulcitol in increasing salinities, whereas only d‐sorbitol was present in plants from North Carolina north to Connecticut. d‐sorbitol was always strongly involved in osmotic acclimation. In various isolates from the same location in South Carolina, both polyol patterns were found, i.e. d‐sorbitol plus d‐dulcitol and d‐sorbitol only. All data indicate that B. radicans exhibits a broad salinity tolerance and a low‐light preference, which explain the successful colonization of this alga on various intertidal and shaded substrates. The data also clearly indicate intraspecific differences among the nine isolates, which is interpreted as development of different physiological ecotypes.

Grazing Evaluation of Bigalta and Floralta Limpograss

The use of limpograss [Hemarthria altissima (Poir) Stapf et C.E. Hubb.] as a pasture plant is a relatively recent development. Available cultivars possess distinctly different characteristics. ‘Bigalta’ limpograss has been widely planted on peninsular Florida Spodosols, but stand loss under grazing is common. A more persistent cultivar, ‘Floralta’, has recently become the most widely grown limpograss cultivar in Florida. When grown in the same pasture, Bigalta was heavily grazed by yearling steers (Bos indicus L. and Bos taurus L. spp.) before any noticeable grazing of Floralta occurred. A series of grazing trials was conducted to investigate relative forage quality and plant growth responses of the two cultivars under grazing. Eight 0.5‐ha pastures were established to provide duplicate treatments of two stocking rates on each cultivar. Three summer grazing trials and two autumn grazing trials were conducted. Patterns of grazing differed distinctly between the two cultivars with distinct patchy grazing on Bigalta and rather uniform grazing of the upper canopy of Floralta. Bigalta had higher in vitro organic matter digestibility (IVOMD) and crude protein (CP) than Floralta in most instances, with Bigalta at the light stocking rate averaging 520 g kg−1 IVOMD and 61 g kg−1 CP vs. 480 g kg−1 IVOMD and 51 g kg−1 CP for Floralta. Bigalta produced greater average daily gains (ADG) than did Floralta prior to deterioration of Bigalta stands with 0.5 kg ADG on Bigalta vs. 0.3 kg on Floralta in 1986 and 1987 trials. Bigalta stands deteriorated rapidly especially when subjected to the higher stocking rate, but extended deferment from grazing allowed some stand recovery.

Photosynthetic and Growth Responses of Variegated Ornamental Species to Elevated CO2

Variegated and completely green cultivars of oleander (Nerium oleander L.) and willow myrtle (Agonis flexuosa (Willd.) Sweet) were grown in controlled environment cabinets for 3 and 5 months, respectively, under either ambient levels of CO2 or with supplementary CO2 to a partial pressure of 800 μbar. Photosynthesis of entirely green leaves and the green portions of variegated leaves on both species was greatly stimulated by high CO2 and there was no evidence of downward adjustment (acclimation) of photosynthetic rates to high CO2 during the experiment. Dark respiration rates of these leaves were lowered by high CO2. The yellow portions of willow myrtle leaves showed a low level of photosynthetic activity which was stimulated by high CO2; however, dark respiration rates showed little response to elevated CO2. Green and yellow areas on variegated leaves of willow myrtle had much lower dark respiration rates than completely green leaves, but this difference was not evident for oleander. Yellow portions of oleander leaves showed little evidence of photosynthetic capacity. This was also confirmed by a low photochemical efficiency as determined by chlorophyll fluorescence. A major effect of variegation was to slow overall plant growth compared with completely green plants. The respective 3-fold and 6-7-fold differences in biomass between fully green and variegated cultivars of oleander and willow myrtle was closely related to estimated net carbon gain per day by the plant canopy. Variegation for both species averaged close to 50:50, green:yellow areas. Variegated plants developed about twice the leaf area ratio and specific leaf area compared with their completely green counterparts. The relative growth response to high CO2 was significantly greater for the variegated plants compared to the completely green plants.

Assessing the Effects of the Naked Neck Gene on Chronic Heat Stress Resistance in Two Genetic Populations

The effect of the naked neck (Na) gene on resistance to chronic heat stress was studied in the F2 generation of two populations of chickens genetically differing in growth. The Na gene was introduced into the Athens-Canadian randombred (ACRB), a small BW population, and into a large BW commercial broiler population. Naked neck and normally feathered birds were maintained in either a chronic heat stress (32 C) environment or a control (21C) environment from 4 to 8 wk of age. Body weight, BW gain, feed consumption, and feed efficiency were calculated at 4, 6, and 8 wk. The 32 C environment significantly reduced gain and feed consumption at all age intervals in both populations. Feed conversion ratio (FCR) was lower in the 32 C environment in the ACRB population, but in the broiler population FCR either was the same or increased when compared with the 21 C environment. In the F2 generation of both populations the naked neck birds were significantly larger than the normally feathered birds although the two types segregated from the same parents. In the ACRB population the relative growth response was not significantly different between naked neck and normal feathered birds, indicating that the Na gene did not confer resistance to chronic heat stress in the small BW population. In the broiler population, an assessment of the relative growth response in the 32 C environment showed that the naked neck birds had a smaller reduction in BW gain and better feed efficiency than the normally feathered birds, indicating that in the large BW broiler population the Na gene did confer resistance to chronic heat stress.

Cropping Systems Effects on Mycorrhizal Colonization, Early Growth, and Phosphorus Uptake of Corn

AbstractA field study was established in 1986 on a Viborg silty clay loam (fine‐silty, mixed, mesic Pachic Haplustoll) soil in eastern South Dakota. The objectives were to quantify the influence of crop rotation, tillage, and residual P (254 kg P ha−1 applied in fall 1985) on the incidence of vesicular‐arbuscular mycorrhizae (VAM) of corn (Zea mays L.) and to define the relationship between VAM colonization, early growth response to P, and early P uptake of corn. Plant and root samples were collected periodically from plots that varied in tillage and previous crop. Crop rotation and tillage influenced the early growth and P uptake of corn. Large differences in early growth response to P were observed among cropping systems. Average relative growth response as compared with the check during both years ranged from 360% for the moldboard (MP) corn‐fallow rotation to 7% for the ridge‐plant (RP) corn‐soybean (Glycine max [L.] Merr.) rotation. Early dry‐matter production and P uptake in the check plots were highest in the RP corn‐soybean system and lowest in the MP corn‐fallow system. Generally, VAM colonization rates were significantly higher (P ≤ 0.10) in the RP systems than in the MP systems. Considerable reduction in VAM colonization rates were found with P fertilization (P ≤ 0.01) in all cropping systems. An inverse relationship was measured between VAM colonization and relative early growth response to P (Y = 647.0 − 49.4X + 0.97X2; R2 = 0.92; Y = growth response in percent, X = percent root length colonized). Considering early dry‐matter production, P uptake, and mycorrhizal association the RP corn‐soybean system appears to provide a good environment for P nutrition of corn during early vegetative growth.

Sink Manipulation in Wheat: Compensatory Changes in Kernel Size

Kernel size (KS), an important yield component of wheat (Triticum aestivum L.), depends on assimilate availability and the capacity of the kernel to use assimilates. The objective of this study was to evaluate the response of wheat cultivars with different KS (20 to 43 mg kernel −1,) to sink manipulation. Twenty cultivars grown at two locations were partially degrained by removal of all spikelets from one side of only one spike per plant. Control spikes were left intact. Partial degraining decreased kernel number (KN) by 51%. Relative compensatory kernel growth tended to increase with decreasing KS. However, the KS of five cultivars was unaffected by partial degraining, and the relative growth response of one small‐ and one large‐kernel cultivar each deviated markedly from the predicted response. Partial degralning enhanced kernel N of all cultivars, with an estimated 19 to 80% of the increase in KS attributed to greater accumulation of N compounds. For selected caltivars, the KS distribution and flag‐leaf abscisic acid (ABA) were determined to evaluate the relationship of sink size to these traits. Partial degraining altered KS distributions; for all but one of seven cultivars evaluated, partially degrained cultivars had the largest 5% of kernels and the single largest kernel. Compensatory kernel growth was unrelated to flag‐leaf ABA, indicating partial degraining had no adverse effects on assimilate supply related to excessive ABA levels in the flag leaf. These results demonstrate variable cultivar response to partial degraining; apparently, kernel growth of some cultivars is source limited, while other cultivars are at their capacity to accumulate assimilates.

A flow cytometric approach to assessing the environmental and physiological status of phytoplankton.

Individual particle analysis using a flow cytometer (FCM) was made on natural phytoplankton communities in oligotrophic waters. Our objective was to develop an assay to yield information on the nutrient history of individual cells using FCM. Results from nutrient assays showed that both biovolume and total red fluorescence are affected by the nutrient conditions in the incubator. The light effect was measured by changes in the chlorophyll content of the cells, and after the 12 h incubation the cells seemed well adapted to the light conditions. The estimated kinetic constant for the chlorophyll synthesis averaged 1.5 x 1.0(-2) h-1, whereas the growth rate calculated from the changes in the cell numbers changed from 0.14 to greater than 2.5 doubling per day. The smallest size fraction presented the highest growth rate (greater than 2.5 doublings per day). The relationship between the total red fluorescence as estimated with the FCM and the biovolume revealed that the cells from the 2 m samples at the beginning of the experiment were probably nutrient limited. Important changes in the size of the cells under nutrient limitation were also observed. The FCM data suggest that the FCM is a valuable tool for estimating the relative growth response and nutritional state of natural phytoplankton populations.

Growth Patterns and Conformation in Broilers: Influence of Genotype and Management on Isometry of Growth

Log-linear regression equations of log-transformed weekly broiler growth data and allometric growth equations (in actual measure) were fitted with body weight as the predictor variable and shank length, keel length, breast width, and thigh width as response variables. Data were obtained on two commercial broiler genotypes (G1 and G2) reared on litter floor and in wire cages. Growth of each of the structural body components relative to growth of the body as a whole during a 12-wk growth period was similar in both cage and floor-reared groups. Analysis of the 12-wk pooled data from both cage and floor groups indicated the occurrence of isometric growth of the shank and breast in G1 and of the breast only in G2 and allometric growth of the thigh and keel in both genotypes. When starter and finisher growth phases were considered separately, data showed growth patterns generally similar to those of the different body parameters in the 12-wk period. This suggests that characterization of individuals on the basis of relative growth response for selection purposes can be done equally accurately during any phase of growth.

The influence of duration-of-inundation on development of a man-initiated Spartina alterniflora Loisel. Marsh in north carolina

The relative growth responses of a man-initiated Spartina altemiflora Loisel. marsh were monitored annually in four duration-of-inundation zones (4, 7, 9, and 11 h daily) during a 4-yr period following the 17-month establishment period, with another sampling 10 yr later. There was a general trend of maximum values for height, number of flowers · m −2, basal area, and aboveground standing crop to occur in the 7-h inundation zone and for these values to decrease in the 9- and 11-h zones at the end of the second growing season (17 months after planting). This trend was reversed from the third through the fifth growing seasons with height, number of flowers · m −2, and aboveground standing crop significantly higher in the longest (11-h) inundation zone. Although other angiosperms began invading the upper elevation, lesser inundated zones during the second growing season, populations were too small to sample until the following growing season (29 months after planting), when they constituted ≈40% of the aboveground standing crop in the uppermost (4-h) zone. The aboveground standing crop of the S. alterniflora-dommated 11-h inundation zone became stabilized by the third growing season, but the belowground material dry weight continued to increase in all zones through the fifth season when its rate of accumulation began to stabilize in the lowermost zones. Although the uppermost zone was dominated by Phragmites communis Trin. by the twelfth season, Spartina alterniflora dominated the other zones where it constituted more than three-fourths of the aboveground standing crop and had spread ≈ 30 m beyond the planting toward the open water of the estuary. The number of invading species present in the fifth season decreased by > 65% in the twelfth season, but the remaining invaders generally constituted relatively more of the aboveground standing crop by the twelfth season. Over the 12 seasons the experimental S. alterniflora planting developed into a marsh with the species composition dictated by the availability of disseminules of other angiosperms under the prevailing environmental conditions of duration-of-inundation and salinity.

Stimulation of mammary epithelial cell growth in vitro: interaction of epidermal growth factor and mammogenic hormones.

A serum-free primary cell culture system was used to examine the direct effects and interactions of mammogenic hormones and epidermal growth factor (EGF) on the growth of mouse mammary epithelial cells. Epithelial cells were isolated by collagenase dissociation followed by Percoll gradient centrifugation and cultured within collagen gels in a mixture of Ham's F-12-Dulbecco's Minimum Essential Medium (1:1) containing insulin (10 micrograms/ml), crude soybean lecithin, trace elements, trypsin inhibitor, and antioxidants. Progesterone (P; 10(-6) - 10(-8) M) or ovine PRL (1 microgram/ml), in the absence of EGF, stimulated the growth of cells from mature virgin mice 2- to 4-fold over that of controls cultured in basal medium only. P and PRL synergized in stimulating growth 3- to 17-fold. 17 beta-Estradiol (10(-7) - 10(-10) M) alone did not stimulate growth or synergize with P and/or PRL. This lack of growth stimulation by 17 beta-estradiol was also observed in medium containing a low concentration of insulin (0.1 microgram/ml). EGF (10 ng/ml) alone stimulated growth to the same extent as the combination of P and PRL. EGF at 1, but not 10, ng/ml when combined with P and PRL could additively stimulate growth. Cells from midpregnant mice were less responsive than cells from virgin mice to the growth-stimulating effects of the combination of P and PRL (2-fold stimulation at most), but not to EGF (3- to 6-fold stimulation). Corticosterone, deoxycorticosterone, and aldosterone, but not cortisol, could synergize with PRL in stimulating the growth of cells from mature virgin mice. However, only deoxycorticosterone could stimulate growth in the absence of PRL. These results suggest that PRL, P, and adrenal corticoids may directly stimulate the growth of mouse mammary epithelial cells. The physiologically relevent adrenal corticoids, corticosterone and aldosterone, only potentiate the stimulatory effect of PRL. The hormonal stimulation of growth in vitro can be obscured by an optimum concentration (10 ng/ml) of EGF. The relative growth responses to mammogenic hormones and EGF may depend on the degree of differentiation of the cells.

Sensitivity of boreal forests to possible climatic warming

General circulation models indicate substantial CO2 warming in high latitudes. In these regions, which include the boreal coniferous forests, the activity of ecosystems is largely controlled by temperature. The effective temperature sum (degree-days) is used in this study for describing the regional variability in the productivity of boreal ecosystems. Although the concept is simple, it takes into account two basic factors: the length of the growing season and the day-to-day level of activity of the ecosystem. This study examines which areas in the boreal coniferous forests would be most sensitive to a possible climatic warming. The data used in the study are for Finland.A regression is estimated between regional forest growth rate and effective temperature sum. A climatic warming is assumed and the corresponding growth response is calculated, using the regression, for northern and southern areas, and for maritime and continental areas. The response is expressed in terms of (i) absolute increase in growth (grams per m2 per year) and (ii) relative increase in growth. The results indicate that a given climatic warming would yield the greatest absolute increase in growth in warm (i.e. southern) and maritime parts of the biome. In terms of the relative growth response the sensitivity would increase northward and toward maritime areas.

Compensatory adrenal growth and conditioned avoidance response in relation to oestrous cycle and metoclopramide induced constant dioestrus.

The purpose of this study was to examine the relationship, between the hypothalamo-pituitary adrenal axis (H.P.A.A.) response to unilateral adrenalectomy (U.A.) and the two way active avoidance response, in rats with oestrous cyclicity and in rats with metoclopramide (MCP) induced constant dioestrus. MCP was used in a dosage that stimulates prolactin release through blockade of dopaminergic receptors (Carlson et al. 1977). The compensatory adrenal growth (C.A.G.) expressed by the difference in weight of the right adrenal, removed under ether anaesthesia, from the left adrenal, removed ten days postoperatively at autopsy, was considered an approximate index of the individual response to U.A. in each animal. Female Wistar rats (under 14h light 10h dark schedule) received for 10 days twice daily a s.c. injection of saline (SA) or MCP 3mg/kg body weight, starting 30 min before right unilateral adrenalectomy (U.A.) under ether anaesthesia. The weight of the removed right

Androgen receptor specificity and growth response in Shionogi carcinoma cells.

Shionogi mouse tumor cells were cultured in the presence of various androgens and androgen derivatives to determine their growth response in relation to nuclear binding of androgen receptor; cells maintained in medium containing the physiological androgens testosterone and 5α-dihydrotestosterone (DHT) exhibited a marked increase of thymidine incorporation. Other steroids were found to be less effective or non-effective. Receptor-bound hormone could be extracted from the nuclei after incubation of intact cells with [ 3 H]-labeled 5α-DHT. This nuclear localization of receptor appeared to be one of the factors controlling the growth of Shionogi cells since a correlation was found between the magnitude of the growth stimulation and the intranuclear concentration of receptor-bound hormone.

The effect of acid precipitation on tree growth in eastern North America

Detailed study of the history of forest tree growth by tree-ring analysis is used to assess the effect of acid precipitation. The pattern and historical trends of acid precipitation deposition are compared with growth trends from mature forest stands in New Hampshire and Tennessee. No clear indication of a regional, synchronized decrease in tree growth was found. The residual variation of relative tree growth responses, after removal of variation due to weather, shows no recent time-dependent trend. Due to the unknown initiation date of acid precipitation and to the large variation of tree growth estimates, a correlation of forest growth and acid precipitation in eastern North America cannot be established at the present time.

Heterotrophic growth of filamentous blue-green algae

A survey has been made of the growth response shown by 20 filamentous blue-green algal strains to the presence of organic substrates in the medium. Six strains showed no growth in the dark in the presence of any substrate. Among the other 14 strains, relative growth response to added substrates often fell in relation to the sequence: sucrose > fructose > glucose > maltose. The 20 strains can be classified according to their ability to make use of added 0·01 m sucrose. The different categories include: negligible increase in growth under any circumstances; photoheterotrophic growth only; photoheterotrophic growth + survival in dark; photo-heterotrophic + chemoheterotrophic growth. Three of the strains capable of chemoheterotrophic growth are more restricted in the dark than in the light with respect to the nitrogen sources they can use.

PHOSPHATE ABSORPTION BY PLANTS FROM HABITATS OF DIFFERENT PHOSPHATE STATUS

Summary Deschampsia flexuosa and Scabiosa columbaria, species with low relative growth rate and small growth response to phosphate concentration contain a greater proportion of inorganic phosphate than organic phosphate. By contrast, Urtica dioica and Rumex acetosa with high relative growth rates and high phosphate response contain more organic phosphate, particularly organic insoluble phosphate, especially when grown in low phosphate concentrations. It is concluded that the evidence from the present and previous work indicates that the growth response to phosphate is a reflection of relative growth rate, that is, demand for phosphate in growth.

Relative growth responses of previously depleted male and female rats to vit. A supplementation.

SummaryMale rats which have been depleted of their body reserve of vit. A grow more during a 28-day test period than do corresponding female rats when a daily dosage of 2.0 U.S.P. units or more of the vitamin is fed as the supplement. This increased growth is not directly related to the body weight of the test animal at the beginning of the supplementary feeding period. While it appears that the greater growth capacity is an inherent characteristic of the male rat which is present at the beginning of the test period, it is not clear as to why this characteristic does not manifest itself at all levels of vit. A intake.

Comparative growth cycles of Endamoeba histolytica with different combinations of bacteria.

Summary 1. The mixed bacterial flora accompanying our culture of the NRS strain of E. histolytica was analyzed into its components: Escherichia coli communior (NRS-I), E. coli anaerogenes (NRS-IA), and an unnamed paracolon bacillus (NRS-II). 2. A series of monobacterial cultures were established by chemical treatment of cysts with 1:50,000 mercuric chloride for 90 minutes at 4°C. 3. E. histolytica was established separately with the following bacteria in aqueous eggyolk infusion: NRS-II, NRS-I, Aerobacter aerogenes, E. coli communis, Proteus vulgaris, Aerobacter cloacae, Kurthia zenkeri, Streptococcus equinus, S. faecalis, and S. liquefaciens. 4. Populations of bacteria and amebas were plotted in the form of growth curves for the first six types listed above, with the relative growth response of the amebas in the same order as the above list. No correlation could be observed between the relative ranking of bacterial and amebic growth, and within rather wide limits no controlling influence of inoculum could be determined. 5. The highest growth response of the amebas was obtained with the original mixed flora.

Relative Growth Response of Crops to Each Fertilizer Ingredient and the use of This Response in Adapting a Fertilizer Analysis to a Crop1

Agronomy JournalVolume 13, Issue 9 p. 353-359 Article Relative Growth Response of Crops to Each Fertilizer Ingredient and the use of This Response in Adapting a Fertilizer Analysis to a Crop1 Burt L. Hartwell, Burt L. Hartwell Director and agronomist, Agricultural Experiment Station of Rhode Island State College.Search for more papers by this author Burt L. Hartwell, Burt L. Hartwell Director and agronomist, Agricultural Experiment Station of Rhode Island State College.Search for more papers by this author First published: 01 December 1921 https://doi.org/10.2134/agronj1921.00021962001300090003x 1 Presidential address of the Society for the Promotion of Agricultural Science. Presented at a joint session of that Society and the American Society of Agronomy at New Orleans, La., November 8, 1921. Contribution 284 of the Agricultural Experiment Station of Rhode Island State College, Kingston, R. I. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume13, Issue9December 1921Pages 353-359 RelatedInformation