Greatest Increase In Growth Research Articles

Effects of antagonistic fungi and plant growth-promoting rhizobacteria on growth of tomato and reproduction of the root-knot nematode,Meloidogyne incognita

The effects of antagonistic fungi (Paecilomyces lilacinus, Pochonia chlamydosporia and Trichoderma harzianum) and plant growth-promoting rhizobacteria (PGPR), namely Bacillus subtilis, Paenibacillus polymyxa and Burkholderia cepacia, were studied alone and in combination in glasshouse experiments on the growth of tomato and on the reproduction of the nematode Meloidogyne incognita. Application of antagonistic fungi and PGPR caused a significant (P < 0.05) increase in tomato growth (based on shoot dry weight) both with and without nematodes. P. lilacinus was more effective in reducing galling and improving the growth of nematode-inoculated plants than T. harzianum, while P. polymyxa was more effective than B. subtilis. The greatest increase in growth of nematode-inoculated plants and reduction in nematode galling was observed when P. polymyxa was used with P. lilacinus or P. chlamydosporia. P. lilacinus parasitised more females and eggs than the other fungi tested. Root colonisation by P. polymyxa was high when used alone but reduced in the presence of antagonistic fungi.

Protein and energy utilization and the requirements for maintenance in juvenile mulloway (Argyrosomus japonicus)

This study describes the digestible protein (DP) and digestible energy (DE) utilization in juvenile mulloway, and determined the requirements for maintenance. This was achieved by feeding triplicate groups of fish weighing 40 or 129 g held at two temperatures (20 or 26 degrees C), on a commercial diet (21.4 g DP mJ DE(-1)) at four different ration levels ranging from 0.25% of its initial body weight to apparent satiation over 8 weeks. Weight gain and protein and energy retention increased linearly with increasing feed intake. However, energy retention efficiency (ERE) and protein retention efficiency (PRE) responses were curvilinear with optimal values, depending on fish size, approaching or occurring at satiated feeding levels. Maximum predicted PRE was affected by body size, but not temperature; PRE values were 0.50 and 0.50 for small mulloway, and 0.41 and 0.43 for large mulloway, at 20 and 26 degrees C respectively. ERE demonstrated a similar response, with values of 0.42 and 0.43 for small, and 0.32 and 0.34 for large mulloway at 20 and 26 degrees C respectively. Utilization efficiencies for growth based on linear regression for DP (0.58) and DE (0.60) were independent of fish size and temperature. The partial utilization efficiencies of DE for protein (k (p)) and lipid (k (l)) deposition estimated using a factorial multiple regression approach were 0.49 and 0.75 respectively. Maintenance requirements estimated using linear regression were independent of temperature for DP (0.47 g DP kg(-0.7) day(-1)) while maintenance requirements for DE increased with increasing temperature (44.2-49.6 kJ DE kg(-0.8) day(-1)). Relative feed intake was greatest for small mulloway fed to satiation at 26 degrees C and this corresponded to a greater increase in growth. Large mulloway fed to satiation ate significantly more at 26 degrees C, but did not perform better than the corresponding satiated group held at 20 degrees C. Mulloway should be fed to satiation to maximize growth potential if diets contain 21.4 g DP mJ DE(-1).

Impact of DOM from composted “alperujo” on soil structure, AM fungi, microbial activity and growth of Medicago sativa

Water-soluble extracts from compost may represent an alternative nutrient and organic matter source for crop production under drip irrigation. Dissolved organic matter (DOM), extracted from composted "alperujo", the main by-product from the Spanish olive oil industry, was applied to soil alone or in combination with either Glomus intraradices Schenck and Smith or a mixture of G. intraradices, Glomus deserticola (Trappe, Bloss. and Menge) and Glomus mosseae (Nicol and Gerd.) Gerd. and Trappe. Response measurements included mycorrhizal colonisation, nutrient uptake and growth of Medicago sativa and microbiological and physical properties in the rhizosphere. Dissolved organic matter was added to soil at concentrations of 0, 50, 100 or 300mgCkg(-1) substrate. During the four months of the experiment, the plants were harvested three times. Both mycorrhizal inoculation treatments significantly increased soil aggregate stability. Only the mycorrhizal inoculations increased microbial biomass C and protease and phosphatase activities and decreased water-soluble C, particularly the mixture of arbuscular mycorrhizal fungi. At the third harvest, the greatest increase in growth of M. sativa was observed in the inoculated plants with shoot biomass being 38% greater than for plants grown in the soil amended with the highest dose of DOM and 57% greater than for control plants. The addition of DOM was not sufficient to restore soil structure and microbial activity and did not affect the mycorrhizal development of introduced populations of arbuscular mycorrhizal fungi, but, depending on the dose, its fertiliser efficiency for improving plant growth was apparent.

Effects of management intensity, genetics and planting density on wood stiffness in a plantation of juvenile loblolly pine in the southeastern USA

In a 6-year-old plantation of Pinus taeda in Northeast Florida, the affects on juvenile corewood stiffness of genotype, planting density and silviculture as well as their interactions, and some potential mechanisms for these effects were investigated. The stress wave method was used to determine the dynamic modulus of elasticity ( V 2) of the juvenile corewood in 4091 standing trees of seven full-sib families grown at two planting densities (1334 trees ha −1 versus 2990 trees ha −1) with two levels of silvicultural intensity (operational versus intensive). Planting density significantly influenced V 2 ( p < 0.0001) across all families and silvicultural intensities. At 2990 trees ha −1, V 2 averaged 7.11 and 5.44 km 2 s −2 for 1334 trees ha −1. Family and silvicultural intensity interacted significantly for V 2 ( p = 0.0003) with values ranging from 5.03 to 7.48 km 2 s −2. Under intensive silviculture, one family (L1) exhibited a large decrease in V 2. In contrast, another family (L4) with a high overall V 2 rank was not very sensitive to silvicultural treatment intensity. This lack of response under intensive silviculture occurred despite the fact that family L4 demonstrated the greatest increase in growth. Across all treatments, the ratio of height to diameter at breast height (HT:DBH) was strongly related to V 2 with more slender trees being the stiffest. After adjusting for this ratio, only the main effects of initial planting density and genotype were significant. Thus, HT:DBH correlated with variation in V 2 caused by silvicultural intensity. In a subset of trees within three selected families, variation in latewood percentage (LWP) did not correlate with variation in V 2 as predicted. Analysis of the treatments on LWP, showed a significant three-way interaction between genotype, planting density, and silvicultural intensity. Surprisingly, the LWP of a single family (L4) responded differently to silvicultural treatment under contrasting planting densities. Findings from this study indicate that considerable opportunity exists to improve corewood stiffness in juvenile loblolly pine plantations through the deployment of selected genotypes in combination with appropriate initial planting density and silvicultural intensity.

Effects of mulching and insecticides on establishment and growth of Norway spruce

Establishment of Norway spruce (Picea abies (L.) Karst.) seedlings is often restricted by competition from vegetation, drought, and damage by pine weevils. In this study, effects of mulching on these factors were investigated. Norway spruce seedlings were planted on fresh and 1-year-old clearcuts treated with mulch on three sites in southern Sweden. Mulch was made of slash from the old stand and applied on whole blocks at three different depths: 0, 10, and 20 cm. Both insecticide-treated and untreated seedlings were planted. By reducing the competing vegetation and improving soil moisture and mineralization, mulching created a favorable growth environment. Mulching significantly improved growth in terms of height, diameter, and volume of the seedlings. Growth continued to increase over time in mulched treatments, probably as an effect of increased nutrient availability. The 20 cm mulch layer generated the greatest increase in growth throughout the 10-year experimental period. Soil moisture was preserved under the isolating mulch layer and during periods of drought soil water potential was significantly higher in mulched treatments. After 2 years, percent cover of competing vegetation was 50%–60% without mulch and 10%–20% with a mulch depth of 20 cm. Insecticide-treated seedlings achieved a survival rate close to 100% in all mulching treatments, whereas survival among untreated seedlings was only 40% on some clearcuts. Mulching alone did not affect survival or abundance of pine weevils.

(39) Determination of the Optimum Species for Ohio Tree Liner Production in Retractable Roof Greenhouses

Many Ohio growers import liners from the West Coast due to the increased growing season on the West Coast. Lengthening the season in Ohio may provide a way for Ohio growers to produce liners of their own. Retractable roof greenhouses (RRG) are one possible way to extend the growing season in Ohio. Research done previously at The Ohio State University suggests that retractable roof greenhouses do in fact lengthen the growing season, and tree liners can be produced using RRG. The objectives of this study were: 1) to determine the optimal growing environment from three different environments; and 2) to determine the optimal species for tree liner production in Ohio. In Oct. 2004, 180 liners each of Cladrastis kentuckea, Quercus rubra, Stewartia pseudocamellia, Syringa reticulata, and Tilia cordata were upshifted to 3-gallon pots. In Mar. 2005, 90 of each species were transferred to either a flat roof retractable house (FRRG), peak roof retractable house (PRRG), or polyhouse. Growth was measured in Mar. (initial), June, Aug., and Oct. 2005 by taking leaf area, shoot and root dry weights, height, and caliper. There were no differences across species and dates between the environments for any of the parameters measured. Tilia showed the greatest increase in growth from June to October in all the parameters measured except leaf area. Cladrastis showed the greatest increase in leaf area from June to October. There were species by date interactions. Quercus had the greatest root weight in October. Syringa and Quercus were not significantly different from each other and had the highest shoot weights and leaf areas in October. Tilia, Quercus, and Syringa had the highest calipers in October.

Combined Effects of Elevated Co2and Herbivore Damage on Alfalfa and Cotton

We examined herbivore-induced responses of alfalfa (Medicago sativa) and cotton (Gossypium hirsutum) under different CO2 conditions. Plants were grown under ambient (350 ppm) or elevated (700 ppm) CO2 levels, and were either damaged or undamaged by Spodoptera littoralis larvae. At harvest, growth of undamaged (control) plants was determined, and foliar chemical composition of both undamaged and damaged plants was analyzed. Cotton grew faster overall and showed a greater increase in growth in response to CO2 enrichment than did alfalfa. Elevated CO2 levels increased starch and decreased nitrogen levels in damaged alfalfa and undamaged cotton plants. Alfalfa saponin levels were significantly increased by elevated CO2 and damage. Regarding specific saponins, medicagenic acid bidesmoside (3GlcA,28AraRhaXyl medicagenate) concentrations were reduced by high CO2, whereas zanhic acid tridesmoside (3GlcGlcGlc,23Ara,28AraRhaXylApi Za) levels were unaffected by the treatments. Soyasaponin I (3GlcAGalRha soyasapogenol B) was only detected in minute amounts. Alfalfa flavonoid analyses showed that total flavonoid levels were similar between treatments, although free apigenin increased and apigenin glucoside (7-O-[2-O-feruloyl-beta-D-glucuronopyranozyl (1-->2)-O-8-D-glucuronopyranozyl]-4'-O-beta-D-glucuronopyranozide apigenin) decreased in CO2-enriched plants. In cotton, herbivore damage increased levels of total terpenoid aldehydes, gossypol, hemigossypolone, the heliocides H1 and H4, but not H2 and H3, whereas CO2 enrichment had no effect. These results demonstrate that combined effects of CO2 and herbivore damage vary between plant species, which has implications for the competitive balance within plant communities.

Effects of soil inoculants on the growth, transpiration and wilt disease of chickpea

Glasshouse experiments were conducted twice to assess the effects of soil inoculants (Rhizobium sp., Glomus fasciculatum and Trichoderma harzianum) and wilt fungus Fusarium oxysporum f. sp. ciceri on growth and transpiration of chickpea. Inoculation of F. oxysporum f. sp. ciceri reduced plant growth, transpiration and caused severe wilting. Application of Rhizobium sp., G. fasciculatum and T. harzianum alone or in combination increased chickpea growth of F. oxysporum f. sp. ciceri-inoculated plants and also increased transpiration from 1st week onwards. However, T. harzianum alone had no effect on growth and transpiration of chickpea in plants without F. oxysporum f. sp. ciceri while Rhizobium and G. fasciculatum increased growth and transpiration from 1st week onwards. Use of T. harzianum alone caused a greater increase in growth and transpiration of F. oxysporum f. sp. ciceri inoculated plants than Rhizobium. Better growth and more transpiration of F. oxysporum f. sp. ciceri-inoculated plants was observed when all the three soil inoculants were applied together. This also resulted in lowest wilting index, higher root nodulation and greater root colonization by G. fasciculatum.

Some Nutritional Factors Affecting Production of Biomass and Antifungal Metabolites of Coniothyrium minitans

The ability of the mycoparasite Coniothyrium minitans to utilize a range of C and N sources and vitamins for growth, pycnidial formation and antifungal metabolite production was examined using a defined liquid medium. Coniothyrium minitans was able to use all the C sources tested, with the exception of D -xylose, and all the N sources tested, although growth was generally better on organic N sources rather than NO 3 -N. Increasing C:N ratios from 9:1-202:1 with N constant (2.0 g L -l L -alanine) resulted in steadily increasing yields, whereas increasing C:N ratios with C constant (40.0 g L -l D -glucose) gradually decreased yield. Addition of thiamine to the glucose-alanine basal medium resulted in the greatest increase in growth but biomass was still less than that achieved using an undefined molasses-yeast medium. Pycnidial production was generally low or failed to occur in the basal medium + C + N sources in the absence of vitamins, but addition of thiamine consistently led to abundant pycnidial formation. Molasses-yeast static culture provided greater biomass and conidial yields than molasses-yeast shaken culture. Incorporation of C. minitans culture medium into potato dextrose broth (10% v/v) resulted in consistent reduction in growth of Sclerotinia sclerotiorum irrespective of C, N or vitamin content of the basal medium or whether molasses-yeast medium was used. This is the first report of consistent production of antifungal metabolites by C. minitans .

Association between growth, body condition and anti‐predator behaviour in maturing and immature brown trout parr

In spring there were significant differences between maturing and immature brown trout Salmo trutta in anti‐predator behaviour to pike and heron models when all behaviours were combined in multivariate analysis. However, the time until the trout visited the patch in the experimental tray where predators attacked was the only variable that alone significantly differed between maturity groups; following transfer between the rearing tank and the experimental tray, maturing fish visited this patch sooner. The difference in anti‐predator behaviour coincided with differences developing between the groups in both growth rate and condition factor. Maturing fish showed higher growth rates and exceeded immature fish in condition factor from spring onwards. In a summer experiment, no differences in anti‐predator behaviour were observed between maturing and immature fish. It is concluded that increased risk‐taking to facilitate higher food intake is probably the behavioural mechanism responsible for the comparatively greater increases in growth and body condition observed among maturing fish in spring.

Effect of nursing mixtures on stem form, crown size, branching habit and wood properties of Sitka spruce ( Picea sitchensis (Bong.) Carr.)

This study investigated the effects of Alaskan lodgepole pine ( Pinus contorta Loud.) and hybrid larch ( Larix × eurolepis Henry) nurses, planted in triplet mixture with Sitka spruce ( Picea sitchensis (Bong.) Carr.), on growth rate, stem form, branching habit and wood properties of the spruce. These mixtures were compared with pure stands of Sitka spruce which had been regularly and periodically fertilised with nitrogen. Hybrid larch promoted diameter increments in Sitka spruce greater than those achieved by the other treatments over the last 12 years of the experiment (current age 30 years). Growth of regularly fertilised pure Sitka spruce was not significantly greater than that of periodically fertilised pure spruce, suggesting that regular applications of nitrogen fertiliser did not result in increased stem growth. The greatest increase in growth of the larch-nursed spruce occurred during the period immediately following canopy closure, thus demonstrating the failure of the larch to compete with the spruce crowns. This period of high growth was associated with a high branch, cross-sectional area and deep knots within the wood on the lower part of the spruce stems in comparison with other treatments. While each treatment was associated with a similar number of branches, lodgepole pine-nursed spruce had more small branches (0–10 mm diameter) and fewer big branches (>20 mm diameter) compared with other treatments, highlighting the capacity of lodgepole pine to control branch development of the spruce. Spruce trees nursed by larch had deeper and more imbalanced living crowns with longer lived branches in comparison with lodgepole pine-nursed spruce, and both the pure spruce treatments, suggesting that more juvenile wood may have formed within the stem. Larch-nursed spruce also had the highest stem taper and lodgepole pine-nursed spruce the lowest. Basic wood density was not influenced by treatments. Overall, the evidence from this study suggests that the use of larch as a nursing species on deep peats is inadvisable and that Alaskan lodgepole pine is better able to control the branching habit of Sitka spruce with the prospect of better quality sawlogs in the future, albeit with a lower average tree size. Periodically fertilised pure spruce appears to maintain a growth rate consistently above that of the lodgepole pine-nursed spruce but without many of the disadvantages linked with the regularly fertilised pure spruce, particularly the development of large branches and an irregular pattern of annual rings within the wood.

Ethylene-insensitive tobacco lacks nonhost resistance against soil-borne fungi: Knoester M, van Loon LC, van den Heuvel J, Hennig J, Bol JF, Linthorst HJM: Proc Natl Acad Sci USA 1998, 95:1933–1937

Ethylene is involved in various aspects of plant growth and development. We studied ethylene sensitivity in four mustard (Brassica juncea L. Czern and Coss.) cultivars, Pusa Jai Kisan, Alankar, Basanti and SS2 using chemicals that modify ethylene production and examined its role in determining photosynthesis and growth. Pusa Jai Kisan showed maximum sensitivity to ethylene and was more responsive to ethylene modulators than SS2, which exhibited minimum sensitivity to ethylene. In the presence of ethephon (ethylene-source), Pusa Jai Kisan exhibited greatest increase in growth and the activity of ribulose-1,5-bisphosphate carboxylase (Rubisco), net photosynthesis, stomatal conductance and intercellular CO2 concentration, and maximal decrease in these characteristics with ethylene action inhibitor, norbornadiene (NBD). Glucose treatment did not inhibit Rubisco activity, net photosynthesis and growth in ethylene-sensitive plants, but these characteristics were maximally inhibited in ethylene-insensitive plants. Our results show that ethylene sensitivity has a role in determining photosynthesis and growth of mustard plants. The selection of an ethylene-sensitive mustard type would help in augmenting photosynthesis and growth and also provide new insight into the ethylene-mediated physiological responses.

Carbohydrate reserves and CO 2 balance of hybrid walnut ( Juglans nigra no. 23 X Jugions regia) plantlets during acclimatisation

Morphological and physiological characteristics of hybrid walnut plantlets were studied during acclimatisation in growth chambers. The study was conducted on two clones, M41 and D152. At the end of the in vitro phase, D152 had produced more adventitious roots but less leaves than M41. M41 accumulated more soluble sugars and starch than D152. During acclimatisation, the greatest increase in growth occurred in root length, regardless of the clone studied. However, the dry matter and carbon contents were always higher in M41 than in D152. The morphology of rooted plantlets differed markedly from that of young seedlings. During the first 7 days of acclimatisation, the balance of CO 2 exchange on a daily basis was negative (respiration was dominant). During this period, the carbohydrates which accumulated chiefly in the roots and callus during the root development phase were used for growth and maintenance processes. The balance of CO 2 exchange (on a daily basis) became positive after this heterotrophic phase. The new leaves formed during the acclimatisation phase appeared to be actively involved in the acquisition of autotrophy. At the end of the acclimatisation phase, the carbohydrate content of all organs was very low and the plantlet was dependent on photosynthesis. The capacity of hybrid walnut clones to survive the acclimatisation phase is discussed.

Glucose modulates growth of gingival fibroblasts and periodontal ligament cells: correlation with expression of basic fibroblast growth factor.

Diabetes mellitus is a systemic disease with profound effects on oral health and periodontal wound healing. Uncontrolled diabetes adversely affects surgical wound healing and is often associated with abnormal proliferation of fibroblasts, excessive angiogenesis and poor bone regeneration. Human gingival fibroblasts and periodontal ligament cells from both diabetics and non-diabetics were evaluated for growth responses following culture in 20 mM glucose, a concentration compatible with blood glucose levels in uncontrolled diabetics. Gingival fibroblasts derived from 9 non-diabetic patients and 3 insulin-dependent diabetics either proliferated or showed little change of growth in elevated glucose. Enhanced proliferation was observed following 1 wk of culture in glucose. Growth of periodontal ligament cells from 5 non-diabetic patients was inhibited by 20 mM glucose. Fibroblasts that were markedly growth stimulated were probed for expression of basic fibroblast growth factor (bFGF) using a reverse-transcribed polymerase chain reaction (RT-PCR). Results indicate that fibroblasts exhibiting the greatest increase in growth in response to high glucose also exhibited increased expression of bFGF. No changes were observed in mRNA expression for platelet-derived growth factor-AA, platelet-derived growth factor-BB, insulin-like growth factor and transforming growth factor-beta 1. Mitogenic effects induced by the cytosol of fibroblasts exhibiting increases of growth in 20 mM glucose were abrogated by neutralizing antibodies to bFGF. In addition, some periodontal ligament cells that were growth inhibited by high glucose had reduced expression of bFGF. These data suggest that bFGF may play a role in the abnormal wound healing associated with periodontal surgery of uncontrolled diabetics.

Influence of Nitrogen Fertilizers on Growth, Spore Production and Germination, and Biocontrol Potential of Trichoderma and Gliocladium

AbstractThe mycelial weight of eight out of nine isolates of Trichoderma spp. and Gliocladium virens increased in media supplemented with 2000 mg/l of nitrogen (N) from the fertilizers NH4Cl, NaNO3, and a commercial 20–20–20. In general, the greatest increase in growth (up to 311 %) occurred with 20–20–20. The extent of growth was similar with either NH4Cl or NaNO3, but was less than that with 20–20–20. Measured by radial development on agar surfacesgrowth of isolates was either not affected or was constricted by supplemental fertilizers. Production of conidia by six out of eight isolates was stimulated by 20–20–20 but not by NH4Cl or NaNO3. Germination of conidia of all isolates, generally was high (&gt; 85 %) on amended and nonamended agar. Chlamydospore formation by three Trichoderma isolates in liquid media was not affected by fertilizers. Antagonism or overgrowth of the pathogen Rhizoctonia solani by Trichoderma isolates in culture was reduced appreciably by NaNO3, but was not affected by NH4Cl or 20–20–20. Addition of 20–20–20 to natural soil did not reduce further the survival of R. solani caused by germling preparations of six out of seven Trichoderma isolates. However, reduction in survival of the pathogen caused by a T. hamatum isolate was stimulated further (45 %) by the fertilizer.

The results of introducing grass carp, Ctenopharyngodon idella Val., into small lakes

. Grass carp, Ctenopharyngodon idella Val., were introduced into three small lakes in the south Midlands, England to control submerged weeds. Control was variable, depending on the particular conditions in each lake, each year. After stocking at low density (61–130 kg/ha) grass carp were weighed annually, the greatest increase in growth being in Pusey Lake. In 4 years, their average weight increased from 85 g to 1250 g. In Shinrield Lake grass carp co-existed with a varied population of coarse fish and the weed problem was controlled satisfactorily. Zooplankton, temperature, dissolved oxygen and plant distribution records were kept. At Pusey greatest weed control was achieved when spring temperatures were high, but weed species re-appeared soon after the fish were removed.

Resistance of cultured higher plant cells to polyethylene glycol-induced water stress

Cell of tomato ( Lycopersicon esculentum Mill, cv. VFNT Cherry) capable of an enhancedability to grow in the presence of water stress were obtained by exposure of cultured cells to a medium containing polyethylene glycol. These cells exhibited a 14-fold greater increase in growth under stress compared to cells never exposed to polyethylene glycol. The increased resistance was stable when the cells were grown in the presence of polyethylene glycol but rapidly was lost when the cells were transferred back to a medium without the stress agent. Cells resistant to polyethylene glycol-induced water stress also showed increased resistance to NaCl. Adaptation is suggested as a likely mechanism by which resistance is increased.

Growth and plant zinc distribution in two navy bean varieties fertilized with zinc

Abstract Sanilac and Saginaw varieties of navy beans were grown on Wisner silty clay loam. Treatments of no added Zn and 3 ppm Zn were applied to the soil fertilized with N, K, and 500 ppm P. Selected plant tissues were harvested two, four, six, or eight weeks after planting. The weights and Zn contents of some tissues were not affected by Zn application regardless of variety but the growth of the plant parts above the primary leaves and the Zn contents of the trifoliolate leaves increased with Zn rate. The three oldest trifoliolate leaves and younger tissues showed equal or greater increases in growth and Zn contents than the total plant tops, but the primary leaves and the lower portions of stems were less influenced by available Zn in the soil. These responses indicated that the three oldest trifoliolate leaves were the most reliable indexes for available Zn throughout the growing period. As the plants matured, the growth and Zn contents of the young tissues of the Saginaw variety responded more to Zn ...

Effect of Barbituric Acid, Chlortetracycline and Carbohydrates upon Growth and Gastrointestinal Urease Activity of Chicks

Results are presented from 100 lots of 15 chicks/lot fed basal diets containing sucrose, dextrose or starch and supplemented with barbituric acid (1.28g/kg) or chlortetracycline (0.1 g/kg) alone or in combination. These supplements when added alone produced the greatest increase in growth with the sucrose diet and the smallest with the starch diet. The 2 supplements in combination did not show an additive effect. The efficiency of feed utilization followed that of growth. Gastrointestinal ammonia production and ureolytic activity were suppressed only when these was an observed increase in growth with the additives. Ureolytic activity in the small intestine was inversely related to the growth response of the various basal carbohydrate diets; however, lowest activity did not reflect greatest gain for all treatments. The response to barbituric acid, a cyclic urea compound, appears to be dependent on the carbohydrate sources, an observation similar to that noted with antibiotics.

Effect of Soil Temperature and Nitrogen Fertilization on the Growth of Soft Chess (Bromus mollis) at Two Elevations

SynopsisApplied nitrogen increased the growth rate of the grass very little when the average soil temperature was below 45° F. Grass fertilized with nitrogen showed the greatest increase in growth compared with unfertilized grass when the average soil temperature was between 47° and 55°. When the temperature went above 55° the difference between unfertilized and fertilized grass decreased.