scholarly journals Studies on the Feeding and Nutrition of Tuberolachnus Salignus (Gmelin) (Homoptera, Aphididae)

1958 ◽  
Vol 35 (3) ◽  
pp. 626-638
Author(s):  
T. E. MITTLER
Keyword(s):  
Nitrogen Balance ◽  
Leaf Development ◽  
Nitrogen Assimilation ◽  
Nitrogen Supply ◽  
Atmospheric Nitrogen ◽  
Phloem Sap ◽  
Dietary Nitrogen ◽  
Tuberolachnus Salignus

1. The investigation concerns the ingestion, excretion, and assimilation of dietary nitrogen by Tuberolachnus salignus (Gmelin) developing on Salix trees in various stages of leaf development. 2. Apterous and alate forms of T. salignus differ in their rates of development and nitrogen assimilation and in their behaviour. 3. The aphids assimilate considerably more nitrogen when developing on willows having a phloem sap rich in nitrogen than on willows having a phloem sap relatively poor in nitrogen. 4. For a given amount of nitrogen assimilated the aphids ingest a larger volume of a phloem sap poor in nitrogen than of a phloem sap rich in nitrogen. 5. Nitrogen balance experiments have shown that T. salignus nymphs assimilate only as much nitrogen as they are able to absorb from their food. 6. The evidence for and against the fixation of atmospheric nitrogen by aphids through the agency of their symbionts is briefly discussed. T. salignus do not supplement their dietary nitrogen supply by fixing atmospheric nitrogen.

Studies on the Feeding and Nutrition of Tuberolachnus Salignus (Gmelin) (Homoptera, Aphididae):

1957 ◽  
Vol 34 (3) ◽  
pp. 334-341
Author(s):  
T. E. MITTLER
Keyword(s):  
Host Plant ◽  
Sieve Tube ◽  
Normal Rate ◽  
Phloem Sap ◽  
Food Canal ◽  
Tuberolachnus Salignus ◽  
Normal Feeding ◽  
Sieve Tubes ◽  
Considerable Pressure ◽  
Salix Spp

1. A study has been made of the factors involved in the uptake of phloem sap by Tuberolachnus salignus (Gmelin) feeding on the stems of various Salix spp. 2. A method has been developed for maintaining the parthenogenetic viviparous forms of T. salignus in culture throughout the year. 3. It has been established that during normal feeding T. salignus have the tips of their stylets inserted into the phloem sieve-tubes of the host plant. 4. The phloem sieve-tube sap of intact and turgid willow stems is under considerable pressure. This pressure forces the sieve-tube mp up the stylet food canal of feeding aphids, and also causes the sieve-tube sap to exude for many hours from the cut end of embedded stylet bundles. 5. Intact and feeding T. salignus rely almost entirely on this pressure to maintain their normal rate of eieve-tube sap uptake. The aphids must, however, swallow actively in order to ingest.

EFFECT OF SULPHUR TREATMENTS ON YIELD AND NITROGEN AND SULPHUR CONTENT OF ALFALFA GROWN ON SULPHUR-DEFICIENT AND SULPHUR-SUFFICIENT GREY WOODED SOILS

1961 ◽  
Vol 41 (4) ◽  
pp. 709-715 ◽  
Author(s):  
R. R. Cairns ◽  
R. B. Carson
Keyword(s):  
Nitrogen Content ◽  
Relative Abundance ◽  
Nitrogen Assimilation ◽  
Calcium Sulphate ◽  
Nitrogen Supply ◽  
Physiological Functions ◽  
Root Nodulation ◽  
Main Effect ◽  
Sulphate Sulphur ◽  
Elemental Form

Sulphur applied in the elemental form, or as sodium or calcium sulphate, on Grey Wooded soils, increased yields of alfalfa on sulphur-deficient Loon River loam, but not on sulphur-sufficient Garrick loam. The quantity of sulphate-sulphur was extremely low in the alfalfa grown on untreated Loon River loam and increased markedly as a result of the application of sulphur to the soil. Although herbage from untreated areas of the sulphur-deficient soil contained a slightly higher per cent nitrogen in 1955 than that grown on the sulphur-sufficient soil, sulphur treatment increased nitrogen content and yield of nitrogen on the sulphur-deficient soil. The relative abundance of nitrogen in the herbage grown on the check areas of the deficient soil suggests that the main effect of sulphur was not on root nodulation or nitrogen supply, but rather on nitrogen assimilation and other physiological functions of the sulphur-containing compounds within the plant.

Aspects of nitrogen utilization in Asiatic water buffalo and Zebu cattle

1983 ◽  
Vol 100 (1) ◽  
pp. 13-23 ◽  
Author(s):  
J. B. Moran
Keyword(s):  
Nitrogen Balance ◽  
Water Buffalo ◽  
Energy Content ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Nitrogen Excretion ◽  
Zebu Cattle ◽  
Dietary Nitrogen ◽  
Faecal Nitrogen ◽  
Urinary Nitrogen

SUMMARYThe results of 62 comparative digestibility and nitrogen balance trials of Asiatic water buffalo and Zebu cattle fed the same roughage or mixed diet were analysed to test for species differences in various nitrogen input-output relationships. The influence of dietary metabolizable energy content on the utilization of dietary or apparently digested nitrogen (ADN) was also investigated.There was no difference between buffaloes and Zebus in their ability to digest dietary nitrogen. The true nitrogen digestibility was calculated to be 81% and the metabolic faecal nitrogen excretion to be 0·36 g N/lOOg dry-matter intake. The buffaloes had lower rates of excretion of urinary nitrogen per unit increase in ADN, and at the same intake of ADN (143 mg/kg live weight/day), they had the higher nitrogen balance: 58v.48 mg/kg live weight/day. Dietary metabolizable energy content did not affect the utilization of digested nitrogen.Estimates of metabolic faecal nitrogen and endogenous urinary nitrogen excretions and of maintenance requirements for digested nitrogen were similar to those of tropical large ruminants reported by other workers. On low-quality (0·8% N) or medium-quality (1·6% N) diets, it was calculated that buffaloes would have nitrogen balances.

The influence of physiological state and dietary nitrogen supply on digestion in the dairy cow.

1990 ◽  
Vol 68 (11) ◽  
pp. 3853 ◽  
Author(s):  
M Doreau ◽  
A Delacroix ◽  
J P Jouany ◽  
C Durier ◽  
B Rémond
Keyword(s):  
Dairy Cow ◽  
Physiological State ◽  
Nitrogen Supply ◽  
Dietary Nitrogen

Digestion and Nitrogen Metabolism in the Koala, Phascolarctos Cinereus.

1976 ◽  
Vol 24 (2) ◽  
pp. 201 ◽  
Author(s):  
CJF Harrop ◽  
R Degabriele
Keyword(s):  
Digestive Tract ◽  
Nitrogen Balance ◽  
Dry Matter ◽  
Apparent Digestibility ◽  
Digestive Efficiency ◽  
Seasonal Differences ◽  
Phascolarctos Cinereus ◽  
Dietary Nitrogen ◽  
Herbivorous Mammals

The dimensions of different regions of the digestive tract and digestive efficiency were determined in koalas maintained on leaves from the grey gum, Eucalyptus punctata, in summer and winter trials. Intakes of wet and dry matter, and apparent digestibility of dry matter, compared favourably with values reported for various other herbivorous mammals. Seasonal differences were marginal. A low but positive nitrogen balance was generally maintained in both seasons, although the apparent digestibility of nitrogen was lower in winter. This was reflected in the values for dietary and apparent digestible nitrogen intakes required for the maintenance of similar levels of nitrogen equilibrium in summer and winter. Mean nitrogen balances in summer and winter were not significantly different at 0.040 and 0.034 g/kg W*0.75 per day respectively. Daily dietary nitrogen intakes were significantly different, however, at 0.426 and 0.493 g/kg W*0.75 in summer and winter respectively, while the apparent digestible nitrogen intakes were not significantly different at 0.180 and 0.127 g/kg W*0.75 per day respectively. This is discussed in relation to the quality of the food offered. It is concluded that the digestive tract of the koala, presumably aided by the relatively large caecum, is well suited to the fibrous dietary matter on which the animal feeds.

The effects of urea supplements on the utilization of straw plus molasses diets by sheep

1963 ◽  
Vol 14 (1) ◽  
pp. 70 ◽  
Author(s):  
JB Coombe ◽  
DE Tribe
Keyword(s):  
Food Intake ◽  
Nitrogen Balance ◽  
The Body ◽  
Intake Rate ◽  
Crude Fibre ◽  
Cellulose Digestion ◽  
Dietary Nitrogen ◽  
Ad Libitum ◽  
Voluntary Intake ◽  
Food Intake Rate

Three experiments with sheep were carried out to investigate the effect of urea, added to a diet of straw plus molasses, on roughage intake and digestion, and on the nitrogen status of the animal. Urea, added to straw and molasses at the level of 3% of the amount of straw, increased the ad libitum food intake, rate of cellulose (cotton thread) digestion in the rumen, and rate of passage of food through the gut. When different amounts of urea were fed, the highest levels of intake, rate of cellulose digestion, and rate of passage occurred with 8–16 g urea per sheep per day. Increasing the amount of urea fed to 32 g per day caused significant decreases in rate of passage and intake, within diets containing urea. These were not accompanied by significant changes in rate of cellulose digestion in the rumen. With diets of straw and molasses, with and without urea, crude fibre digestibility was positively correlated with the rate of cellulose digestion in the rumen. Voluntary intake of these diets was positively correlated with rate of passage. When the effect of rate of passage was eliminated, voluntary intake was not significantly correlated with the rate of cellulose digestion in the rumen. Under the feeding conditions used in these experiments, once sufficient urea had been added to the diet to bring the animal into a small, positive nitrogen balance, additional dietary nitrogen supplied as urea was practically all excreted in the urine. It is concluded that, under these feeding conditions, the primary function of a urea supplement is to enable an animal to maintain nitrogen equilibrium rather than store significant amounts of nitrogen in the body.

scholarly journals Elevated CO2 concentrations alter nitrogen metabolism and accelerate senescence in sunflower (Helianthus annuus L.) plants  

2013 ◽  
Vol 59 (No. 7) ◽  
pp. 303-308 ◽  
Author(s):  
L. De la Mata ◽  
P. De la Haba ◽  
Alamillo JM ◽  
M. Pineda ◽  
E. Agüera
Keyword(s):  
Nitrate Reductase ◽  
Helianthus Annuus ◽  
Nitrogen Metabolism ◽  
Leaf Development ◽  
Nitrogen Assimilation ◽  
Nitrogen Availability ◽  
Leaf Ontogeny ◽  
Transcript Levels ◽  
Helianthus Annuus L ◽  
Accelerate Senescence

Elevated CO<sub>2</sub> concentrations were found to cause early senescence during leaf development in sunflower (Helianthus annuus L.) plants, probably by reducing nitrogen availability since key enzymes of nitrogen metabolism, including nitrate reductase (NR); glutamine synthetase (GS) and glutamate dehydrogenase (GDH), were affected. Elevated CO<sub>2</sub> concentrations significantly decreased the activity of nitrogen assimilation enzymes (NR and GS) and increased GDH deaminating activities. Moreover, they substantially rose the transcript levels of GS1 while lowering those of GS2. Increased atmospheric CO<sub>2</sub> concentrations doubled the CO<sub>2</sub> fixation and increased transpiration rates, although these parameters decreased during leaf ontogeny. It can be concluded that elevated atmospheric CO<sub>2</sub> concentrations alter enzymes involved in nitrogen metabolism at the transcriptional and post-transcriptional levels, thereby boosting mobilization of nitrogen in leaves and triggering early senescence in sunflower plants.

Sign in / Sign up

Export Citation Format

Share Document