Phosphorus efficiency in pasture species. III. Correlations of dry matter accumulation with phosphorus pool sizes and their net transfer rate

1988 ◽  
Vol 39 (5) ◽  
pp. 827 ◽  
Author(s):  
RH Chisholm ◽  
GJ Blair
Keyword(s):  
White Clover ◽  
Dry Weight ◽  
Incorporation Rate ◽  
Species Selection ◽  
Phosphorus Efficiency ◽  
Dry Matter Accumulation ◽  
P Efficiency ◽  
Transfer Coefficients ◽  
P Pools ◽  
Soluble P

Results of an experiment over five solution P concentrations ( 1 , 2, 4, 8, 16 8M P) and five harvests were used in a response surface approach to determine the size and incorporation rates of major plant P pools in white clover (Trifolium repens cv. Ladino) and stylo (Stylosanthes hamata cv. Verano).At low P stylo had a greater total flux of P from the soluble P (inorganic P, ester P) pool to supply lipid and residue P (RNA, DNA, phosphoprotein) pools.At high P concentrations large soluble P pools in tops were associated with depressed dry weight accumulation in stylo compared to white clover. Possible reasons for this effect of soluble P, as related to photosynthetic rate, are discussed.Since both pool size and incorporation rate affected the efficiency of phosphorus use, the two measures were combined in a model of plant P use to assist in understanding reaction to high or low P. The model demonstrated the importance of maintenance of P supply to structural P pools, particulary phospholipids, at low P levels.Pool size and incorporation rate were combined as a transfer coefficient of P. RGR was best correlated with the transfer coefficients of structural (lipid, residue) pools in the roots rather than the tops. R2 values as high as 0.99 were obtained for relationships between structural P pools and dry weight. Strong correlations were also found when the data of both species were combined, including that the same factors were associated with RGR in different species. Selection for 'P efficiency' based on biochemical parameters is possible, but must take account of roots rather than simpler tops P concentrations.

Phosphorus efficiency in pasture species. I. Measures based on total dry weight and P content

1988 ◽  
Vol 39 (5) ◽  
pp. 807 ◽  
Author(s):  
RH Chisholm ◽  
GJ Blair
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
White Clover ◽  
Phosphorus Deficiency ◽  
Dry Weight ◽  
Phosphorus Efficiency ◽  
P Efficiency ◽  
Relative Growth ◽  
Internal Efficiency ◽  
Better Than

Two solution culture experiments were conducted to compare the efficiency of phosphorus use and indicies for measuring it in a tropical and a temperate pasture legume. The species chosen were Stylosanthes hamata cv. 'Verano' (Caribbean stylo) and Trifolium repens cv. 'Ladino' (white clover).The first experiment used two solution P concentrations (2, 16 8M) to investigate differences between species in the rate and extent of P uptake. The second experiment used five solution P concentrations (1, 2, 4, 8, 16 8M ) to evaluate differences between species in internal efficiency of P utilization.There was no difference between white clover and stylo in the capacity to remove P from the same solution P concentrations. However, in both species the extent of depletion of solutions by plants grown at high P was not as great as that plants grown at low P. The ranking of species in terms of their internal efficiency or relative growth rate changed with time and P concentrations.Growth of white clover was better than stylo where there was a moderate deficiency of phosphorus. Alternatively, growth of stylo was better than white clover where phosphorus deficiency was more severe. The relative growth rate of stylo at low (2 8M ) P was maintained above 8% per day after prolonged P stress, whilst in white clover at the same P concentration RGR fell to less than 2% per day.Internal P efficiency or the amount of dry matter accumulated per unit P accumulated per unit time showed that white clover was more P efficient than stylo in the early stages of growth.

scholarly journals   Effect of elevated CO2 and temperature on phosphorus efficiency of wheat grown in an Inceptisol of subtropical India

2012 ◽  
Vol 58 (No. 5) ◽  
pp. 230-235 ◽  
Author(s):  
Manoj-Kumar ◽  
A. Swarup ◽  
A.K. Patra ◽  
J.U. Chandrakala ◽  
K.M. Manjaiah
Keyword(s):  
Grain Yield ◽  
Dry Weight ◽  
P Uptake ◽  
Utilization Efficiency ◽  
Phosphorus Efficiency ◽  
Total Biomass ◽  
P Efficiency ◽  
Plant Parts ◽  
P Fertilizer ◽  
P Utilization

In a phytotron experiment, wheat was grown under two levels of atmospheric CO<sub>2</sub> [ambient (385 ppm) vs. elevated (650 ppm)], two levels of temperature (ambient vs. ambient +3&deg;C) superimposed with three levels of phosphorus (P) fertilization: 0, 100, and 200% of recommended dose. Various measures of P acquisition and utilization efficiency were estimated at crop maturity. In general, dry matter yields of all plant parts increased under elevated CO<sub>2</sub> (EC) and decreased under elevated temperature (ET); however, under concurrently elevated CO<sub>2</sub> and temperature (ECT), root (+36%) and leaf (+14.7%) dry weight increased while stem (&ndash;12.3%) and grain yield (&ndash;17.3%) decreased, leading to a non-significant effect on total biomass yield. Similarly, total P uptake increased under EC and decreased under ET, with an overall increase of 17.4% under ECT, signifying higher P requirements by plants grown thereunder. Although recovery efficiency of applied P fertilizer increased by 27%, any possible benefit of this increase was negated by the reduced physiological P efficiency (PPE) and P utilization efficiency (PUtE) under ECT. Overall, there was ~17% decline in P use efficiency (PUE) (i.e. grain yield/applied P) of wheat under ECT. &nbsp;

Phosphorus efficiency in pasture species. II. Differences in the utilization of P between major chemical fractions

1988 ◽  
Vol 39 (5) ◽  
pp. 817 ◽  
Author(s):  
RH Chisholm ◽  
GJ Blair
Keyword(s):  
Dry Weight ◽  
Biochemical Parameter ◽  
P Uptake ◽  
Solution Culture ◽  
Feedback Effect ◽  
Phosphorus Efficiency ◽  
Stylosanthes Hamata ◽  
P Concentration ◽  
Soluble P ◽  
Final Harvest

A solution culture experiment was conducted over a range of initial solution P concentrations (1-16 8M P) to investigate differences in P utilization of a tropical and temperate pasture legume. The species used were white clover (Trifolium repens cv. 'Ladino') and Caribbean stylo (Stylosanthes hamata cv. 'Verano'). Incorporation of solution 31P and a pulse of 32P into the soluble (inorganic, ester P), lipid and residue (phytin RNA, DNA, phosphoproteins) fractions of roots and tops was monitored over five harvests. At low P concentrations the major finding was that clover reduced its incorporation of 31P and 32P into root phospholipids at the final harvest. The reduction in P concentration in phospholipids coincided with reductions in relative growth rate of the whole plant by the final harvest, which were discussed in the first paper of this series.At high P concentrations, dry weight accumulation was related to the extent to which absorbed P was incorporated from the soluble to the lipid and residue fractions. While clover had higher dry weights and a greater incorporation capacity at high P.Correlation coefficients between dry weight and biochemical parameters showed that the best correlations between dry weight and any biochemical parameter was for the relationship between dry weight and residues P or lipid plus residue P content. A relationship between P uptake rate and root soluble P concentration indicated that root soluble P may have a feedback effect on P uptake. The negative feedback effect was greatest in stylo at high solution P concentration.

Dry-matter distribution and seasonal yield changes in five contrasting genotypes of white clover

1984 ◽  
Vol 102 (2) ◽  
pp. 333-340 ◽  
Author(s):  
R. Haycock
Keyword(s):  
White Clover ◽  
Field Trial ◽  
Dry Matter ◽  
Principal Component ◽  
Dry Weight ◽  
Dry Matter Accumulation ◽  
Matter Distribution ◽  
Dry Matter Distribution ◽  
Cyclical Pattern ◽  
Number Of Leaves

SummaryA field trial of five contrasting types of white clover grown in monoculture was established in August 1978. Measurements commenced in October and continued for 12 months during which time no additional treatments were applied.Seasonal trends of dry-matter accumulation and distribution were recorded and particular reference was made to the components of harvestable yields, which showed a strong seasonal trend. During the summer the density of growing points decreased in all types except D while the number of leaves per growing point and mean dry weight per leaf increased. The principal component of yield, mean dry weight per leaf, increased later than number of leaves per growing point. Stolons did not show the same cyclical pattern and produced an overall increase during the experiment. The five genotypes also showed large variation in the distribution of dry matter between leaves, flowers, stolons and roots.

Phosphorus efficiency in pasture species. V. A comparison of white clover accessions

1991 ◽  
Vol 42 (3) ◽  
pp. 531 ◽  
Author(s):  
DC Godwin ◽  
GJ Blair
Keyword(s):  
White Clover ◽  
New South ◽  
Soil Phosphorus ◽  
P Uptake ◽  
Phosphorus Efficiency ◽  
Shoot Biomass ◽  
P Efficiency ◽  
South Wales ◽  
Trifolium Repens L ◽  
Extractable Soil

Seed collections of 'naturalized' white clover (Trifolium repens L.) accessions, believed to have been derived from a Dutch 'wild white' clover introduced into the Northern Tablelands area of New South Wales were made. The collections were made from areas with low, high, and intermediate concentrations of extractable soil phosphorus. In a controlled environment pot experiment, the shoot and root growth and P uptake of each of these accessions was compared over a range of six P rates to three commercially available accessions-Ladino, Grasslands Huia, and Haifa and an accession from Algeria. Various methods of determining the efficiency of ultilization of P were examined. By all methods studied, Ladino generally was more efficient at utilizing applied P. Ladino produced a larger shoot biomass and greater length of root than other accessions, had a higher P uptake, and was more efficient in utilizing this P for the synthesis of biomass. The rankings of the clover accessions in terms of P efficiency changed according to the definition used. The study suggests that some scope exists for selection for P efficiency in clover accessions.

Phosphorus efficiency in pasture species. IV. Yield, efficiency parameters and partitioning of P in two white clover accessions under varying levels of P supply in solution culture

1990 ◽  
Vol 41 (6) ◽  
pp. 1071 ◽  
Author(s):  
GJ Blair ◽  
EJ Wilson
Keyword(s):  
White Clover ◽  
Phosphorus Uptake ◽  
Relative Yield ◽  
Nutrient Utilization ◽  
Phosphorus Efficiency ◽  
Yield Response ◽  
P Efficiency ◽  
Lower Efficiency ◽  
Seed Collection ◽  
P Supply

An experiment was conducted under controlled environment conditions in nutrient solution over four P levels (1,4, 8, 16 8mol P m-3) to evaluate the yield performance and P uptake of two accessions of white clover (Trifolium repens). The two accessions used were Naturalized, which was grown from a seed collection made from a low P soil on the Northern Tablelands of N.S.W., and cv. Ladino. Nutrient solutions were renewed when the P concentrations fell by a maximum of 10% and were pumped so that there was a flow rate of 4.4 L min-1 over the plant roots. The shoot and root fresh weight yield of Ladino was higher than Naturalized at all P levels. At 16 8mol P m-3 the shoot yield of Ladino was fourfold that of Naturalized; however, the relative yield response of Ladino between 1 and 16 8mol P m-3 was only 20% of the response of that in Naturalized. Phosphorus uptake was highest in Ladino at all P levels. The minimum shoot labile P concentrations recorded in this study were 1.1 and 2.5 8mol P g F.wt-1for Ladino and Naturalized respectively, indicating that Naturalized is capable of maintaining relatively high soluble tissue P levels under low P supply. The generally higher labile, lipid and residue P levels in new leaf, old leaf, stem and root in the Naturalized white clover accession indicate a lower efficiency of nutrient utilization in this collection compared to Ladino. In contrast to Ladino, Naturalized white clover may be able to control its P accumulation at high levels of supply, as toxic levels do not accumulate in old leaf. Ladino was the more efficient accession when P efficiency was defined as shoot yield per unit of P in solution. When P efficiency was defined as shoot or plant yield per unit of P absorbed or as the inverse of P concentration (utilization quotient), Ladino was the more efficient accession at 1 and 4 8mol P m-3, with only small differences between the accessions at 8 and 16 8mol P m-3. The results suggest that Naturalized may be adapted to low P supply through its low inherent growth rate which lowers its demand for exogenous P.

Phosphorus efficiency in pasture species. VI. A comparison of Italian ryegrass, phalaris, red clover and white clover over time

1991 ◽  
Vol 42 (3) ◽  
pp. 541 ◽  
Author(s):  
PD Kemp ◽  
GJ Blair
Keyword(s):  
White Clover ◽  
Red Clover ◽  
P Uptake ◽  
Italian Ryegrass ◽  
Phosphorus Efficiency ◽  
Shoot Biomass ◽  
Root Weight ◽  
P Efficiency ◽  
Over Time ◽  
Broad Scale

Two problems in comparative studies of the P efficiency of pasture species are the choice of measurement to define P efficiency and the basis of comparison to use. Therefore, the degree to which the level of P supply and plant age, or time of harvest, influence a variety of measures of P efficiency was examined in four temperate pasture species grown in a soil at a range of P levels in a glass house. The four species were Italian ryegrass, phalaris, red clover, and white clover. Italian ryegrass was the most P efficient and red clover the least P efficient species in terms of the broad scale measures of P effiency, shoot yield per unit of P applied and total P uptake over the first 40 days after sowing (DAS), and shoot P concentration at 68 DAS. Nevertheless, by 68 DAS the shoot fresh weight yield of the four species was similar at both the low (5 kgP ha-1) and the high (80 kg P ha-1) P rate. The superior shoot biomass production at lower P rates over 40 DAS of Italian ryegrass and phalaris compared with red and white clovers was largely the result of a greater root weight and P uptake per plant. Early root weight was determined by the relationship between seed weight and root relative growth rate (PGR), whereas P uptake per plant was influenced by root weight and plant P demand as measured by relative P uptake rate (RPR). The understanding of such relationships was shown to be essential to the effective interpretation of broad scale measures of P efficiency. The comparative broad scale P efficiences of the four species changed over time. When Italian ryegrass and phalaris were compared on an ontogenetic basis, number of leaves per plant, shoot yield and P uptake per plant were similar. The comparison of the P efficiency of species on both an ontogenetic and temporal basis is proposed.

Genetic variation for rate of establishment in caucasian clover

1998 ◽  
pp. 213-217
Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters
Keyword(s):  
Genetic Variation ◽  
Root Growth ◽  
Seedling Growth ◽  
White Clover ◽  
Seedling Emergence ◽  
Red Clover ◽  
Dry Weight ◽  
Cool Season ◽  
Trifolium Ambiguum ◽  
Root Dry Weight

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum

EFFECTS OF TEMPERATURE ON RATE AND DURATION OF KERNEL DRY MATTER ACCUMULATION OF MAIZE

1988 ◽  
Vol 68 (4) ◽  
pp. 935-940 ◽  
Author(s):  
M. TOLLENAAR ◽  
T. W. BRUULSEMA
Keyword(s):  
Growth Rate ◽  
Zea Mays ◽  
Dry Matter ◽  
Zea Mays L ◽  
Dry Weight ◽  
Controlled Environment ◽  
Dry Matter Accumulation ◽  
Linear Kernel ◽  
Effects Of Temperature ◽  
Kernel Growth

The response of rate and duration of kernel dry matter accumulation to temperatures in the range 10–25 °C was studied for two maize (Zea mays L.) hybrids grown under controlled-environment conditions. Kernel growth rates during the period of linear kernel growth increased linearly with temperature (b = 0.3 mg kernel−1 d−1 °C−1). Kernel dry weight at physiological maturity varied little among temperature treatments because the increase in kernel growth rate with increase in temperature was associated with a decline in the duration of kernel growth proportional to the increase in kernel growth rate.Key words: Zea mays L, period of linear kernel dry matter accumulation, controlled-environment conditions, kernel growth rate

Third generation progress in breeding white clover for resistance to root-knot nematode

1996 ◽  
Vol 6 ◽  
pp. 163-166
Author(s):  
J. Van den Bosch ◽  
C.F. Mercer
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Egg Production ◽  
Control Method ◽  
Dry Weight ◽  
Third Generation ◽  
Root Knot Nematode ◽  
Root Dry Weight ◽  
Wide Range ◽  
Meloidogyne Sp

Root-knot nematode (Meloidogyne sp.) reduces growth and nutrition of white clover (Trifolium repens L.) in New Zealand, and breeding resistant cultivars (with low galls per gram of root) is the preferred control method. Resistant and susceptible selections were bred from a wide range of white clover lines for three generations. In the third generation there were significant differences between seed lines from the selections for number of galls, root dry weight, visual growth score and galls/gram of root dry weight. Resistant selections had 43% of the susceptible selections' galls per gram, and 50% of the number of galls. Germplasm showing resistance to Meloidogyne spp. in the USA showed partial resistance to the local Meloidogyne sp. Two resistant and two susceptible genotypes were also compared for nematode egg production; resistant genotypes had a mean of 3,460 eggs/plant, compared to 25,030 for susceptible genotypes. Keywords: breeding, Meloidogyne sp., resistance, rootknot nematode, screening, selection, Trifolium repens, white clover

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