The phosphorus requirement of lettuce: II. A dynamic model of phosphorus uptake and growth

1973 ◽  
Vol 80 (3) ◽  
pp. 353-361 ◽  
Author(s):  
M. A. Scaife ◽  
R. Smith
Keyword(s):  
Dynamic Model ◽  
Phosphorus Uptake ◽  
Normal Growth ◽  
Soil Mass ◽  
Relative Growth ◽  
P Content ◽  
Phosphorus Requirement ◽  
Low Levels ◽  
Parameter Values ◽  
P Supply

SummaryA dynamic model is presented in which the problem of predicting P response is broken down into various components, such as:(a) Weight and P content of emerging seedling.(b) Normal growth curve of the fully nourished plant.(c) A ‘deficiency-tolerance’ factor relating depression of relative growth rate to plant P concentration.(d) An ‘affinity’ term relating sink concentration to P status of plant.(e) A perirhizal resistance term for diffusive transport to roots.(f) Capacity and intensity of P supply from the soil. Mass flow supply via the transpiration stream is also included.By changing parameter values one may attempt to simulate the effect of any of these factors on the shape of the P response curve and any other part of the system throughout crop life. At present the model over-estimates growth at low levels of P supply, but predicted plant P concentrations agree reasonably well with observed data.

Screening cereals for genotypic variation in efficiency of phosphorus uptake and utilisation

2002 ◽  
Vol 53 (3) ◽  
pp. 295 ◽  
Author(s):  
L. D. Osborne ◽  
Z. Rengel
Keyword(s):  
Dry Matter ◽  
Shoot Growth ◽  
Genotypic Variation ◽  
Phosphorus Uptake ◽  
Dry Weight ◽  
P Efficiency ◽  
P Content ◽  
Shoot Growth Rate ◽  
Utilisation Efficiency ◽  
P Supply

One hundred and six Australian cereal genotypes, including wheat, triticale, and rye, were screened for their ability to take up and utilise soluble phosphorus at different rates of P supply. Plants were screened in outdoor tanks irrigated at regular intervals with nutrient solution amended with 3 rates of P. Genotypes were ranked according to the following 3 criteria: shoot growth at deficient P supply, the relative shoot growth rate (dry weight at deficient P/dry weight at sufficient P), and phosphorus utilisation efficiency (amount of dry matter produced per unit of P accumulated in shoots corrected for seed P content). Considerable genotypic variation in growth and P utilisation efficiency was found in the cereal germplasm. Rye and triticale were generally more efficient in taking up and utilising P than wheat at low rates of P supply. Wheat genotypes Egret and Durati showed relatively high, and genotype Cadoux relatively low, P efficiency.

scholarly journals Optimization of Different Factors for Initiation of Somatic Embryogenesis in Suspension Cultures in Sandalwood (Santalum album L.)

Horticulturae ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 118
Author(s):  
Manoj Kumar Tripathi ◽  
Niraj Tripathi ◽  
Sushma Tiwari ◽  
Gyanendra Tiwari ◽  
Nishi Mishra ◽  
...  
Keyword(s):  
Cell Suspension ◽  
Nutrient Medium ◽  
Normal Growth ◽  
Cell Suspension Cultures ◽  
Suspension Cultures ◽  
Embryonic Axis ◽  
Santalum Album ◽  
Relative Growth ◽  
Santalum Album L ◽  
Embryogenic Tissues

Santalum album (L.) is a prized tropical tree species of high therapeutic and industrial importance. The wood of these naturally grown plants is extensively harvested to acquire therapeutically important metabolite santalol and be used for additional functions such as in wood statuette industries. Due to high demand, it is crucial to maintain a sufficient plant population. An easy protocol for establishing cell suspension culture initiated from the loose embryogenic callus mass of sandalwood was realized by shifting 6–8-week-old morphogenic calli acquired from the mature embryonic axis and cotyledon explant cultures in fluid media. The asynchronous embryogenic cultures were sloughed with clumps of flourishing cell clumps and embryos of various progressive phases along with diffident non-embryogenic tissues. The frequency of embryo proliferation was evidenced to determinethe expansion pace of embryogenic masses under diverse conditions. The intonation of initiation and creation of cell suspension was under the directive of the influence of exogenous plant growth regulators amended in the nutrient medium at different concentrations and combinations. Maximum relative growth rate (386%) and clumps/embryoids in elevated integers (321.44) were accomplished on MS nutrient medium fortified with 2.0 mg L−1 2,4-D in association with 0.5 mg L−1 BA and 30.0 g L−1 sucrose raised from mature embryonic axis-derived calli. Plantlet regeneration in higher frequency (84.43%) was evidenced on MS medium amended with 1.0 mg L−1 each of TDZ and GA3 in conjunction with 0.5 mg L−1 NAA and 20.0 g L−1 sucrose. Mature embryonic axis-derived calli were found to be constantly better than mature cotyledon-derived calli for raising profitable and reproducible cell suspension cultures. Regenerants displayed normal growth and morphology and were founded successfully in the external environment after hardening.

scholarly journals Phosphorus fertilization and growth of buffel grass (Cenchrus ciliares L.) cultivars

2015 ◽  
Vol 19 (1) ◽  
pp. 34-38
Author(s):  
Vanderlise Giongo ◽  
Alessandra M. Salviano ◽  
Betina R. C. dos Santos ◽  
Emylly F. Leal
Keyword(s):  
Critical Level ◽  
Dry Mass ◽  
Phosphorus Fertilization ◽  
Critical Levels ◽  
Buffel Grass ◽  
P Accumulation ◽  
P Content ◽  
Phosphorus Requirement ◽  
Set Up

Phosphorus (P) plays an important role in the growth of root system as well as the tillering grass, being fundamental to increase the productivity of these species. The aim of this study was to evaluate the development of buffel grass cultivars and establish critical values of P in plant and soil. The experimental set up was a 4 x 5 factorial scheme (four Cenchrus ciliaris cvs.: Biloela, Aridus, CPATSA 7754 and Pusa Giant, and five doses of P2O5 - 0, 30, 60, 90 and 120 kg ha-1) with four replications. After 90 days of cultivation, dry mass of shoot (DMS) and root (DMR) production and the P accumulation (Pacc) were determined. Soil samples to determine the P content and determination of the critical level (CriLev) were also collected. The cv. Biloela presented lower DMR and DMS production compared to the other cultivars. The cultivares Biloela, Pusa Giant and Aridus showed different critical levels of P in soil and plant, obtained in the greenhouse showing that they have different requirement of this nutrient for their growth. The cultivar CPATSA 7754 showed higher phosphorus requirement and did not permit to establish critical levels with doses used in the present study.

scholarly journals Estimating the importance of maize root hairs in low phosphorus conditions and under drought

2019 ◽  
Vol 124 (6) ◽  
pp. 961-968 ◽  
Author(s):  
Florian Klamer ◽  
Florian Vogel ◽  
Xuelian Li ◽  
Hinrich Bremer ◽  
Günter Neumann ◽  
...  
Keyword(s):  
Root Hairs ◽  
Specific Root Length ◽  
P Uptake ◽  
Alkaline Soil ◽  
Secondary Effects ◽  
Short Root ◽  
P Deficiency ◽  
P Content ◽  
Low Phosphorus ◽  
P Supply

Abstract Background and Aims Root hairs are single-cell extensions of the epidermis that face into the soil and increase the root–soil contact surface. Root hairs enlarge the rhizosphere radially and are very important for taking up water and sparingly soluble nutrients, such as the poorly soil-mobile phosphate. In order to quantify the importance of root hairs for maize, a mutant and the corresponding wild type were compared. Methods The rth2 maize mutant with very short root hairs was assayed for growth and phosphorus (P) acquisition in a slightly alkaline soil with low P and limited water supply in the absence of mycorrhization and with ample P supply. Key Results Root and shoot growth was additively impaired under P deficiency and drought. Internal P concentrations declined with reduced water and P supply, whereas micronutrients (iron, zinc) were little affected. The very short root hairs in rth2 did not affect internal P concentrations, but the P content of juvenile plants was halved under combined stress. The rth2 plants had more fine roots and increased specific root length, but P mobilization traits (root organic carbon and phosphatase exudation) differed little. Conclusions The results confirm the importance of root hairs for maize P uptake and content, but not for internal P concentrations. Furthermore, the performance of root hair mutants may be biased by secondary effects, such as altered root growth.

scholarly journals Phosphorus requirement and partitioning in oat cultivars

2019 ◽  
Vol 49 (2) ◽  
Author(s):  
Jonas Manica ◽  
Pedro Alexandre Varella Escosteguy
Keyword(s):  
Avena Sativa ◽  
Cover Crop ◽  
Dry Matter ◽  
Phosphorus Content ◽  
Nutrient Requirements ◽  
Physiological Maturity ◽  
P Content ◽  
Phosphorus Requirement ◽  
Oat Cultivars ◽  
Dry Matter Weight

ABSTRACT: Maintenance fertilization changes with nutrient requirements and partitioning, but these are not well known for oat cultivars. The aim of this study was to evaluate whether phosphorus (P) requirements and partitioning vary among cultivars of oat (Avena sativa L.). The UPFA ‘Ouro’, UPFPS ‘Farroupilha’, IPR ‘Afrodite’, URS ‘FAPA Slava’, ‘Barbarasul’, ‘FAEM 007’, URS ‘Taura’, and ‘URS 21’ were cultivated in a Latosol with high P content in a greenhouse in 2015. Plants were sampled at physiological maturity and divided into roots, stem, leaves, and grain tissues. Phosphorus content and the dry matter weight of these parts were evaluated and the uptake amount and partitioning of P were estimated. The values of these variables differed across cultivars, except the P content in the grain (‘average’, 4.0g P kg-1). ‘Afrodite’ and ‘FAPA Slava’ have lower requirements and partitioning of P in the grain, but these did not vary among the other cultivars. Requirements and partitioning of P in stem and leaves increased in the following order: ‘Ouro’ and ‘Farroupilha’<‘Taura’ and ‘FAPA Slava’<‘URS 21’<‘Afrodite’, ‘Barbarasul’ and ‘FAEM 007’. Requirement and partitioning of P in roots, stem, leaves, and grain differs across cultivars, which indicates that this factor, besides how the oat is used (such as for grain, pasture, silage, cover crop), can be used to improve maintenance fertilization.

Phosphorus uptake and partitioning in two durum wheat cultivars with contrasting biomass allocation as affected by different P supply during grain filling

2020 ◽  
Vol 449 (1-2) ◽  
pp. 179-192 ◽  
Author(s):  
Mohamed El Mazlouzi ◽  
Christian Morel ◽  
Thierry Robert ◽  
Bofang Yan ◽  
Alain Mollier
Keyword(s):  
Durum Wheat ◽  
Biomass Allocation ◽  
Phosphorus Uptake ◽  
Grain Filling ◽  
Wheat Cultivars ◽  
P Supply

The relationship of Zonocerus variegatus (L.) (Acridoidea: Pyrgomorphidae) with cassava (Manihot esculenta)

1977 ◽  
Vol 67 (3) ◽  
pp. 391-404 ◽  
Author(s):  
E. A. Bernays ◽  
R. F. Chapman ◽  
E. M. Leather ◽  
A. R. McCaffery ◽  
W. W. D. Modder
Keyword(s):  
Hydrogen Cyanide ◽  
Manihot Esculenta ◽  
Normal Growth ◽  
The Other ◽  
Zonocerus Variegatus ◽  
Laboratory Studies ◽  
Low Levels ◽  
Relationship Of ◽  
The Relationship ◽  
Ibadan Nigeria

AbstractField and laboratory studies at Ibadan, Nigeria, showed that the young nymphs of Zonocerus variegatus (L.) normally reject cassava after biting it and die if they are confined on growing leaves. Later instars will eat cassava, especially when deprived of food for some time, but the adults progressively lose weight when restricted to feeding on growing cassava. On cut cassava, on the other hand, extensive feeding occurs and normal growth is maintained. The change from unpalatability to acceptability occurs within about an hour of cutting and is apparently associated with wilting. Cassava produces latex, but this was not distasteful to Zonocerus. The readiness to feed on growing cassava was associated with low levels of hydrogen cyanide production by the leaves; wilted leaves still produced hydrogen cyanide, but at a lower rate than turgid, growing leaves. In the area around Ibadan, Zonocerus regularly defoliates cassava in the latter part of the dry season, probably because a shortage of attractive foods forces the insect to eat cassava.

scholarly journals Activation of CLN1 and CLN2 G1 cyclin gene expression by BCK2.

1995 ◽  
Vol 15 (4) ◽  
pp. 1835-1846 ◽  
Author(s):  
C J Di Como ◽  
H Chang ◽  
K T Arndt
Keyword(s):  
Growth Rate ◽  
Slow Growth ◽  
Protein A ◽  
Normal Growth ◽  
Slow Growth Rate ◽  
G1 Cyclin ◽  
Complementation Groups ◽  
Low Levels ◽  
Activation Pathways ◽  
Parallel Activation

The Saccharomyces cerevisiae CLN3 protein, a G1 cyclin, positively regulates the expression of CLN1 and CLN2, two additional G1 cyclins whose expression during late G1 is activated, in part, by the transcription factors SWI4 and SWI6. We isolated 12 complementation groups of mutants that require CLN3. The members of one of these complementation groups have mutations in the BCK2 gene. In a wild-type CLN3 genetic background, bck2 mutants have a normal growth rate but have a larger cell size, are more sensitive to alpha-factor, and have a modest defect in the accumulation of CLN1 and CLN2 RNA. In the absence of CLN3, bck2 mutations cause an extremely slow growth rate: the cells accumulate in late G1 with very low levels of CLN1 and CLN2 RNA. The slow growth rate and long G1 delay of bck2 cln3 mutants are cured by heterologous expression of CLN2. Moreover, overexpression of BCK2 induces very high levels of CLN1, CLN2, and HCS26 RNAs. The results suggest that BCK2 and CLN3 provide parallel activation pathways for the expression of CLN1 and CLN2 during late G1.

43. Normal Growth of Dairy Cattle

1932 ◽  
Vol 3 (3) ◽  
pp. 310-316 ◽  
Author(s):  
Stephen Bartlett ◽  
Joan Lyster Jameson
Keyword(s):  
Growth Rate ◽  
Dairy Cattle ◽  
Relative Growth Rate ◽  
Live Weight ◽  
Normal Growth ◽  
Body Depth ◽  
Relative Growth ◽  
Rate Method

1. Normal curves of growth for dairy Shorthorn cattle from birth to 5 years of age are presented. These include height at withers, length of body, depth of chest and live weight.2. The expression of growth by the “Relative growth rate” method is discussed and illustrated. The method is particularly suitable for expressing the growth of calves under 6 months of age.

Phosphorus Uptake and Utilization by Tree Seedlings

1977 ◽  
Vol 25 (6) ◽  
pp. 571 ◽  
Author(s):  
NJ Barrow
Keyword(s):  
Phosphorus Uptake ◽  
Three Dimensional ◽  
Root Hairs ◽  
Trifolium Subterraneum ◽  
Unit Weight ◽  
Tree Seedlings ◽  
Native Forest ◽  
Eucalyptus Marginata ◽  
Relative Growth ◽  
Plant Parts

Seedlings of five native forest species and of Pinus radiata D. Don were grown in pots in a forest soil at a range of levels of added phosphate for up to 20 weeks. At intervals of 3 weeks, roots were examined for root hairs and mycorrhizas and the weights of plant parts and their phosphorus contents were measured. Components of growth and response were calculated from three-dimensional surfaces which had level of phosphate and time as the independent variables. Except for Banksia grandis Willd., the species responded to phosphate but the time at which the response appeared was affected by seed reserves of phosphorus. Thus response appeared much earlier for the small-seeded Eucalyptus divevsicolor F. Muell. and Acacia pulchella R. Br. than for the large-seeded Eucalyptus calophylla R. Br. and Eucalyptus marginata Donn. ex Sm. The absence of a response by the banksia seemed to arise because of a large seed reserve of phosphorus, a low relative growth rate and a very low concentration of phosphorus in the leaves for maximum photosynthesis. The rates of uptake of phosphorus per unit weight of roots were generally low but increased at a time coincident with the development of mycorrhizas. Relative growth rates and the net assimilation rates were also low and reached maximum values at low concentrations of phosphorus in the leaf. The outcome was that the level of applied phosphate needed for good early growth did not differ greatly from that of Trifolium subterraneum L.

Sign in / Sign up

Export Citation Format

Share Document