Pre-flowering Growth Stages Research Articles

Root Foraging Capacity in Bambara Groundnut (Vigna Subterranea (L.) Verdc.) Core Parental Lines Depends on the Root System Architecture during the Pre-Flowering Stage.

Characterizing the morphological variability in root system architecture (RSA) during the sensitive pre-flowering growth stage is important for crop performance. To assess this variation, eight bambara groundnut single genotypes derived from landraces of contrasting geographic origin were selected for root system architecture and rooting distribution studies. Plants were grown in a polyvinyl chloride (PVC) column system under controlled water and nutrient availability in a rainout shelter. Days to 50% plant emergence was characterized during the first two weeks after sowing, while taproot length (TRL), root length (RL), root length density (RLD), branching number (BN), branching density (BD) and intensity (BI), surface area (SA), root volume (RV), root diameter (RDia), root dry weight (RDW), shoot dry weight (SDW), and shoot height (SH) were determined at the end of the experiment, i.e., 35 days after emergence. Genotypes S19-3 and DipC1 sourced from drier regions of sub-Saharan Africa generally had longer taproots and greater root length distribution in deeper (60 to 90 cm) soil depths. In contrast, bambara groundnut genotypes from wetter regions (i.e., Gresik, Lunt, and IITA-686) in Southeast Asia and West Africa exhibited relatively shallow and highly branched root growth closer to the soil surface. Genotypes at the pre-flowering growth stage showed differential root foraging patterns and branching habits with two extremes, i.e., deep-cheap rooting in the genotypes sourced from dry regions and a shallow-costly rooting system in genotypes adapted to higher rainfall areas with shallow soils. We propose specific bambara groundnut genotype as donors in root trait driven breeding programs to improve water capture and use efficiency.

Impact of Turnip yellows virus infection on seed yield of an open-pollinated and hybrid canola cultivar when inoculated at different growth stages

Turnip yellows virus (TuYV; family Luteoviridae, genus Polerovirus) is the most economically damaging virus infecting canola (Brassica napus) in the south-west Australian grainbelt. However, the impact of TuYV infection at different growth stages on canola seed yield has not been examined. This information is vital for implementing targeted management strategies. Four glasshouse experiments were conducted to examine seed yield losses incurred by an open-pollinated (ATR Bonito) and hybrid (Hyola® 404RR) canola cultivar when aphid-inoculated with TuYV at GS12 (two leaves unfolded), GS17 (seven leaves unfolded), GS30 (beginning of stem elongation) and GS65 (full flowering). When inoculated at GS12 and GS17, cv. Bonito plants incurred 30 % and 36 % seed yield losses, respectively, compared to healthy plants. Similarly, cv. 404RR incurred 41 % and 26 % seed yield losses at GS12 and GS17, respectively. However, when inoculated at GS30, whilst cv. Bonito plants incurred a 26 % seed yield loss, cv. 404RR incurred no significant loss. Neither cultivar incurred seed yield losses from inoculation at GS65. Additional information was collected from these experiments to improve sampling protocols to enhance TuYV detection, with a molecular and serological technique. When canola plants were at pre-flowering growth stages, TuYV was reliably detected 7–14 days after inoculation (DAI) in the youngest leaf. Once flowering had begun, TuYV was consistently detected 7–14 DAI in petals and flower buds. In contrast, regardless of growth stage, testing the oldest leaf regularly resulted in delayed detection or false negatives. Information generated in this study helps to quantify the value of management strategies targeted at preventing TuYV spread in pre-flowering canola crops and ultimately increase the efficiency of resource use.

Chitosan application in the induction of water deficit tolerance in maize plants

The present research seeks to elucidate the feasibility of chitosan (CHT) in the induction of water deficit tolerance in different maize hybrids, contrasting tolerance to water restriction, tolerance and sensitivity. The maize plants were subjected to water deficit and foliar application of different chitosan doses (60, 100, 140, and 180 mg L-1) at the pre-flowering growth stage and evaluated during the stress period of fifteen days. To understand the induction behaviour of the tolerance to water restriction, biophysical parameters, such as water potential, relative water content and chlorophyll content, gas exchange, and biochemical assays, were quantified based on the activity of SOD, CAT, APX, and PAL antioxidant enzymes, lipid peroxidation activity and hydrogen peroxide content. Among the treatments, maize plants subjected to chitosan foliar application at a dose of 140 mg L-1 presented similar behavioural responses to plants under favourable irrigation conditions. Such positive responses are related to the high degree of activity of antioxidant enzymes, gas exchange and low levels of lipid peroxidation and hydrogen peroxide. The results support the potential use of CHT to increase tolerance to water stress.

Spatial distribution and seasonal variation of Limicolaria spp. infesting banana plantations in South West, Cameroon

This study was carried out as a prelude to elucidate a management plan that could limit residues in fruits and the environment without compromising quality. In order to meet our objectives, snails were randomly sampled from banana growth stages, different plant parts, residues, polythene bag-covered and uncovered banana bunches, and at different distances from the field edges. To assess seasonality of snail infestations, snails were sampled from the pre-flowering growth stage (January to September, 2012). The egg-laying and aestivating behaviours of snails were assessed by counting them from residues, weeds and soil. We recorded a higher number of snails on growth stages and plant parts in the rainy season compared to the dry season. The number of snails were significantly higher in the pre-flowering growth stages in the wet season (72.1 snails/plant) compared to those from the same stage in the dry season (0.88 snails/plant) (p=0.05). Although the highest number of snails were recorded on leaves in both seasons compared to other plants parts, the numbers were significantly higher on leaves during the rainy season compared to those in the dry season (p=0.05). Residues were the most preferred egg-laying and aestivating sites for snails while leaves on the ground haboured the highest number of snails in both seasons. We therefore concluded that focus on monitoring and management of the snails should be intensified during the rainy season with special attention on pre-flowered plants, uncovered bunches, and residues.

Metabolite profiling characterises chemotypes of Musa diploids and triploids at juvenile and pre-flowering growth stages

Bananas (Musa spp.) are consumed worldwide as dessert and cooking types. Edible banana varieties are for the most part seedless and sterile and therefore vegetatively propagated. This confers difficulties for breeding approaches against pressing biotic and abiotic threats and for the nutritional enhancement of banana pulp. A panel of banana accessions, representative of the diversity of wild and cultivated bananas, was analysed to assess the range of chemotypes available globally. The focus of this assessment was banana leaves at two growth stages (juvenile and pre-flowering), to see when during the plant growth metabolic differences can be established. The metabolic data corresponded to genomic trends reported in previous studies and demonstrated a link between metabolites/pathways and the genomes of M. acuminata and M. balbisiana. Furthermore, the vigour and resistance traits of M. balbisiana was connected to the phenolic composition and showed differences with the number of B genes in the hybrid accessions. Differences in the juvenile and pre-flowering data led to low correlation between the growth stages for prediction purposes.

First report of the bordered straw, Heliothis peltigera, οn sunflower in Greece

In June 2015, infestations of sunflower crops by the bordered straw Heliothis peltigera (Lepidoptera: Noctuidae) were recorded in rural areas of the Regional Unit of Drama, N. Greece. Larval feeding-damage symptoms were observed on leaves and buds of sunflower plants, mostly at pre-flowering growth stages. Infestations were recorded in approximately 80% of the inspected sunflower fields, the infestation levels, however, were low (<5%) apparently resulting in no economic damage. The presence of H. peltigera has been reported in Southern and Central Europe, Canada, the Middle East and Africa, infesting several hosts. Infestations of sunflower crops have been reported in India, Pakistan and Sudan. To our knowledge, this is the first report of H. peltigera infestations on sunflower crops in Greece and possibly in Europe.

IMPORTÂNCIA DO PERÍODO DE PRÉ-FLORAÇÃO NA PRODUTIVIDADE DO FEIJOEIRO

The objective of the present study was to determine the importance of the pre-flowering growth stage for common bean yield. In two assays, the common bean BRS-Pérola, BRS-Valente and Jalo Precoce cultivars were sown at five different dates, from April to August, in 2001 and 2002, at Embrapa Arroz e Feijão, in Santo Antônio de Goiás, Goiás State, Brazil. The experiments were carried out under conventional tillage, in a randomized split-plot block design, with four repetitions. Physiological parameters related to common bean plant growth, development and yield were correlated with temperatures and solar radiation incidence, during the pre-flowering plant growth period. Increases of minimum temperature, solar radiation, and N absorption rate, and decrease in N efficiency use, up to the third trifoliolate leaf stage, were correlated with yield reduction. The phenological period between emergence and third trifoliolate leaf is the most important one for common bean yield determination, when compared with the total pre-flowering period. KEY-WORDS: Phaseolus vulgaris; common bean development; temperature; solar radiation.

Importância do período de pré-floração na produtividade do feijoeiro

Objetivou-se verificar a importância do período da emergência à pré-floração, na produtividade do feijoeiro. Em dois ensaios, as cultivares BRS-Pérola, BRS-Valente e Jalo Precoce foram semeadas em cinco épocas, entre abril e agosto de 2001 e 2002, em área experimental da Embrapa Arroz e Feijão, em Santo Antônio de Goiás, GO, próxima a uma estação meteorológica. Os ensaios foram instalados em sistema convencional de preparo de solo, em delineamento experimental de blocos ao acaso, com parcelas subdivididas e quatro repetições. Características fisiológicas relacionadas a crescimento, desenvolvimento e produtividade foram correlacionadas com temperaturas e radiação solar incidentes no período. Aumentos na temperatura mínima, radiação solar e na taxa de absorção de N e diminuição na eficiência do uso de N, até o terceiro trifólio, foram correlacionados com redução na produtividade. Na fase de pré-floração, o subperíodo entre a emergência e o terceiro trifólio é o mais importante para a determinação do rendimento de grãos do feijoeiro.

Marcha de absorção do nitrogênio do solo, do fertilizante e da fixação simbiótica em feijão-caupi (Vigna unguiculata (L.) walp.) e feijão-comum (Phaseolus vulgaris L.) determinada com uso de 15N

O feijão-comum e o feijão-caupi estão entre as principais fontes de proteína vegetal para grande parte da população mundial, sobretudo aquela de baixa renda, e o N é o principal constituinte de proteínas. Os objetivos deste trabalho foram de avaliar, por meio da técnica isotópica e tendo como plantas-controle arroz e soja não nodulante, as contribuições relativas das fontes de N (N2-fixação simbiótica, N-solo e N-fertilizante) no desenvolvimento do feijão-comum e caupi ao longo do ciclo e comparar o método isotópico (MI) com o método da diferença (MD) para avaliação da fixação simbiótica de N2. A pesquisa foi realizada em casa de vegetação no Centro de Energia Nuclear na Agricultura - CENA/USP, utilizando-se vasos com 5 kg de terra de um Latossolo Vermelho-Amarelo distrófico. O delineamento experimental foi o de blocos casualizados com 16 tratamentos e três repetições. Os tratamentos (fatorial 8 x 2) compreenderam oito épocas de coleta: 17, 24, 31, 38, 47, 58, 68 e 78 dias após a semeadura (DAS) e duas culturas: feijão-comum e feijão-caupi. Utilizou-se uma dose de 10 mg kg-1 de N no solo, na forma de ureia, enriquecida com 10 % de átomos de 15N em excesso. A fixação simbiótica forneceu a maior parte do N acumulado nas plantas de feijão e caupi, seguida, em ordem decrescente, pelo solo e fertilizante. A maior taxa de fixação simbiótica de N ocorreu a partir da fase de prefloração do feijão e do caupi. Após a fase inicial (24 DAS), o arroz e a soja não nodulante tornaram-se adequadas plantas-controle da fixação simbiótica de N2. Houve boa concordância entre o MI e o MD, exceto nos estádios iniciais das culturas.

Effect of light and density on yellow starthistle (Centaurea solstitialis) root growth and soil moisture use

Yellow starthistle root growth was measured under field conditions using a minirhizotron camera system. Roots grew 1.0 to 1.3 cm d−1 and quickly reached the bottom of the 100-cm tube. When plants were grown under 80 and 92% shading, roots grew 45 and 64% slower, respectively, than when plants were grown unshaded. Using a neutron probe, we evaluated the effect of yellow starthistle density on soil moisture depletion to 180 cm in the soil profile. At the end of the growing season, we also measured aboveground biomass and seedhead production. Total plant dry weight and seedhead number at the lowest density (0.6 plants m−2) were 43 and 97% of the maximum values, respectively, suggesting that yellow starthistle is capable of reaching near-maximum yield at low densities. Moisture depletion was density dependent, and plants in low-density plots used more soil moisture from deep in the profile than from shallow soil (30 cm) early in the season. In contrast, yellow starthistle densities > 90 plants m−2 rapidly depleted moisture from all depths in the soil profile by preflowering growth stages. High yellow starthistle density expands the moisture depletion zone and leads to increased shallow moisture depletion. In high-density plots, soil moisture did not recharge, compared with bare-ground plots, after subnormal winter and spring precipitation. These results illustrate the importance of reducing yellow starthistle densities in grassland restoration efforts, where shallow soil moisture is critical to the establishment of seeded perennial grasses or annual forbs and where moderate to deep soil moisture is essential for the establishment and survival of transplanted shrubs and trees.

Effects of elevated CO 2 concentration on the polyamine levels of field-grown soybean at three O 3 regimes

Effects of increased ozone (O 3) and carbon dioxide (CO 2) on polyamine levels were determined in soybean ( Glycine max L. Merr. cv. Clark) grown in open-top field chambers. The chamber treatments consisted of three O 3 regimes equal to charcoal filtered (CF), non-filtered (NF), and non-filtered plus 40 nl litre −1 O 3 and CO 2 treatments equal to 350, 400 and 500 μl litre −1 for a total of nine treatments. Leaf samples were taken at three different times during the growing season. Examination of growth and physiological characteristics, such as photosynthesis, stomatal resistance, and shoot weight, revealed that increasing CO 2 ameliorated the deleterious effects of increased O 3. Results from the initial harvest, at the pre-flowering growth stage (23 days of treatment), showed that increasing O 3 at ambient CO 2 caused increases in putrescine (Put) and spermidine (Spd) of up to six-fold. These effects were lessened with increased CO 2. Elevated CO 2 increased polyamines in plants treated with CF air, but had no effect in the presence of ambient or enhanced O 3 levels. Leaves harvested during peak flowering (37 days of treatment) showed O 3-induced increases in Put and Spd at ambient CO 2 concentrations. However, increased CO 2 levels inhibited this response by blocking the O 3-induced polyamine increase. Leaves harvested during the pod fill stage (57 days of treatment) showed no significant O 3 or CO 2 effects on polyamine levels. Our results demonstrate that current ambient O 3 levels induce the accumulation of Put and Spd early in the growing season and that further increases in O 3 could result in even greater polyamine increases. These results are consistent with a possible antiozonant function for polyamines. The ability of increased CO 2 to protect soybeans from O 3 damage, however, does not appear to involve polyamine accumulation.

Control of Russian Thistle (Salsola iberica) with Chlorsulfuron in a Wheat (Triticum aestivum) Summer-Fallow Rotation

Greenhouse and field experiments were conducted to evaluate the efficacy of chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} on Russian thistle (Salsola ibericaSennen and Pau # SASKR) in a spring wheat (Triticum aestivumL.) summer-fallow rotation. In the greenhouse, when chlorsulfuron was applied to Russian thistle at three stages of growth, shoot dry weight was reduced similarly with either 4.4 g ai/ha plus surfactant or 140 g ai/ha plus surfactant. In the field, postharvest control (1981) of Russian thistle with 17.5 to 140 g/ha of chlorsulfuron ranged from 35 to 60% without surfactant and from 76 to 93% with surfactant. During the summer-fallow year (1982), Russian thistle treated in the preflowering stage of growth was not effectively controlled with 17.5 or 35 g/ha. In contrast, residual control from postharvest treatments 1 yr after application ranged from 90 to 100%. Chlorsulfuron applied in the crop (1983) controlled Russian thistle throughout the growing season. All treatments of chlorsulfuron applied in 1981, 1982, and 1983 increased wheat yield at least 75%.

Effect Of Inoculation With Native Phosphate Solubilizing Microorganisms On The Available Phosphorus Content In The Rhizosphere And Uptake Of Phosphorus By Rice Plants, Grown In An Indian Alluvial Soil

Summary Three efficient phosphate solubilizing microorganisms, isolated from an alluvial soil (Fluvaquent), ACB 6 — Bacillus firmus (B - 7651), ACS 6 - Streptomyces sp. and ACF 2 — Aspergillus Candidus , were used to inoculate in rock phosphate (BP), farmyard manure (FYM), FYM + KP, rice straw (RS), and RS + RP to study their effect on the available phosphorus content of the rhizosphere soils, uptake of phosphorus by and dry weight of rice ( Oryza sativa L., cv. IR-8) plants at early tillering and preflowering stages of growth in a pot culture experiment with the same soil. In an average, available phosphorus content of the rhizosphere soils of IR-8 rice increased significantly with the application of RS and with a combined inoculation of ACB 6 + ACS 6 + ACF 2 · So happened for the uptake of phosphorus by plants with FYM and with a combined inoculation of ACB 6 + ACS 6 and for dry weight of the plants with FYM and with a combined inoculation of ACS 6 + ACF 2 . Accumulation of available phosphorus in the rhizosphere, uptake of phosphorus by the plants and dry weight of the plants were found highest with the inoculation of ACB 6 with RS; ACB 6 + ACS 6 + ACF 2 with RS + RP and with ACB 6 + ACS 6 with RP, respectively, at early tillering stage and with the inoculation of ACB 6 + ACS 6 with RS; ACB 6 + ACS 6 with FYM; and ACF 2 with FYM + RP, respectively, at preflowering stage of growth. Thus a combined inoculation of the native phosphate solubilizing isolates, either two or three taken together coupled with the judicial application of FYM and RS in presence and absence of RP would be beneficial for the rice crop.

Yield Losses in Field Beans Following Foliar Damage by Ootheca bennigseni (Coleoptera: Chrysomelidae)

The effects of the foliar beetle, Ootheca bennigseni (Weise), infestation on seed yield of some cultivars of field beans ( Phaseolus vulgaris L.) were studied. In the absence of insecticide protection during pref lowering growth stage, cv. Selian Wonder and Masonga, suffered high yield losses and were considered susceptible to O. bennigseni. Cultivar T8 and Mexican 142 had comparatively lower damage ratings of 1.31 and 1.38, respectively, compared with 2.26 and 2.56 for ‘Selian Wonder’ and ‘Masonga’ on a 0 to 5 damage scale, and were considered resistant. Nonpreference and tolerance were the mechanisms of resistance in the resistant cultivars. Bean seed yield losses from 18 to 31% resulted from foliar damage by O. bennigseni. Although the yields in ‘T8’ and ‘Mexican 142’ were significantly higher than those in susceptible cultivars, there was an increase in the yield when these cultivars were sprayed with insecticides because of their resistance to O. bennigseni. These data suggest that for resistant cultivars, one or two sprays can appreciably reduce foliar damage by O. bennigseni and increase seed yields.

Yield Losses in Cowpea Following Leafhopper Damage1

Yield response of cowpea, Vigna unguiculata L. (Walp.), to infestation by a leafhopper Empoasca dolichi (Paoli) was studied in the field and greenhouse by using resistant and susceptible cultivars. Field studies indicated that in the absence of insecticidal protection during the preflowering growth stage, susceptible cultivars TVu 2045 and TVu 76 were severely damaged with a yield loss of more than 40%. Resistant cultivars TVu 1190E, TVu 662, TVu 3629, and TVu 4557 had a foliar damage rating of 3.0 and indicated no significant yield loss. In greenhouse studies, the susceptible cultivar TVu 76 was significantly reduced in plant height, pods per plant, and grain yield.

The effect of sulphur on the growth, sulphur and nitrogen concentrations, and critical sulphur concentrations of some tropical and temperate pasture legumes

Seven tropical and five temperate pasture legume species were grown in pots of three sulphur-deficient soils with varying additions of sulphate. Growth responses and the chemical composition of the plant tops were recorded, and from the latter, tentative critical concentrations of sulphur were established. These were compared with data from two field sites (six species only). Critical concentrations of sulphur in the tops of species sampled at the immediate pre-flowering stage of growth were: Macroptilium lathyroides 0.17%, Macroptilium atropurpureum 0.15%, Desmodium intortum 0.17%, Desmodium uncinatum 0.17%, Stylosanthes humilis 0.14%, Lotononis bainesii 0.15%, Glycine wightii 0.17%, Trifolium repens 0.18%, Trifolium semipilosum 0.17%, Medicago sativa 0.20%, Medicago truncatula 0.20% and Medicago denticulata 0.20%. Sulphate concentration and nitrogen/sulphur ratios were investigated as alternative diagnostic indices, but were not considered as suitable as total sulphur indices for the assessment of sulphur deficiency in legumes. Nitrogen concentrations in the plant tops were increased by sulphate supply, and excellent correlations were established between the nitrogen and sulphur concentrations in the plant tops.

Development, Survival, and Fecundity of the Cotton Fleahopper, Pseudatomoscelis seriatus (Reuter), on Several Host Plants 1

Mortality and developmental rates of the cotton fleahopper, Pseudatomoscelis seriatus (Reuter), were affected by the species and maturity of host plants. Survival was higher and development was faster on Croton sp. than on other hosts such as spotted beebalm, Monarda punctata L., cutleaf primrose, Oenothera laciniata Hill, and cotton, Gossypium hirsutum L. Also, survival and development rates were higher on flowering plants than on plants in a preflowering growth stage. Predictions of fleahopper development based on temperature data were affected by the host plant. Heat units required for total nymphal development varied from 98.2°C days on flowering croton to 163.2°C-days on preflowering cutleaf primrose.

The effect of phosphorus on the growth, chemical composition, and critical phosphorus percentages of some tropical pasture grasses

Nine tropical pasture grasses were grown in pots of a phosphate-deficient solodic soil with varying additions of phosphate. Growth responses and chemical composition of the plant tops were recorded, and from these, critical percentages of phosphorus were established. All species responded to phosphate addition. Under the conditions of this experiment Melinus minutiflora was the most responsive species and Pennisetum clandestinum the least responsive. Critical percentages of phosphorus in the tops of Melinus minutiflora, Cenchrus ciliaris, Paspalum dilatatum, Panicum maximum, Chloris gayana, Sorghum almum, Setaria anceps, Digitaria decumbens and Pennisetum clandestinum sampled at the immediate pre-flowering stage of growth were 0.18, 0.25, 0.25, 0.20, 0.22, 0.20, 0.21, 0.16, and 0.22% respectively of the dry matter. Phosphate applications decreased the concentration of plant potassium, had no significant effect on calcium, increased magnesium in most species, and in four species increased sodium. The increases in magnesium and sodium are considered to result in part from reduced potassium uptake and the plant's ability to preserve cation balance. Three species, C. gayana, P. maximum and D. decumbens, had relatively high concentrations of sodium (58, 46, and 46% of total cations respectively). In contrast S. anceps had a relatively high concentration of potassium (56 % of total cations) and low sodium (7%). Phosphate applications decreased the concentration of nitrogen, and had little effect on chloride.

The effect of potassium on the growth and chemical composition of some tropical and temperate pasture legumes. I. Growth and critical percentages of potassuim

Eight tropical and four temperate pasture legumes were grown in pots of a potassium-deficient soil, with varying additions of potassium chloride. Growth responses and chemical composition of the plant tops were recorded, and from these, critical percentages of potassium in the plant tops were established. All species responded in growth to potassium additions; however, there was practically no increase in plant potassium concentration over the low treatment range of potassium chloride. Medium to high rates of application increased plant potassium. Critical percentages of potassium in the tops of Phaseolus lathyroides, P. atropurpureus, Desmodium intortum, D. uncinatum, Stylosanthes humilis, Lotononis bainesii, Centrosema pubescens, Glycine javanica, Medicago sativa, M. truncatula, Trifolium repens, and T. fragiferum sampled at the immediate pre-flowering stage of growth were 0.75, 0.75, 0.80, 0.72, 0.60, 0.90?, 0.75, 0.80, 1.2, 1.0, 1.0, and 1.0% potassium respectively in the dry matter. In this work an absolute critical percentage has not been sought, but rather a working value for the rapid diagnosis of nutrient deficiency.

The effect of phosphorus on the growth and chemical composition of some tropical pasture legumes. I. Growth and critical percentages of phosphorus

Nine tropical and one temperate pasture legume species were grown in pots of soil with varying additions of phosphate. Growth responses and chemical conlposition of the plant tops were recorded, and from the latter, critical percentages of phosphorus were established. These were verified by using data from two soils in the pot culture investigation and a total of six field sites. Glycine javanica and Desmodium intortum were the most responsive species in pots, and Stylosanthes humilis and Lotononis bainesii were the least responsive species. The quantity of phosphorus per pot accumulated in the tops of the plants was greatest for Stylosanthes humilis and Lotononis bainesii at all treatment levels. Critical percentages of phosphorus in the tops of Phaseolus Iathyroides, Phaseolus atropurpureus, Stylosanthes humilis, Centrosema pubescens, Glycine javanica, Lotononis bainesii, Medicago sativa, Desmodium uncinatum, Desmodium intortum, and Vigna luteola sampled at the immediate pre-flowering stage of growth were 0.20, 0.24, 0.17, 0.16, 0.23, 0.17, 0.24, 0.23, 0.22, and 0.25% phosphorus respectively.