Phosphorus fractions in trifoliate leaves of white clover and lotus at various levels of phosphorus supply

Abstract

The concentrations of total P, inorganic (Pi), lipid, and ester P were measured in the youngest mature trifoliate leaves of white clover and lotus plants grown at various levels of P supply, In white clover, the Pi concentration rose as the P supply increased, even though there was no dry matter response by the shoots at the highest levels of P, In contrast, the shoot dry weight of lotus, which was generally higher than that of white clover, continued to increase over the whole range of P supply, and the Pi concentration remained unchanged, The concentration of lipid and ester P in both species increased only slightly with P supply, The concentration of total P declined markedly with trifoliate leaf age in lotus, The concentration of Pi, lipid P, and ester P also declined but less so, The P content and dry weight of basal leaflets of lotus leaves was about 25 % of that of the trifoliate leaves, White clover is typical of plants from fertile sites, Its growth responds markedly to increase in P supply, excess Pi being stored in vacuoles, Lotus can grow well at both high and low P supply, and P concentrations in the shoots are maintained at relatively low levels, This behaviour is in contrast to that of other plants adapted to low soil fertility,

Phosphorus fractions in relation to growth in pigeon pea (Cajanus cajan(L) Millsp.) at varions levels of P supply

“…This result suggests that the "pool size" of soluble-P in pigeon pea may be smaller than that of soybean at low-P conditions, reflecting on the more efficient utilization of soluble-P in pigeon pea compared to soybean. In this sense, soybean behaved similarly to white clover (Hart and Jessop 1983) which requires relatively high-P concentrations for high dry matter production and its growth at low-P availability is poor. Pigeon pea is probably capable of utilizing efficiently a limited amount of P by incorporating it into organic forms (residue-and lipid-P) as observed in Experiment 1.…”

“…Pigeon pea is probably capable of utilizing efficiently a limited amount of P by incorporating it into organic forms (residue-and lipid-P) as observed in Experiment 1. Pigeon pea which contains a small amount of soluble-P in the tissue behaved like lotus (Hart and Jessop 1983). The low soluble-P content in the tissues of pigeon pea at low-P conditions compared to soybean may be a criterion for the selection of species tolerant to low P environments.…”

Eficiência de absorção e utilização de fósforo em porta-enxertos cítricos

“…a EUP na Pa e raízes decresceu com o suprimento de P, especialmente nos tratamentos c 3 e c 4 (Quadro 1), confirmando a redução da eficiência de utilização com o aumento da disponibilidade de nutrientes (Elliot & White, 1994;sanginga at al., 2000), desde que os ganhos de biomassa não ocorrem na mesma magnitude em que os nutrientes são absorvidos e acumulados no tecido vegetal (marschner, 1995). Em condições de disponibilidade mais elevada ocorre o armazenamento de P no vacúolo na forma inorgânica (Hart & Jessop, 1983), o qual contribui para elevar o teor do nutriente na planta, porém sem participar diretamente de reações metabólicas e, ou, formação de estruturas (P orgânico), ao passo que, para plantas cultivadas em baixa disponibilidade, a fração presente no vacúolo contribui em menor proporção para o P total (furtini neto et al, 1998; martinez et al, 2005). Em condições de deficiência por P, a EUP é aumentada como resultado de alterações na atividade de enzimas na rota da glicólise, que passam a operar em vias alternativas no catabolismo de carboidratos durante a deficiência, contribuindo para uso mais eficiente do P por meio de reciclagem, redução de consumo e utilização de outras frações do nutriente (theodoru & Plaxton, 1993;shenoy & Kalagudi, 2005 discUssão os resultados obtidos confirmaram a hipótese do trabalho de que os PEs cítricos difeririam na EaP e EUP para a produção de biomassa da Pa e das raízes (Quadro 1).…”

A comparison of the response to phosphorus ofTrifolium repens‘Grasslands Huia’ and ‘Grasslands Tahora’ in a controlled environment

“…The corresponding initial soil pHs were 6.26, 6.24, 6.12, and 5.70. Other nutrients were added as described previously (Hart & Jessop 1983).…”