CHANGES IN THE PHOSPHORUS COMPOSITION OF SEEDS OFHAKEA SERICEA(PROTEACEAE) DURING GERMINATION UNDER LOW PHOSPHORUS CONDITIONS

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Abstract
Summary: Seeds ofHakea sericeaSchrad belonging to the subfamily Grevilleoideae of the Proteaceae greater P reserves than those belonging to the Proteoideae indigenous to South Africa. The main P‐containing compounds in seeds ofH. sericeaare phytic acid with smaller proportions consisting of lipid‐P, RNA, DNA, protein‐P, polyphosphate and orthophosphateHakea sericeagrew on sterile acid washed sand for up to 125 d after sowing before signs of mineral deficiency symptoms appeared. Proteoid roots were produced by seedlings grown in Clovelly sand from 60 d after sowing and their numbers appeared to be related to the accumulation of P in the seedling. It is concluded that the P reserves of seeds ofH. sericeamay provide a competitive advantage over those of the Proteoideae for establishment and growth in the acidic sandy soils of the south‐western Cape, South Africa.