caa a22 4500 477112110 CHVBK 20180405111612.0 cr unu---uuuuu 170330e19960501xx s 000 0 eng 10.1007/BF00029057 doi (NATIONALLICENCE)springer-10.1007/BF00029057 Topa M. Boyce Thompson Institute for Plant Research, Tower Road, 14853-1801, Ithaca, NY, USA aut Seed source variation in 32P uptake in inus taeda L. seedlings: A possible regulation by efflux [Elektronische Daten] [M. Topa] Short-term 32P uptake experiments were conducted with intact seedlings of loblolly pine (Pinus taeda L.) to examine possible seed source variation in net accumulation of 32P in roots and shoots, and in rates of unidirectional influx. Seed source had a highly significant effect on biomass and P concentrations of shoots and roots. Seedlings from two seed sources representing fast-growing populations (a broadly-adapted and wet-site seed source) accumulated over 60% more total seedling P than smaller seedlings from a drought-hardy seed source, reflecting higher biomass and root P concentrations. Rates of unidirectional 32P influx in seedlings from the drought-hardy seed source were more than twice the rates of the seedlings from the broadly-adapted seed source. However, after 24 h in labeled uptake solution, net accumulation of 32P was similar, suggesting that rates of unidirectional efflux from roots of the drought-hardy seed source were also high. Although there were no significant differences in biomass and tissue P concentrations between the two fast-growing seed sources, rates of unidirectional influx in seedlings from the broadly-adapted seed source were 42% lower than rates in seedlings from the wet-site source. Yet, after 24 h in labeled uptake solution, net accumulation of 32P in seedlings from the broadly-adapted seed source was 50% higher. Unidirectional efflux out of the root may regulate net uptake of P as much, if not more, than influx in loblolly pine seedlings-at least under high-P growth conditions. The results in this study do not support previous studies with herbaceous plants suggesting that fast-growing species typically exhibit higher rates of nutrient uptake than slow-growing species. Kluwer Academic Publishers, 1996 growth nationallicence loblolly pine nationallicence 32P labeling nationallicence phosphorus efflux nationallicence phosphorus uptake nationallicence Pinus taeda L nationallicence Plant and Soil Kluwer Academic Publishers; gopher://gopher.wkap.nl 182/2(1996-05-01), 259-265 0032-079X 182:2<259 1996 182 11104 https://doi.org/10.1007/BF00029057 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00029057 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Topa M. Boyce Thompson Institute for Plant Research, Tower Road, 14853-1801, Ithaca, NY, USA aut NATIONALLICENCE 773 0- Plant and Soil Kluwer Academic Publishers; gopher://gopher.wkap.nl/ 182/2(1996-05-01), 259-265 0032-079X 182:2<259 1996 182 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer