Record ID No. |
2073 |
Author(s) |
Ryan M. H., Ehrenberg S., Bennett R.G., Tibbett M. , 2009 |
Affiliation |
University of Western Australia, Sch Plant Biol, M081, 35 Stirling Hwy, Crawley, WA 6009, Australia |
Title |
Putting the P in Ptilotus: a phosphorus-accumulating herb native to Australia |
Source. Vol.(no):Page |
Annals of Botany. 103(6): 901-911p. |
Categories |
Arbuscular Mycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Country |
Australia |
Abstracts |
Ptilotus polystachyus (green mulla mulla; ptilotus) is a short-lived perennial herb that occurs
widely in Australia in arid and semi-arid regions with nutrient poor soils. As this species shows potential for
domestication, its response to addition of phosphorus (P) and nitrogen (N) was compared to a variety of the
domesticated exotic perennial pasture herb Cichorium intybus (chicory), 'Puna'. Pots were filled with 3 kg of
an extremely nutrient-deficient sterilized field soil that contained 3 mg kg(-1) mineral N and 2 mg kg(-1)
bicarbonate-extractable P. The growth and P and N accumulation of ptilotus and chicory in response to seven
rates of readily available phosphorus (0-300 mg P pot(-1)) and nitrogen (N) (0-270 mg N pot(-1)) was examined.
Ptilotus grew extremely well under low P conditions: shoot dry weights were 23, 6 and 1.7 times greater than
for chicory at the three lowest levels of P addition, 0, 15 and 30 mg P pot(-1), respectively. Ptilotus could
not downregulate P uptake. Concentrations of P in shoots approached 4 % of dry weight and cryo-scanning
electron microscopy and X-ray microanalysis showed 35-196 mm of P in cell vacuoles in a range of tissues from
young leaves. Ptilotus had a remarkable tolerance of high P concentrations in shoots. While chicory exhibited
symptoms of P toxicity at the highest rate of P addition (300 mg P pot(-1)), no symptoms were present for
ptilotus. The two species responded in a similar manner to addition of N. In comparison to chicory, ptilotus
demonstrated an impressive ability to grow well under conditions of low and high P availability. Further study
of the mechanisms of P uptake and tolerance in ptilotus is warranted. |