Phosphorus nutrition and mycorrhiza effects on grass leaf growth. P status- and size-mediated effects on growth zone kinematics.
This study tested whether leaf elongation rate (LER, mm h(-1)) and its components--average relative elemental growth rate (REGRavg, mm mm(-1) h(-1)) and leaf growth zone length (L(LGZ), mm)--are related to phosphorus (P) concentration in the growth zone (P(LGZ) mg P g(-1) tissue water) of Lolium perenne L. cv. Condesa and whether such relationships are modified by the arbuscular mycorrhizal fungus (AMF) Glomus hoi. Mycorrhizal and non-mycorrhizal plants were grown at a range of P supply rates and analysed at either the same plant age or the same tiller size (defined by the length of the sheath of the youngest fully expanded leaf). Both improved P supply (up to 95%) and AMF (up to 21%) strongly increased LER. In tillers of even-aged plants, this was due to increased REGRavg and L(LGZ). In even-sized tillers, it was exclusively due to increased REGRavg. REGRavg was strictly related to P(LGZ) (r2 = 0.95) and independent of tiller size. Conversely, L(LGZ) strictly depended on tiller size (r2 = 0.88) and not on P(LGZ). Hence, P status affected leaf growth directly only through effects on relative tissue expansion rates. Symbiosis with AMF did not modify these relationships. Thus, no evidence for P status-independent effects of AMF on LER was found.
Kavanová
Monika
M
Lehrstuhl für Grünlandlehre, Technische Universität München, Am Hochanger 1, D-85350 Freising-Weihenstephan, Germany.
Grimoldi
Agustín A
AA
Lattanzi
Fernando A
FA
Schnyder
Hans
H
D001696:Biomechanical Phenomena; D008129:Lolium / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology; D038821:Mycorrhizae / Q000502:physiology*; D010758:Phosphorus / Q000378:metabolism*; D018515:Plant Leaves / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology
D010758:Phosphorus