Water relations balance parameters of 30 woody species from Cerrado vegetation in the wet and dry season

Abstract

The water relations balance parameters of plant tissue have been determined under field condition. They are the osmotic potentials at saturation (πsat), the osmotic potentials at the turgid loss point (πtlp), modulus of elasticity (ε) and the water saturation deficiency at turgid loss point (Wsdtlp) of 30 adult woody species from Cerrado vegetation (neotropical savanna) in the wet and dry seasons of Brazil. And the changing patterns ofSe values of each species have been compared and analyzed in different methods. The mean values of πsat, πtlp, ε andWsdtlp of 30 species in the wet season were −2.11 MPa, −2.50 MPa, 19.66 MPa and 10.27% respectively. Responding to water stress in the dry season, the values of πsat of 24 species, the πtlp and the ε of 17 species, theWsdtlp of 6 species significantly went down or up comparing with those in the wet season (P<0.05). Only 3 species had not changed their water parameters significantly any more. The mean values of πsat, πtlp, ε andWsdtlp of 30 species were adjusted to be −2.28 MPa, −2.84 MPa, 18.58 MPa and 8.19% respectively. The species that have lower values of the πsat have higher values on ε. Contrary, the species that have higher values on the πsat have lower values on ε. The special strategies of 30 Cerrado species have been divided into 3 types in Cluster Analysis Method. Every type has the distinct water balance mechanism and the parameter-adjusting pattern.

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