The Growth of Kentucky Bluegrass ( Poa pratensis cv. Plush) as Affected by Plant Growth Regulators and Iron (Fe), Grown under Limited Soil Moisture Regimes

摘要

This research was conducted to determine if exogenous plant growth regulators (PGR) or Fe could alleviate some of the effect of low soil moisture content on Kentucky blue grass ( Poa pratensis cv. Plush). Two week old seedlings were treated with seaweed ( Ascophyllum nodosum ) extract (SWE) at 9.3 L ha^-1 or Propiconalzole (PPC) alone at 0.93 L active ingredient (a.i) ha^-1 alone or in combination with chelated Fe at 1.1 kg ha^-1. Transplanted seedlings were grown under three soil moisture regimes (-0.5, -0.3 and -0.03 MPa) for 6 weeks. The experiment was repeated once. Foliage growth of the treated plants increased as soil water potential increased. Application of Fe provided the most consistent enhancement of foliage growth regardless of the soil moisture regimes. All PGR treatments improved leaf water content compared with control plants. Root length and root mass measurements made in the difference experiments were positively correlated. However, root length decreased significantly with soil moisture level; while root mass did not. The results showed that exogenous application of SWE or PPC, alone or with Fe reduced the influence of low soil moisture content . Seedlings did not differ in P and K contents in leaf tissues regardless of the soil moisture regimes or PGR treatments. The results indicate that the main effects of the PGR on growth of Kentucky bluegrass under low soil moisture content were associated with aspects other than P and K nutrition.