The interactive effect of seasonal temperatures and water potential (Ψ) were examined on the germination of four co-occurring Eucalyptus species (Eucalyptus melanophloia F.Muell., E. pilligaensis Maiden, E. populnea subsp. bimbil L.A.S.Johnson & K.D.Hill and E. viridis R.T.Baker) from the Brigalow Belt South bioregion of New South Wales. These eucalypts are important canopy species, and are a key inclusion for restoring native vegetation to areas that have had significant landscape modification. Final germination, time to first germination, and time to 50% germination were recorded at three alternating temperature regimes for winter (day/night, 19/5°C), spring–autumn (27/12°C) and summer (34/20°C), and eight different Ψ treatments between saturation point (0 MPa) and permanent wilting point (–1.5 MPa) under controlled laboratory conditions. Final germination was highest in all species when seeds were incubated at winter conditions, but spring–autumn and summer temperatures had mixed effects on final germination, depending on the species. Final germination consistently declined with lower Ψ across all temperatures for E. pilliagaensis, E. populnea subsp. bimbil and E. viridis, whereas E. melanophloia displayed a mixed response to temperature and Ψ. No germination occurred when Ψ was lower than –0.25 MPa. Time to first germination and time to reach 50% germination (t₅₀) were lowest at summer temperatures for all species, and all species except E. pilligaensis experienced higher time to first germination and t₅₀ (i.e. slower germination rates) as Ψ decreased from 0 to –0.25 MPa. Our results indicate that all four eucalypts should be treated as drought-sensitive species with a higher probability of field recruitment during cooler and wet conditions.

检查上的四个共同存在的发芽季节温度和水势（Ψ）的交互效果桉树物种（桉树melanophloia桉。，E. pilligaensis少女，E.天牛亚种bimbil LASJohnson＆KDHill和E.贻贝RTBaker）来自新南威尔士州Brigalow Belt South生物区。这些桉树是重要的树冠物种，并且是将原生植被恢复到景观发生重大变化的地区的重要内容。在冬季（白天/夜晚，19/5°C），春季-秋季（27/12°C）和夏季（34 / 20°C），并在受控实验室条件下在饱和点（0 MPa）和永久萎wil点（–1.5 MPa）之间进行八种不同的处理。当种子在冬季条件下孵育时，所有物种的最终发芽率最高，但取决于物种，春秋季和夏季温度对最终发芽的影响混合。大肠杆菌（E. pilliagaensis），大肠杆菌（E. populnea）亚种。bimbil和E. viridis，而E. melanophloia显示出对温度和a的混合响应。当Ψ低于–0.25 MPa时，没有发芽。夏季温度下，所有物种的首次萌发时间和达到50％萌发的时间（t ₅₀）最低，除E. pilligaensis以外的所有物种都经历了更高的首次萌发时间和t ₅₀（发芽速度较慢）随着Ψ从0降低至–0.25 MPa。我们的结果表明，所有四个桉树都应被视为对干旱敏感的树种，在凉爽和潮湿的条件下，其田间募集的可能性更高。