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Biology subjects

Sumner, E. E.

Publications and source records attributed to Sumner, E. E..

2 recordsLinked to original sources

Trait - climate relations in Themeda triandra: a widely distributed C4 grass and crop wild relative

O_LIQuantifying relationships between traits and climate using plants collected from diverse climatic origins, grown under common conditions, potentially provides valuable insights into climate adaptation. C_LIO_LIWe report on fifteen accessions of kangaroo grass (Themeda triandra), a C4 species distributed across Australia, Asia, the Middle East and Africa from the Andropogoneae clade of grasses that is vital to global agriculture. Plants were grown to maturity in glasshouses under two thermal regimes, with ample water supplied. Numerous physiological, "economic" and developmental traits were characterised. C_LIO_LIAs expected, plants grown at 20{degrees}C maxima had lower photosynthetic rates (Asat) and dark respiration rates, reduced leaf expansion, and delayed flowering compared with plants grown at 30{degrees}C. However, surprisingly few traits varied with climate-of-origin: accessions from colder climates had higher Asat alongside lower leaf mass per area, but only when grown at 20{degrees}C; flowering time showed the strongest correlation with site climate, with plants from wetter, warmer or less variable climates taking longer to flower. C_LIO_LIOur findings highlight remarkable phenotypic flexibility in key traits of T. triandra; this flexibility is likely key to its wide distribution. The strong relationship between flowering time and climate-of-origin underscores the importance of reproductive phenology as an adaptive trait. C_LI

ecology↗

Linking drought strategy to climate of origin in a widespread C4 grass species: hydraulic traits, xylem anatomy and stomatal behaviour in Themeda triandra

O_LIHydraulic, stomatal and anatomical traits strongly influence drought survival and productivity, but the extent to which these trait-types are coordinated and relate to climate-of-origin in herbaceous species remains poorly understood. C_LIO_LIWe quantified hydraulic, stomatal and anatomical traits in eight populations of Themeda triandra selected from diverse temperature and precipitation regimes across Australia, grown under common conditions and exposed to drought. Trait - climate-of-origin relationships were quantified using multiple linear mixed models. C_LIO_LILeaf xylem embolism resistance (P50) was unrelated to climate-of-origin precipitation. Instead, plants from drier climates exhibited lower maximum stomatal conductance, earlier stomatal closure during drought and higher stomatal safety margins (the difference between water potential at stomatal closure and P50). Plants from warmer climates exhibited greater embolism resistance and higher hydraulic conductance, along with wider vessels and lower vein density, suggesting adaptation to high evaporative demand. C_LIO_LIOur findings highlight two primary hydraulic strategies related to climate-of-origin: 1) conservative water use and drought avoidance in drier climates, and 2) embolism resistance and hydraulic efficiency in warmer climates. These findings provide new insights into the intraspecific differences in traits and adaptive strategies used by C4 grasses to persist in contrasting climates. C_LI

ecology↗