Polyploidy but Not Range Size Is Associated With Seed and Seedling Traits That Affect Performance of Pomaderris Species.

Ploidy and species range size or threat status have been linked to variation in phenotypic and phenological seed and seedling traits, including seed size, germination rate (speed) and seedling stature. There is surprisingly little known about the ecological outcomes of relationships between ploidy, key plant traits and the drivers of range size. Here we determined whether ploidy and range size in Pomaderris, a genus of shrubs that includes many threatened species, are associated with variation in seed and seedling traits that might limit the regeneration performance of obligate seeders in fire-prone systems. We experimentally quantified seed dormancy and germination processes using fire-related heat treatments and evaluated seedling performance under drought stress. We also examined the association of seed size with other seed and seedling traits. Polyploids had bigger seeds, a faster germination rate and larger and taller seedlings than diploids. There was a lack of any clear relationship between range size and seed or seedling traits. The ploidy effects observed for many traits are likely to be indirect and associated with the underlying seed size differences. These findings indicate that there is a higher potential competitive advantage in polyploid than diploid Pomaderris during regeneration, a critical stage in the post-fire environment. This insight to the regeneration phase may need to be considered when planning and prioritising management of threatened species.

Understanding depressive rumination from a mood-as-input perspective: effects of stop-rule manipulation.

The current study tested the mood-as-input hypothesis account of perseverative rumination in 25 participants with a diagnosis of major depressive disorder and 25 healthy controls. It also examined the factors underlying mood changes within a bout of rumination and their relations with trait rumination and metacognitive beliefs about rumination. A structured rumination interview was used to facilitate participants' reflection on two previous depressive incidents while deploying a specific stop-rule for the task (either a goal-guided or feeling-guided stop-rule). As predicted by the mood-as-input hypothesis, perseveration exhibited by depressed participants was affected by the interaction between diagnosis and stop-rule, with levels of perseveration being greatest when depressed participants used the goal-guided stop-rule. Increases in negative mood over the rumination interview were shown to be influenced only by participants' diagnostic status, regardless of their stop-rule. Compared to healthy controls, depressed participants also reported a preferential use of the goal-guided stop-rule in response to negative mood states in their daily lives. The findings about the dependence of rumination on stop-rule use within the depressed sample support the use of metacognitive treatment approaches in which patients are encouraged to challenge negative beliefs about the controllability of rumination.