Polyembryony in Erythronium americanum

Source–sink imbalance increases with growth temperature in the spring geophyte Erythronium americanum

Spring geophytes produce larger storage organs and present delayed leaf senescence under lower growth temperature. Bulb and leaf carbon metabolism were investigated in Erythronium americanum to identify some of the mechanisms that permit this improved growth at low temperature. Plants were grown under three day/night temperature regimes: 18/14 °C, 12/8 °C, and 8/6 °C. Starch accumulated more sl...

The alternative respiratory pathway allows sink to cope with changes in carbon availability in the sink-limited plant Erythronium americanum.

Mechanisms that allow plants to cope with a recurrent surplus of carbon in conditions of imbalance between source and sink activity has not received much attention. The response of sink growth and metabolism to the modulation of source activity was investigated using elevated CO(2) and elevated O(3) growth conditions in Erythronium americanum. Sink activity was monitored via slice and mitochond...

Polyembryony in Armadillos

O travelers passing through the southern US. may be struck by the unusual appearance of the ninebanded armadillo (Dasypus novemcinctus). This animal, which is about threequarters of a meter long, canbe identified by the leathery plates of armor that cover it nearly from the tip of its nose to the end of its tail. It also has a seriesof transverse plates that wrap around its midsection, giving i...

Polyembryony in Hierochloe Odorata (l.) Beauv

The evolution of polyembryony in parasitoid wasps.

Polyembryony has evolved independently in four families of parasitoid wasps. We review three main hypotheses for the selective forces favouring this developmental mode in parasitoids: polyembryony (i) reduces the costs of egg limitation; (ii) reduces the genetic conflict among offspring; and (iii) allows offspring to adjust their numbers to the quality of the host. Using comparative data and ve...