Mangrove progapules stand up for themselves!

We have all heard that Rhizophora propagules fall from the trees when they are ripe and impale themselves in the mud, giving rise to the new generation of strong young plants.

But we also all know that a lot of them miss. They float away, or they bounce, or whatever, but eventually end up lying on their sides in the mud. Or, they may get somewhere in a mostly vertical way, and fall over, or get stepped on and knocked over. What happens to these poor babies?

Scientists at the University of Illinois now have the answer. (I've always wanted to write things like that). In a model dwarf zone, peat based greenhouse system, they laid two propagules in the peat.

One of them was on the surface, with the very short roots that had already formed just on the peat. The other was buried lyiing down, with just its apical bud and about 8 cm of hypocotly exposed.

This started on a Tuesday, and the nursery was checked before the weekend. When the scientists came back on Monday, they noticed two things. First, the plant just on the surface was standing up, though its "shadow" in the peat was still there. It took the better part of a week to determine for sure that no "helpful" greenhouse person had tampered with it, but none had.

It simply stood up At the end of that week, the scientists dug it up, and found that all the roots that had arisen on the "top" side had curved down and pulled it up using the base of the hypocotyl as a fulcrum. Of course scientists are perverse sorts of people, so they turned it over, and put it back down (photo). Keep tuned for later developments.


Meanwhile, what happened to the half-buried sibling? Apparently, there is either some signal about being exposed, or there is just too much mechanical resistance to lifting, so it didn't stand up. What it did, however, was curve! The scientists were quite astonished that the hypocotyl could still grow this way. Now they are eagerly awaiting bud burst, to see if it has survived the struggle.