ABSTRACT

Basidiomycete fungi eject basidiospores using a surface tension catapult. A fluid drop forms at the base of each spore and, after reaching a critical size, coalesces with the spore and launches it from the gill surface. It has long been hypothesized that basidiomycete fungi pack the maximum number of spores into a minimal investment of biomass. Building on a nascent understanding of the physics underpinning the surface tension catapult, we modeled a spore’s trajectory away from a basidium and demonstrated that to achieve maximum packing the size of the fluid drop, the size of the spore, and the distance between gills must be finely coordinated. To compare the model with data, we measured spore and gill morphologies from wild mushrooms and compared measurements with the model. The empirical data suggest that in order to pack the maximum number of spores into the least amount of biomass, the size of Buller’s drop should be smaller but comparable to the spore size. Previously published data of Buller’s drop and spore sizes support our hypothesis and also suggest a linear scaling between spore radius and Buller’s drop radius. Morphological features of the surface tension catapult appear tightly regulated to enable maximum packing of spores. If mushrooms are maximally packed and Buller’s drop radii scale linearly with spore radii, we predict that intergill distance should be proportional to spore radius to the power 3/2.

摘要

担子菌真菌使用表面张力弹射器喷射担子孢子。在每个孢子的底部形成一滴液滴，在达到临界尺寸后，与孢子结合并将其从鳃表面发射。长期以来一直假设担子菌将最大数量的孢子打包成最少的生物量投资。基于对支撑表面张力弹射器的物理学的初步理解，我们模拟了孢子远离 basium 的轨迹，并证明要实现最大的堆积，液滴的大小、孢子的大小和鳃之间的距离必须是精细协调。为了将模型与数据进行比较，我们测量了野生蘑菇的孢子和鳃形态，并将测量结果与模型进行了比较。经验数据表明，为了将最大数量的孢子装入最少的生物质中，布勒水滴的大小应该更小但与孢子大小相当。先前公布的布勒液滴和孢子大小的数据支持我们的假设，并表明孢子半径和布勒液滴半径之间存在线性比例。表面张力弹射器的形态特征似乎受到严格调节，以实现孢子的最大堆积。如果蘑菇被最大程度地填充并且布勒的下落半径与孢子半径成线性比例，我们预测鳃间距离应该与孢子半径的 3/2 次方成正比。先前公布的布勒液滴和孢子大小的数据支持我们的假设，并表明孢子半径和布勒液滴半径之间存在线性比例。表面张力弹射器的形态特征似乎受到严格调节，以实现孢子的最大堆积。如果蘑菇被最大程度地填充并且布勒的下落半径与孢子半径成线性比例，我们预测鳃间距离应该与孢子半径的 3/2 次方成正比。先前公布的布勒液滴和孢子大小的数据支持我们的假设，并表明孢子半径和布勒液滴半径之间存在线性比例。表面张力弹射器的形态特征似乎受到严格调节，以实现孢子的最大堆积。如果蘑菇被最大程度地填充并且布勒的下落半径与孢子半径成线性比例，我们预测鳃间距离应该与孢子半径的 3/2 次方成正比。