Photosymbiotic giant clams are transformers of solar flux
Photosymbiotic giant clams are transformers of solar flux
复制标题
DOI：
10.1098/rsif.2014.0678
复制
发表时间：
2014-12-06
影响因子：
3.9
通讯作者：
Sweeney, Alison M.
中科院分区：
文献类型：
--
作者：
Holt, Amanda L.;Vahidinia, Sanaz;Sweeney, Alison M.
“巨型”tridacnid蛤已经进化出一个三维的，空间效率高的，光共生的光损伤预防系统。我们发现，巨蛤的外套膜组织，其中含有共生的营养提供微藻，包含一层虹彩细胞，称为虹彩细胞，用于通过横向和前向散射光到组织中来分配光合生产波长，同时用布拉格镜反射非生产波长。来自虹膜细胞的波长和角度依赖性散射在几何上耦合到垂直柱微藻，导致入射光沿着柱的侧面沿着均匀地重新分布，从而使得能够在组织深处进行光合作用。在clam系统的演化功能和电Transformer之间存在物理类比，其改变系统中单位面积的能量通量，同时保持总能量。在浅珊瑚礁上发现的入射光水平下，这种安排可以使蛤蜊系统内的藻类既有效地利用所有入射太阳能，又避免由于造礁珊瑚光共生中发生的非光化学猝灭而造成的光损伤和效率损失。组织内辐射测量和多尺度光学建模都支持我们对该系统的光物理学的解释。这种高度进化的“三维”生物光子系统提出了一种更有效，抗损伤的光伏材料和更空间有效的藻类生物燃料，食品和化学品的太阳能生产的战略。
'Giant' tridacnid clams have evolved a three-dimensional, spatially efficient, photodamage-preventing system for photosymbiosis. We discovered that the mantle tissue of giant clams, which harbours symbiotic nutrition-providing microalgae, contains a layer of iridescent cells called iridocytes that serve to distribute photosynthetically productive wavelengths by lateral and forward-scattering of light into the tissue while back-reflecting non-productive wavelengths with a Bragg mirror. The wavelength-and angle-dependent scattering from the iridocytes is geometrically coupled to the vertically pillared microalgae, resulting in an even re-distribution of the incoming light along the sides of the pillars, thus enabling photosynthesis deep in the tissue. There is a physical analogy between the evolved function of the clam system and an electric transformer, which changes energy flux per area in a system while conserving total energy. At incident light levels found on shallow coral reefs, this arrangement may allow algae within the clam system to both efficiently use all incident solar energy and avoid the photodamage and efficiency losses due to non-photochemical quenching that occur in the reef-building coral photosymbiosis. Both intra-tissue radiometry andmultiscale optical modelling support our interpretation of the system's photophysics. This highly evolved 'three-dimensional' biophotonic system suggests a strategy for more efficient, damage-resistant photovoltaic materials and more spatially efficient solar production of algal biofuels, foods and chemicals.