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JXB:为何C4光合作用比较少出现在树木中?

已有 338 次阅读 2020-5-21 08:22 |个人分类:每日摘要|系统分类:论文交流

Why is C4 photosynthesis so rare in trees?

第一作者Sophie N R Young

第一单位英国兰卡斯特大学

通讯作者Marjorie R Lundgren


 Abstract 


背景回顾Since C4 photosynthesis was first discovered over 50 years ago, researchers have sought to understand how this complex trait evolved from the ancestral C3 photosynthetic machinery on more than 60 occasions. 

Box 1. C4 photosynthesis arises from both anatomical and biochemical modifications to the ancestral C3 photosynthetic system.


提出问题:Despite its repeated emergence across the plant kingdom, C4 photosynthesis is notably rare in trees, with true C4 trees only existing in Euphorbia


结果:Here we consider aspects of the C4 trait that could limit but not preclude the evolution of a C4 tree, including reduced quantum yield, increased energetic demand, reduced adaptive plasticity, evolutionary constraints, and a new theory that the passive symplastic phloem loading mechanism observed in trees, combined with difficulties in maintaining sugar and water transport over a long pathlength, could make C4 photosynthesis largely incompatible with the tree lifeform. 


结论:We conclude that the transition to a tree habit within C4 lineages as well as the emergence of C4 photosynthesis within pre-existing trees would both face a series of challenges that together explain the global rarity of C4 photosynthesis in trees. The C4 trees in Euphorbia are therefore exceptional in how they have circumvented every potential barrier to the rare C4 tree lifeform.


 摘  要 


自从50年前首次发现C4光合作用以来,研究人员一直想要了解这种复杂的性状是如何从C3光合作用机制演化而来的,并且在不同植物支系中独立演化了至少60次。虽然C4光合在整个植物界反复出现,但是其在树木中存在的情况比较稀少,目前已知的只有大戟属植物。本文中,作者考察了C4性状的某些特性可能会限制但并不会完全排除C4树木的演化,包括光合作用量子产量的降低,能量需求的增加,适应可塑性的降低以及演化上的限制。另外,在树木中新观察到的被动共生韧皮部加载机制,加上难以在较长的运输途中维持糖和水的转运,这些可能会使得C4光合作用并不适用于树木的生命形式。作者认为C4植物支系演化成树木,或是在树木中形成C4光合机制都将面临一系列的挑战,解释了全球C4树木的稀缺性。因此,大戟属植物中的C4树木巧妙的规避了C4光合机制对于树木生命形式带来的潜在屏障。


 通讯作者 


**Marjorie R Lundgren**


个人简介:

2015年,谢菲尔德大学,博士。


研究方向:

通过植物生态生理学和系统地理学的方法来理解各种光合作用系统的演化


doi: 10.1093/jxb/eraa234


Journal: Journal of Experimental Botany

Published date: May 15, 2020


p.s. 植物C4光合相关研究链接:



http://blog.sciencenet.cn/blog-3158122-1234180.html

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