树桩如何无限期存活

A living stump sounds like something out of a horror movie.
一个活着的树桩,听起来像是恐怖电影才会有的东西。
In fact, it is not unusual for a tree, deprived of its trunk and foliage by lightning, disease or a lumberjack,
事实上,这对一棵被闪电、疾病或伐木工人夺去树干和树叶的树来说并不稀奇,
but still possessed of roots and an above-ground stump, to continue a zombie-like existence for years—even decades.
这些树仍有树根和在地面上的残余,它们可以像僵尸一样存活数年,甚至数十年。
Such arboreal undead have been recognised since 1833.
这种树栖不死生物自1833年就被发现了。
But surprisingly, until now, no living stump has been subjected to detailed scientific scrutiny.
但令人惊讶的是,直到现在都没有对这种活着的树桩的详细科学检查。
The scrutinised stump, pictured above, is the remains of a Kauri tree in Waitakere Ranges Regional Park, New Zealand.
上图中经过仔细检查的树桩是新西兰怀特克雷山脉地区公园里一棵贝壳杉的残余部分。
It and two neighbouring, intact, Kauris were investigated by Martin Bader and Sebastian Leuzinger of Auckland University of Technology,
奥克兰理工大学的Martin Bader和Sebastian Leuzinger研究了这颗树桩以及周围两棵完整的贝壳杉,
who have just published their results in iScience.
他们刚在《iScience》发表了他们的研究结果。
Dr Bader and Dr Leuzinger started with the suspicion that living stumps are sustained through their roots by nearby, intact trees of the same species.
Bader和Leuzinger博士开始怀疑活着的树桩是靠着附近同种完整树木的树根支撑着的。

Above ground, trees look like distinct entities, but below the surface things get more complicated.
在地面上,树木看起来像像是不同的实体,但在地面下,事情变得更加复杂。
More than 150 tree species, Kauris among them, are known to have roots that sometimes fuse with those of other members of the same species.
包括贝壳杉在内的150多种树木,它们的树根有时会和同一物种中其他成员的树根交缠。
Such subterranean junctions permit exchange between individual trees of food, water, minerals and even micro-organisms,
这种地下的连接允许食物、水、矿物质甚至微生物在树木之间进行交换
to create what some regard as a superorganism.
以创造出一些人认为是超个体的东西。
The question the researchers asked was: if a tree in such a network were reduced to a stump,
研究人员提出的问题是:如果这一网络中的一棵树被砍成树桩,
would that remnant quickly be cut loose as useless and left to fend for itself?
剩余的部分会很快被认为是一种无用的东西被抛弃或让其自生自灭吗?
Their study, carried out over the course of nine days, proved that the stump under scrutiny was still a participating member of the local superorganism.
他们的研究进行了9天,研究证明经过仔细检查的树桩仍然是本地超个体中一位参与成员。
Sensors fitted to the two intact trees and the stump showed that the stump's flow of sap and water ran inversely to that of the trees.
安装在两棵完整的树和树桩上的传感器显示,树桩液流和水的流量与树木的流量成反比。
On sunny days, when the intact trees were photosynthesising extensively and drawing a great deal of water up their trunks,
在阳光明媚的日子里,完整的树木会进行广泛的光合作用,把大量的水分吸到树干上
there was almost no water movement in the stump. At night, when the trees were no longer transpiring in this way,
而树桩里几乎没有水的流动。在夜晚,当树木不再以这种方式蒸发水分时,
water flooded into the stump and sap flow reached a maximum, indicating that it was receiving a burst of resources.

流入树桩的水和液流达到最大值,表明它接收到了大量的资源。

Exactly why a stump's neighbours dole out their hard-won nutrients in this manner remains a mystery, but Dr Bader and Dr Leuzinger have ideas.
为什么树桩的邻居们会以这种方式少量发放自己辛苦得来的营养仍是个谜,但Bader和Leuzinger博士有自己的想法。
Biologists know of two ways co-operation between organisms can evolve.
生物学家知道生物体之间有两种合作可以进化。
One is kin selection, which requires the collaborators to be related (as neighbouring trees of the same species are likely to be)
一种是亲缘选择,要求合作者相互联系(就像邻近的同种树木一样)
and works if sacrifices by one bring disproportionate reproductive benefits to others.
如果一方给另一方带来不成比例的繁殖优势,这种方式就会奏效。
The effect of this is to propagate a collaborator's genes collaterally,
这种方法的效果是间接地传播合作者的基因
in a way that sociologists might refer to as nepotism, instead of directly from parent to offspring.
在某种程度上,社会学家或许称为裙带关系,而非直接从父母传给后代。
This may be why root connections happen in the first place, but cannot explain their perpetuation,
这或许是根系连接首先发生的原因,但这无法解释它们的存活,
for trying to help a trunkless stump reproduce would be a fool's errand.
因为尝试帮助没有树干的树桩繁殖是徒劳的。

树桩如何无限期存活(2).jpg

The other route to co-operation is reciprocal altruism of the "you scratch my back and I'll scratch yours" variety.
另一种合作方式是互惠利他主义,即“你帮我,我帮你”。
This requires a stump's neighbours, which are feeding it, to benefit directly from the arrangement.
这要求树桩附近向它运输营养的邻居直接从这种配植中获益。
The suggestion Dr Bader and Dr Leuzinger make is that they do—
Bader和Leuzinger博士认为它们确实这么做了—
the stump's role being to extend, at minimal cost, the root networks of its intact neighbours.
树桩的角色是以最小的代价扩张其完整邻居的根系网络。
From their point of view, that makes keeping the stump alive worthwhile.
从他们的角度来看,这使得树桩的存活是值得的。
If this is what is going on, however, it is a good illustration of the dangers of anthropomorphic terminology.
然而,若事实如此,那么这就很好地说明了拟人术语的危险。
The arrangement might look reciprocal to human eyes, because it is keeping the stump alive.
这种配植可能看起来与人类的眼睛是对等的,因为它保持了树桩的活性。
But since the stump cannot reproduce it might as well, in Darwinian terms, be dead anyway,
但既然树桩不能繁殖,用达尔文的话说,它还是有可能会死掉,
for it garners no evolutionary benefit from its survival. Unless, of course, to go back to the idea of kin selection,
因为它没有从它的生存中获得进化上的好处。当然,除非回到亲缘选择的概念,
the neighbours it is sustaining are its kin and it is rendering nepotistic assistance to them from beyond the grave.
它所扶养的邻居是它的亲戚并且它在死后向它们提供裙带关系的援助。

来源:经济学人

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