Editor's Note
Alfred Bennett's article in
Nature
's first issue on fertilisation in winter-flowering plants made much mention of work on plant fertilisation by Charles Darwin. Following the publication of that paper, Darwin drew Bennett's attention to various small errors and clarifications. Thus Bennett got a letter in
Nature
's second issue to address Darwin's points, notably that
Vinca
(periwinkle) absolutely requires the attention of insects for pollination. Bennett went back to his notes and found that Darwin was, of course, right—apparently self-fertile periwinkles do not set fruit in the winter.
MR. Darwin has done me the honour of calling my attention to one or two points in my paper, published in your last number, “On the Fertilisation of Winter-Flowering Plants”. He thinks there must be some error in my including
Vinca major
among the plants of which the pollen is discharged in the bud, as he “knows from experiment that some species of
Vinca
absolutely require insect aid for fertilisation.” On referring to my notes, I find them perfectly clear with respect to the time at which the pollen is discharged. My observation, however, so far agrees with Mr. Darwin’s, that I find no record of any fruit being produced in January; it was, in fact, the absence of capsules on the
Vinca
which induced me to qualify the sentence on this subject, and to say “in nearly
all
these cases, abundance of fully formed seed-bearing capsules were observed.” It is worthy of remark, that the
Vinca
is the only species in my list of apparently bud-fertilised plants not indigenous to this country. The second point relates to the white dead-nettle, with respect to which Mr. Darwin says, “I covered up
Lamium album
early in June, and the plants produce no seed, although surrounding plants produced plenty.” This again would agree with my conjecture that it is only the flowers produced in winter that are self-fertilised. I may, however, be permitted to suggest that the test of covering up a plant with a bell-glass is not conclusive on the point of cross-fertilisation, as it is quite probable that with plants that are ordinarily self-fertilised, the mere fact of a complete stoppage of a free circulation of air may prevent the impregnation taking place. Has the experiment ever been tried with grasses, which, according to the French observer, M. Bidard are necessarily self-fertilised?
(
1
, 58; 1869)
Alfred W. Bennett: 3, Park Village East, Nov. 8, 1869.
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编者按
阿尔弗雷德·贝内特在《自然》的第1期上发表了一篇关于冬季开花型植物受精作用的论文,该论文中大量提到了查尔斯·达尔文关于植物受精作用的研究工作。在贝内特的论文发表后,达尔文提请贝内特注意文章中存在的多处小错误,并请他作一些说明。于是,在这篇发表于《自然》第2期的快报文章中,贝内特公布了达尔文的观点,即长春花的传粉完全需要昆虫的参与。贝内特在重新查阅了他的记录后发现,达尔文的观点确实是正确的,很显然自花受精型的长春花在冬天是不结果的。
在贵刊的上一期中有一篇我发表的论文——《论冬季开花型植物的受精作用》。我很荣幸达尔文先生给了我一些提醒,让我注意到该文中的一两个问题。我在论文中提到,大蔓长春花是一种在花蕾中就有花粉散落出来的植物,他认为这种说法肯定存在某些错误,因为他“由实验得知,长春花属的某些种只有在昆虫的辅助下才能完成受精。”于是我再次查阅了我的记录,发现关于花粉释放时间的记录是非常清楚的。不过,到目前为止,我的观察结果与达尔文先生的是一致的,因为我并没有发现长春花属的植物在1月结果的任何记录。事实上,正是长春花属的植物没有结出蒴果这一现象让我仔细考虑了该如何用文字来表述这个问题,后来我写下了“几乎
所有
我们观察到的植物都产生了大量完全成形的结有种子的蒴果”这句话。需要说明的是,长春花属是我观察到的花蕾受精植物中唯一一种非本土的植物。第二点是与短柄野芝麻有关的问题。对于这方面,达尔文先生说:“我在6月初将一株短柄野芝麻罩住,当它周围的植物都硕果累累的时候,它却并没有结出任何种子。”这再一次与我提出的只有冬季开花型植物才能自花受精的推测相吻合。不过,请允许我提出如下建议:用钟形玻璃罩罩住植物以检验异花受精的方法并不完全可信,因为这样对于本来是自花受精的植物来说,很可能会由于完全中断了空气的自由流通而阻止受精作用的发生。这不就是当初法国观察者比达尔自以为是地认为肯定发生了自花受精所依据的那个用稻科植物进行的实验吗?
(刘皓芳 翻译;刘京国 审稿)
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