英國科學(xué)家日前發(fā)現(xiàn),，一些植物之所以在秋天變紅,，很可能是為了躲避害蟲侵害。
倫敦帝國學(xué)院托馬斯·多雷博士和吉姆·哈迪教授在實驗中用了70種不同顏色對比秋天在植物上產(chǎn)卵的蚜蟲更偏愛其中哪一類顏色,。結(jié)果發(fā)現(xiàn),，蚜蟲對紅色系的葉子最不感興趣,，而黃色葉子對蚜蟲的吸引力則大得多。
多雷分析說,，植物葉片變紅是因為花青素的作用,，而變黃是葉綠素分解、葉黃素和胡蘿卜素顏色顯現(xiàn)造成的,。并不是所有植物葉子都在秋天變紅,，這是因為“如果（這個品種）被昆蟲襲擊的可能性較大，可能造成的損失大于在秋天制造花青素的代價,，植物會選擇變紅,。而如果感染蟲害的可能性較低，植物就會保持黃色”,。
多雷說,，昆蟲的眼睛并不能分辨紅色，但實驗結(jié)果證明紅色對于蚜蟲確實具有防御功效,，這讓他感到“非常困惑”,。
這項研究成果發(fā)表在最新一期英國《皇家學(xué)會學(xué)報B》（Proceedings of the Royal Society B）上。（生物谷Bioon.com）
生物谷推薦原始出處：
Proceedings of the Royal Society B,，DOI：10.1098/rspb.2008.0858,，Thomas F. D?ring，Jim Hardie
Autumn leaves seen through herbivore eyes
Thomas F. D?ring1, 2, Marco Archetti3, Jim Hardie1
1Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK
2 School of Biological and Chemical Sciences, Queen Mary, University London, London E1 4NS, UK
3Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
Why leaves of some trees turn red in autumn has puzzled biologists for decades, as just before leaf fall the pigments causing red coloration are newly synthesized. One idea to explain this apparently untimely investment is that red colour signals the tree's quality to herbivorous insects, particularly aphids. However, it is unclear whether red leaves are indeed less attractive to aphids than green leaves. Because aphids lack a red photoreceptor, it was conjectured that red leaves could even be indiscernable from green ones for these insects. Here we show, however, that the colour of autumnal tree leaves that appear red to humans are on average much less attractive to aphids than green leaves, whereas yellow leaves are much more attractive. We conclude that, while active avoidance of red leaves by aphids is unlikely, red coloration in autumn could still be a signal of the tree's quality, or alternatively serve to mask the over-attractive yellow that is unveiled when the green chlorophyll is recovered from senescing leaves. Our study shows that in sensory ecology, receiver physiology alone is not sufficient to reveal the whole picture. Instead, the combined analysis of behaviour and a large set of natural stimuli unexpectedly shows that animals lacking a red photoreceptor may be able to differentiate between red and green leaves.
