Comments |
P.10 right column 3rd paragraph: "Hives also maintain a relatively constant temperature. Recent research has demonstrated that leaves themselves on trees ranging from boreal to the sub-tropical maintain a relatively common internal temperature of 21.4 ± 2.2°C [primary source]. This is an approximate optimum for photosynthesis, the external temperature of the boreal to sub-tropical averages ranged from 12° to 26°C. There are six ways known that help to maintain this apparent homeostasis to either cool or warm the leaf. The internal leaf temperature is regulated by manipulation of leaf blade orientation, control of stomatal aperture, chloroplast movement inside cells, changes in leaf hairiness and wax reflectance and numbers of leaves on branches [refs 2,105–111]. The first three may take only some 15 min to change, the next two several days, and the final one maybe a week or two. Communication and feedback must be at the basis of these coordinate changes but what is communicated remains unknown at present. The coordinated events represent adaptive and thus intelligent plasticity. Those who more accurately assess the particular circumstances and deploy the optimal set of controls provide a greater probability of ultimate fitness." |