. Grundlagen der Botanik. ofplants stark cutinized haben Oberflächen und Ofthose Die nicht haben. Abb. 121, jedoch conveysome Begriff der Unterschied zwischen den beiden Arten ofstructure. In mostcases, wie in Indien - Gummibaum, der externen epidermalen Zellen (und oft zwei Schichten von orthree arefilled cellsbeneath Diese) mit Wasser und j^ dienen damit als Reser-voirs, aus denen hebendie äußeren Teile des leafand der Stammzellen sind attimes geliefert. In vielen Fällen ist spürbar in der Kohl, der epidermisis mit Wachsartiger Beschichtung, die zweifellos increasesthe Leistung des Blattes zu behalten Moi abgedeckt

• Bildanbieter: The Reading Room / Alamy Stock Foto
• Bild-ID: 2AG9P33
• Dateigröße: 7,2 MB (225,5 KB Komprimierter Download)
• Freigaben (Releases): Model - nein | Eigentum - nein
• Format: 1810 x 1381 px | 30,6 x 23,4 cm | 12,1 x 9,2 inches | 150dpi

Weitere Informationen

Dieses Bild ist ein gemeinfreies Bild. Dies bedeutet, dass entweder das Urheberrecht dafür abgelaufen ist oder der Inhaber des Bildes auf sein Urheberrecht verzichtet hat. Alamy berechnet Ihnen eine Gebühr für den Zugriff auf die hochauflösende Kopie des Bildes.

Dieses Bild kann kleinere Mängel aufweisen, da es sich um ein historisches Bild oder ein Reportagebild handel

. Foundations of botany. ofplants which have strongly cutinized surfaces and ofthose which have not. Fig. 121, however, may conveysome notion of the difference between the two kinds ofstructure. In mostcases, as in the india-rubber tree, the ex-ternal epidermal cells(and often two orthree layers of cellsbeneath these) arefilled with water, and j^thus serve as reser-voirs from which theouter parts of the leafand the stem are attimes supplied. In many cases, noticeably in the cabbage, the epidermisis covered with a waxy coating, which doubtless increasesthe power of the leaf to retain needed moisture, andwhich certainly prevents rain or dew from covering theleaf-surfaces, especially the lower surfaces, so as to hinderthe operation of the stomata. Many common plants, likethe meadow rue and the nasturtium, possess this powerto shed water to such a degree that the under surface ofthe leaf is hardly wet at all when immersed in water.The air-bubbles on such leaves give them a silveryappearance when held under water.. Fig. 121. — Unequal Development of Cuticleby Epidermis-Cells. A, epidermis of Butchers Broom (Buscus); B, epidermis of sunflower; c, cuticle; e, epi-dermis-cells. 158 ilOUNDATIONS OF BOTANY 169. Hairs on Leaves. — Many kinds of leaves are moreor less hairy or downy, as those ot the mullein, the mullein pink, many cinquefoils, and other commonplants. In some instances this hairiness may be a protec-tion against snails or other small leaf-eating animals, butin other cases it seems to be pretty clear that the woolli-ness (so often confined to the under surface) is to lessenthe loss of water through the stomata. The Labradortea is an excellent example of a plant, with a denselywoolly coating on the lower surface of the leaf. Theleaves, too, are partly rolled up (see Fig. 224), with theupper surface outward, so as to give the lower surfacea sort of deeply grooved form, and on the lower surfaceall of the stomata are placed. This plant, like someothers with the sa

Stockbilder mithilfe von Tags suchen

• bookcentury1900
• bookdecade1900
• bookyear1901
• bücherunterlage