Students' handbook to accompany Plants and their uses . he roots, the stem, and the leaves, into the interior of theleaf. From the leaf some of this water is evaporated intothe air. Part of the water in the leaf, instead of being evaporatedinto the air, is used in the construction of plant food by meansof a process which is of very great importance to all livingthings. Carbon dioxide from the air enters the leaf throughits surface. The leaf is green because of the presence of a 14 INTRODUCTION TO BOTANY coloring substance known as chlorophyll. When the sun shinesupon the leaf, the chlorophyll
Students' handbook to accompany Plants and their uses . he roots, the stem, and the leaves, into the interior of theleaf. From the leaf some of this water is evaporated intothe air. Part of the water in the leaf, instead of being evaporatedinto the air, is used in the construction of plant food by meansof a process which is of very great importance to all livingthings. Carbon dioxide from the air enters the leaf throughits surface. The leaf is green because of the presence of a 14 INTRODUCTION TO BOTANY coloring substance known as chlorophyll. When the sun shinesupon the leaf, the chlorophyll absorbs energy from the sunsrays. This energy serves to decompose the water and carbondioxide. The products of this decomposition immediatelyreunite, but into new substances, which, after several chemi-cal changes, may become sugar or starch. Sugar and starchmay be used as food by the leaf, or be carried to other partsof the plant and used, or be made into more complex foods,as oils or protein foods. It is from foods that plants as well as animals de-. > Stamen> Pistil FKJ. (J. Diagrams of two flowers A, entire dower; /,, flower with part of the floralstructures removed that makes ac-tivity, growth,and life itselfpossible. Since wateiand carbon di-oxide, the sub-stances fromwhich a greenplant thus man-ufactures food,are substances that are not ordinarily regarded as foods for other living things,this process is far-reaching in its significance. The storage ofsurplus plant food in seeds (fig. 12), roots, stems, and leavesis also most significant, since our food and many of ourindustries depend upon this surplus material. 12. The flower. In addition to the roots, stems, and leaves,Mowers are often conspicuous pails of plants. They are thestructures liy means of which seeds are produced. In someplants but one kind of flower is produced (fig. 9); in otherstwo kinds are formed digs. 10 and 11). In such a flower asthat shown in figure .» the outermost and lowest floral partsfo
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Keywords: ., bookcentury1900, bookcollection, bookdecade191, booksubjectbotany
