. Botany, with agricultural applications. Botany. FACTORS INFLUENCING PHOTOSYNTHESIS 257 combining the elements of sugar, which is the foundational sub- stance, with nitrogen, sulphur, and phosphorus derived from the mineral salts of the soil. Even if the construction of proteins in leaves does not depend upon light, it is obvious that leaves are well equipped for such work, since they manufac- ture sugar and the water brought up from the soil supplies them with an abundance of mineral salts. Factors Influencing Photosynthesis. â The factors influencing photo- synthesis are light, temper- atur
. Botany, with agricultural applications. Botany. FACTORS INFLUENCING PHOTOSYNTHESIS 257 combining the elements of sugar, which is the foundational sub- stance, with nitrogen, sulphur, and phosphorus derived from the mineral salts of the soil. Even if the construction of proteins in leaves does not depend upon light, it is obvious that leaves are well equipped for such work, since they manufac- ture sugar and the water brought up from the soil supplies them with an abundance of mineral salts. Factors Influencing Photosynthesis. â The factors influencing photo- synthesis are light, temper- ature, moisture, and amount of chlorophyll. That light is absolutely essential for photosynthesis is easily demonstrated by applying the iodine tests to two sets of leaves after one set has been kept in the dark and the other in the light for a few days. Even by shading only a portion of a leaf the necessity of light for photosynthesis can be demonstrated as shown in Figure 235. For photo-. Fig. 235. â A leaf showing the relation of photosynthesis to Kght, as indicated by the amount of starch formed. After cover- ing the area represented by the light band, synthesis sunlight is best, the leaf was left exposed to the sunUght for although some photosyn- a few hours, then removed from the plant thesis will take place in and the iodine test apphed. The area pro- â 1 1- 1-i xu J. I. tected has no starch while the areas exposed artificial light that has a i. j i j ^ ^.i, r , ^ - . ^ , are quite dark, due to the presence of much smtable intensity. It has gtarch. been demonstrated in greenhouses that some plants, at least, carry on photosynthesis at night if the proper kind of electric light is provided. For many plants the direct rays of the sun are too intense, in which case photosynthesis is most active in strong diffuse light. It is partly for this reason that Pineapples, Tobacco, Potatoes, Cotton,. Please note that these images are extracted from scanned page images that may
Size: 1379px × 1811px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1920
