. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. SYNTHESIS OF FOOD WITHOUT LIGHT 153 While the synthesis of nitrogenous foods presumably can take place in any living cell there are reasons for believing that most of this work is done in the leaf. Mature leaves at the height of their activity contain large amounts of the amide as- paragin that hardly can be accounted for except by the theory that they are manufactured there. Although there is more asparagin present in leaves in the evening than in the morning this
. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. SYNTHESIS OF FOOD WITHOUT LIGHT 153 While the synthesis of nitrogenous foods presumably can take place in any living cell there are reasons for believing that most of this work is done in the leaf. Mature leaves at the height of their activity contain large amounts of the amide as- paragin that hardly can be accounted for except by the theory that they are manufactured there. Although there is more asparagin present in leaves in the evening than in the morning this does not necessarily imply that light is required for its pro- duction, for both asparagin and carbohydrates would diffuse out of the leaf during the night, and the produc- tion of asparagin could not be kept up for lack of carbo- hydrates which are needed in its manufacture, and which we knOw can only be made in the light. Although approximately four-fifths of the atmos- phere is nitrogen the vast majority of plants are un- able to use it in its un- combined form for food construction, and for this purpose it must be taken, in the case of green plants, mostly in the form of some nitrate, such as calcium or potassium nitrate. The case is different with saprophytic plants, such as the toadstools and their kind, moulds, and many forms of bacteria, for these plants can appropriate for food various nitrogen compounds in the excreta and dead bodies of other plants and animals. Parasitic plants, such as the rusts, mildews, blights and smuts, and those of higher order, such as Cuscuta, appropriate the food of the plants upon which they are parasitic. Although the green plants and plants in general are unable to appropriate the free nitrogen of the air, there are a few forms of bacteria which have this power, such as Clostridium Pasteur-. FiG. 86.—Cross section, A, and surface view, Bt of a leaf of common moss, showing chloroplasts, Please note that these images are extracted fr
Size: 1581px × 1581px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectplantanatomy, bookyea
