. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. Chapter XIV —161 — The Vacuolar System composed of a jelly or of a coacervate. One is therefore led to believe that the development of the vacuoles described in the pre- ceding pages may possibly be nothing more than an unlimited imbibition of small elements, shaped like granules or filaments, which are in a jellied or coacervate state. This imbibition would involve the transformation of the original gel into a very dilute solution represented by the liquid vacuoles. Chemical nature of the colloidal substance of vacuoles:-
. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. Chapter XIV —161 — The Vacuolar System composed of a jelly or of a coacervate. One is therefore led to believe that the development of the vacuoles described in the pre- ceding pages may possibly be nothing more than an unlimited imbibition of small elements, shaped like granules or filaments, which are in a jellied or coacervate state. This imbibition would involve the transformation of the original gel into a very dilute solution represented by the liquid vacuoles. Chemical nature of the colloidal substance of vacuoles:- The histochemical characteristics of young vacuoles, which we have enumerated to establish a distinction between the chondriosome- shaped vacuoles and the chondriosomes themselves, prove that the. M Fig. 105. — Ricinus root. Meristem fixed by Regaud's method. Black, filamentous or granular chondriosomes (Ch) and vacuoles (V), the latter distinguished by an external hyaline region due to a contraction of their colloidal contents during fixation. colloidal substances of the vacuolar sap have an essentially variable constitution. Vacuoles are present in all plants but there does not exist any substance characteristic of them, as is the case for the chondriosomes. They contain diverse substances having noth- ing in common except their property of fixing vital stains. Vital staining alone reveals differences in coloration between vacuoles. Cresyl blue, for example, changes color in vacuoles which contain metachromatin (majority of fungi, certain algae). It stains them a diffuse red and the enclosed corpuscles are colored dark red. In the cells of phanerogams, the staining of the vacu- oles is extremely variable. Whenever the vacuoles contain phe- nolic compounds, they take a pure blue color with cresyl blue be- cause of their acid pH. This same blue color is sometimes observed when the vacuoles contain lipide substances (phytosterol or phos-. Please note that these images are
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