. Botany for agricultural students . Botany. BREAD MOLD (RHIZOPUS NIGRICANS) 361. upright growth bear the sporangia, while others running over the surface of the substratum produce at certain places a new set of both penetrating and upright hyphae. These runner-like hyphae are called stolons, and serve to spread the mycelium over the substratum. The hyphae which penetrate the substratum are able to change the elements of the substratum into soluble forms and absorb them. The sporangia occur singly on the hyphae and contain numer- ous aerial spores, which when mature are liberated by the breaki
Image details
Contributor:
Central Historic Books / Alamy Stock PhotoImage ID:
PG4B3AFile size:
7.2 MB (175.6 KB Compressed download)Releases:
Model - no | Property - noDo I need a release?Dimensions:
1445 x 1730 px | 24.5 x 29.3 cm | 9.6 x 11.5 inches | 150dpiMore information:
This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.
This image could have imperfections as it’s either historical or reportage.
. Botany for agricultural students . Botany. BREAD MOLD (RHIZOPUS NIGRICANS) 361. upright growth bear the sporangia, while others running over the surface of the substratum produce at certain places a new set of both penetrating and upright hyphae. These runner-like hyphae are called stolons, and serve to spread the mycelium over the substratum. The hyphae which penetrate the substratum are able to change the elements of the substratum into soluble forms and absorb them. The sporangia occur singly on the hyphae and contain numer- ous aerial spores, which when mature are liberated by the breaking of the sporangial wall. The spores are nearly always present, floating about in the air and resting on objects where they happen to fall. It is prob- able that they can live for many years in the dormant state and then germinate when they come in contact with suitable food material. The Bread Mold has no sex organs, but there is a sexual process which reminds one of the sexual process in Spirogyra. Sometimes, as shown in Figure SI 4, tips of hyphae approach each other and finally meet. From each hyphae an end cell is cut off, and these end cells fuse to form heavy walled zygospores. Upon germination the zygospore produces an erect hypha bearing a sporangium of the ordinary type, and the aerial spores developed therein are capable of starting a new series of plants. Conjugation is only occasionally obtained in Rhizopus nigricans unless the cultures are made in a certain way. It has been found that in Rhizopus nigricans there are two kinds of plants, which, although looking just alike, behave differently. They are called strains, one being known as the plus (-|-) and the other as the minus ( —) strain. When either of these occur alone in a culture then no conjugation takes place, but if both are present then Fig. 312. — Methods of repro- duction in the Phylophlhora caclo- rum, which attacks Ginseng. A, sex organs consisting of oogonium (o) and antheridium (a). B, conidi- o