The starch formation in potato tuber cells from various sugars was investigated histochemically with reference to the permeability of the cells to these sugars. The availability of sugars for the starch formation in potato tuber was as follows: Glucose and sucrose>maltose>lactose>fructose and galactose>xylose. Mannose and arabinose were ineffective for the starch formation. From the plasmolysis data the permeability of the sugars tested to the tuber cells may be considered to be in the following order: Glucose>sucrose>maltose>lactose>fructose, galactose and mannose>xylose and arabinose.
1) Among various changes of gramineous stigma cells, caused by the attachment of a pollen grain, withering is one of the most conspicuous phenomena. The withering, beginning at the stigma cells to which a pollen grain is attached, gradually spreads to the neighbouring cells. Later the pollinated stigma filament withers entirely all over its length. 2) Pollen grains of the same anther show different behaviours when they fall on stigma cells. These different behaviours of the grains have an intimate relation to the beginning of withering of the stigma cells. In general, the withering begins first at the cells on which a grain bursts, then at the portion where a grain shrinks. Stigma cells on which pollen grains germinate and develop the pollen tubes wither latest. 3) The disappearance of the liquid, oozed out between the pollen and the stigma, has an intimate relation to the occurrence of withering. Some considerations were made on the withering phenomenon.
The monospores of Porphyra tenera were experimented at various developmental stages from immediately after being shed from the Conchocelis-thalli to segmented sporelings. As a result, the following was revealed. (1) At the amoeboid stage the cytolasm is stained with Janus green B reddish purple at a part and blue at the other part. This differentiation is observed before its adhering to the substratum. The spore tends to adhere at the part stained reddish purple. (2) The adhered spore is stained with Janus green B also reddish purple at the base and blue at the apex. After the segmentation, merely the basal cell is stained reddish purple selectively but the apical cells blue with the same dye. (3) The reddish purple coloration of Janus green B at the base seems to be attributed to a reductive property of the basal cytoplasm, and it is predeterminedly differentiated in the amoeboid spore. (4) The basal cytoplasm which occupies the basal cell of the sporeling is acidophilic in nature and is stained selectively with Congo red, eosin, etc., while the apical cytoplasm is rather basophilic and is stained with basic dyes.
1) Using single-node cuttings of young sweet potato stems, elongation of petiole was observed after the treatments with gibberellin (GB, mixture of A1 and A3), indoleacetic acid (IAA) and 2, 3, 5-triiodobenzoic acid (TIBA) as lanolin pastes. 2) GB promoted the elongation of petiole when the leaf blade was present, or was excised but replaced by IAA-paste. 3) TIBA inhibited the growth-promoting effect of GB, as well as of IAA, to appear below the site of its application. 4) Debladed petiole elongated but little even if GB-paste was applied to it. However, when IAA was supplemented later, it elongated more than the one which was supplemented with IAA but had not received GB beforehand. 5) From these results, it is concluded that GB cannot produce its growth-promoting effect unless the tissue contains natural auxin or exogenous IAA.
1.NAA, IBA, vitamin B1, B2, B6, C and nicotinic amide in appropriate concentration promoted the morphogenesis of the isolated internodal cell of Nitella fiexilis. The optimum concentration of these reagents for shooting of the cell was different from the one for rhizoid formation. NAA was more favourable for rhizoid formation than for shooting. 2. Fat soluble substances in low concentrations accelerated the morphogenesis of the cell. Above all, dilute solutions of acetone and of ether were suitable as a culture solution of the cell.