Studies on the Development of the Ventilating System in Relation to the Tolerance against Excess-Moisture Injury in Various Crops. : VII. Comparative studies on the ventilating pressure in lowland and upland rice plants growing under flooded and under water economized conditions. : VIII. On the ventilating system and the ventilating psessure in various plants growing on lowland and on upland.

Abstract

Further studies were made on the ventilating system in various plants in relation to the ventilating pressure, the results being summarized as follows: 1) A highly developed ventilating system was observed in various lowland plants, wherever they might be grown, They exhibited a lower ventilating pressure, varying almost in accordance with the metabolic activity of their roots. 2) On the contrary. feebly developed ventilating systems were observed in upland plants, as far as they were growing under dry conditions. They could accomodate themselves to over-moist haditats, by means of reconstructing the ventilating system likely enough to make it possible for their roots to receive considerable amounts of oxygen from their tops. Considerable degrees of reformaticn in the ventilating system and renewal of the root system were observed when they met with over-moist conditions. 3) Referring to the POISEUILLE's and FICK's laws, a theoretical explanation of the relation between the significance of the ventilating pressure and the gaseous diffusion from the top to the root was presented. Explanation of figures The dotted portions in all the figures refer to the intercellular spaces containing much air or the tissue having those spaces. The abbreviations are as follows : Ca, cavity; co, cortex or hypodermis; en, endodermis; ep, epidermis; ha, hair; ly, lysigenic space; pi, pith; rh, root hair; rv, reinforced vascular bundle; sv, separated vascular bundle; sz, sizogenic space; va, vascular bundle. Rice plant (common to the lowland and upland rice pldnts). Fig. 1. Internode of the peduncle. Fig. 2. The 1st internode (the uppermost). Fig. 3. The 2nd internode. Fig. 4. The 3rd internode. Fig. 5. The 4th internode (the lowest elongated one). Fig. 6. Not elongated internode in the 5th order. Such an internode is a component of the so-called tillering portion, totaling about 12 internodes in succession. Barn-yard grass and other grasses. Fig. 7. Internode of the peduncle. Fig. 8. The 2nd internode. Fig. 9. The 4th internode. Fig. 10. The 6th internode (the lowest elongated one). Fig. 11. The stem of Ranunculus sceleratus. Fig. 12. The stem of Veronica Anagallis. Corn plant growing on upland (12 leaf-stage). Fig. 13. Middle portion of the 4th green leaf-sheath. Fig. 14. The 4th node to which the 4th green leaf-sheath is attached. Fig. 15. The 6th internode. Fig. 16. Root zone with a crown root. Fig. 17. Basal portion of a crown root. Fig. 18. Middle portion of the crown root. Corn plant kept flooded (12 leaf-stage). Fig. 19. Middle portion of the 4th green leaf-sheath. Fig. 20. The 4th node to which the 4th green leaf-sheath is attached. Fig. 21. The 6th internode. Fig. 22. Root zone with a crown root. Fig. 23. Basal portion of a crown root. Fig. 24. Middle portion of the crown root.