The excised stem-tips of the germinating tubers of Stachys sieboldii Miq. were cultivated under the laboratory condition. As the room temperature decreased, the formation of tubercles on the tips of the explanted stems was observed. The excised tips of the rhizome at its different stages of development, when cultured in vitro, demonstrated variations in tuber formation. When the excised tips were taken from the rhizomes which had just emerged from the base of the aerial shoots, they usually failed to grow. However, existence of normal growth was observed in the cultured excised tips of the rhizomes that had become elongated at which time flowering occurred on the aerial shoot. The tips became swollen as the environmental temperature decreased. In early September, as the process of underground tuberization initiated, cultures taken from the nontuberized tips again grew poorly and usually failed to form tubercles.

The present paper deals with the effect of osmotic value of the medium on the growth of the young sunflower embryos grown in vitro. Based upon the results of a series of experiments carried out during 1963 the following conclusions are reached: 1. The sunflower embryos grown in vitro require different concentrations of sucrose, varying with the age at which the embryos are excised. Generally speaking, the optimum concentration of sucrose for the embryos 1,000–1,100μ in length is about 17.5%, for 2,000–2,500 μ, about 16% and for 5,000–5,500 μ, about 12.5%. 2. The sucrose may be partially replaced by sodium chloride (0.2%–0.4%) or mannitol (1.125%–5.5%) as an osmotically active substance, but 0.8% sodium chloride is apparently toxic to the young embryos. 3. Embryos cultured in hypotonic medium usually germinate precociously, those in approximately isotonic medium continue their embryonic growth, while those in hypertonic medium become more or less checked in their growth.

With the method of comparative physiology, tomato plants (Lycopersicon esculentum Mill), chlorella (Chlorella pyrenoidosa Chick), callus tissue (Parthenocissus tricuspidata Pench), and black Aspergilli (Aspergillus niger von Tieghem A.S. 3.316 and Aspergillus usamii Sakaguchi A.S. 3.758) were used as experimental materials to study their zinc requirements in relation to light. The results showed that the requirement of zinc of tomato plants was increased with the increase of light intensity. The growth of chlorella in light under mixotrophic condition required more zinc than those grown in the dark under heterotrophic condition. The growth of callus tissues required slightly more zinc under light than in the dark. However, the requirement of zinc in black Aspergilli was not affected by light or darkness. Therefore the physiological role of zinc in autotrophic plants can be considered as related to light and that in heterotrophic plants is not. On the other words, two kinds of physiological functions of zinc in plants could exist, one is related to light and the other is not. The former might be in connection with photosynthesis and the later might be related to the constitution of enzyme or to the synthesis of auxin.

The effects of light intensity, mineral nutrients and seasonal climatic changes on the alkaloid contents of Rauvolfia yunnanensis Tsiang were studied and the experimental results were summarized as follows: The alkaloid contents of Rauvolfia roots increased with the light intensity decreased, and a maximum was reached at about 28% of the normal day light. The supply of the mineral nutrients of P, K especially N would raise the root production and alkaloid contents respectively. Determinations were carried out about the variations of alkaloid contents of the roots, stems and leaves on the samples collected every month of the year from both the wild and the cultivated Rauvolfia. The alkaloid contents in the roots of both wild and cultivated Rauvolfia appeared with only one high peak-August to September (end of the raining season), and a period with low contents appeared from March to May (dry season). The alkaloid contents in stems appeared with two high peaks, one was in coincidence with that of the roots, the other appeared between March and May (dry season) just as the period with low alkaloid contents in root. The alkaloid contents of leaves of wild Rauvolfia appeared with two high peaks, both were the same as those of the stems, but in the cultivated Rauvolfia, only one peak with high contents from July to August (raining season) was observed.

The spore morphology of 32 species of Vittaria Smith has been described. Spores are ellipsoidal or long ellipsoidal in polar view, and kidney-shaped in equatorial view, (18.2–65) × (39–110.5) × (19.5–52)μ in size, monolete, without perine. The stratification of exine which is generally 1.9–2.6 μ in thickness is distinct or indistinct. When it is distinct, the sexine is thicker than the nexine. The exine is generally orna- mented with indistinct granulose or vague sculpture, and with small verrucae in three species. In some species, there is a striate texture on the surface of the exine. As far as it goes, it is a very interesting phenomenon that has not been mentioned elsewhere in the literature of palynology. According to the references, the spores are trilete in a few species of this genus. But it is only monolete in our investigated meterial. Because the gross-morphology of plant in these genera of Vittariaceae is very similar to one anther, we raise the quastion whether the few species which have trilete spores really belong to this genus or to the other genus of Vittariaceae which have trilete, it may be further considered. On the basis of the spore types, Vittariaceae (E. B. Copeland, 1948) may be divided into two groups the one belongs to monolete spore type, and the other to trilete spore type. Based on morphology and anatomy of the plant, R. C. Ching (1940) separated out some genera which have trilete from Vittariaceae to establish a new family– Antrophyaceae, it is valuable to further exploration.

Detailed studies on the process of double fertilization in rice were conducted in the present work. The results are summarized as follows: 1. In the embryosac 30 minutes after anthesis, the pollen tube has already reached the micropyle in every specimen. In some cases, it has even entered further into the embryosac and discharged its contents, including the two male gametes. 2. 1½ hours after anthesis, the male gamete enters into the egg cell. As soon as it comes in contact with the egg nucleus, it increases in size. 2 hours after anthesis, the male nucleus is found inside the female one. A male nucleolus is now clearly discernible. 3. The male nucleolus is gradually growing until it reaches the size of the female one, and then the fusion of the two takes place. The fusion is generally completed and the zygote is formed 7 hours after anthesis. 4. The first mitotic division of the zygote occurs 9 hours after anthesis. 5. The fusion of the male gamete and the polar nucleus proceeds in a similar way as that of the male and female gametes, but it takes a much shorter time usually being completed within 3 hours after anthesis. 6. The male gamete enters into one of the polar nuclei and reveals its nucleolus which increases rapidly in size and then unites with that of the polar nucleus. As soon as the union is completed, the nuclear membrane between the closely contacted parts of the two polar nuclei disappears and the primary endosperm nucleus is formed. 7. The first mitotic division of the primary endosperm nucleus begins right after its formation. 8. With the fusion of the male and female gametes and the development of the zygote, the mitochondria in the cytoplasm surrounding the nucleus increase in size and number. However, in the central cytoplasm about the polar nuclei they show no notice- able change during the fertilization process. 9. Based on the facts that in the embryosac a secondary pollen tube is often seen in every stage of the fertilization process and that additional nucleoli are also observed sometimes in the egg nucleus, the authors believe that polyspermy most probably exists in rice plants, and that this may be one of the causes of polyploid plants often found in rice field as reported by several authors.

1. By means of cell separation, pectinase cell separation and routine paraffin method, we studied the cell types of leaves of wheat, Nongda 183 and several other varieties. 2. We observed in all the cell types, the presence of mitochondria, spherosomes, plastids or chloroplasts, though the morphology and distribution of these organelles vary to a certain extent they do not interfere with the recognition of these cell types. 3. The plastids and mitochondria of the long cells in the epidermis are of various forms. Most of these organelles are distributed in the portion of the cell away from the leaf surface. 4. In each one of the guard cells, there are many morphologically stable, pale-colored but shining plastids. They are peculiar to the guard cells and cannot be found in any other cell types. 5. The bulliform cells are in ball and socket connection with the mesophyll cells underneath, while the organelles of bulliform cells are concentrated at the surface of the socket. 6. The number of the chloroplasts in the mesophyll cells is not quite constant. From the external morphology and the distribution of the chloroplasts, the mesophyll cells can be divided into, at least, two morphological types. 7. The outer bundle sheath cell is divided into chloroplast-prominent and mitochondria-prominent halves. This peculiar structure of the cell reveals the function and the transitional position it occupies in the leaf. This is a good example of unity of function and structure. 8. The inner bundle sheath cells can be recognized readily by the presence of prominent pits in the walls. The protoplasmic streaming of these cells is very active. Plastids and mitochondria can be seen clearly. 9. The importance of the cell types of these specialized cells and their variously shaped and distributed organelles is discussed.