Studies on the Maternal Inheritance of Plastid Characters ...

192 [Cytologia, 1

Studies on the Maternal Inheritance of Plastid Characters in Hosta japonica ASt1ERS. et

GRAM. f. all omarginata MAK. and its Derivatives*

By K. YAsul

Tokyo Imperial University

(With Plates 13 and 14)

CORRENS was the first to find a case of maternal inheritance in plants, in a strain of Mirabilis Jalapa, and explained it as a plasmatic and not a nuclear inheritance. BAUR (1911), who observed a similar

phenomenon in Antirrhinum majus albomaculatum, proposed a working hypothesis that the character is localized in cytoplasm, and not in

plastids. GREGORY (1915), describing the case of maternal inheritance in yellow and variegated plants of Primula sinensis, however, did not support BAUR's hypothesis, and in view of the fact of the presence of normal and yellow chloroplasts side by side in one and the same cell in very young leaves of the plant, assumed that the abnormality is localized in the chloroplasts. But he could not find this simultaneous

presence of different kinds of chloroplasts in mature plants. WINCE (1919), on his paper on non-Mendelian inheritance supported GREGORY'S view. RANDOLPH (1922) studied the development of plastids in the cell of striped maize, which inherited the characters maternally, and observed the cells which contain plastids varying greatly both in size and intensity of green pigment, in the border line between the green and yellow tissues. There are a few other observations on the presence of two kinds of plastids in one and the same cell, but no clear relation of plastids and maternal inheritance was determined. CHITTENDEN

(1925), reviewing on 'vegetative segregations,' is inclined to the hypothesis of plastids inheritance.

* Contributions to Cytology and Genetics from the Departments of Plant-Mor

phology and of Genetics, Botanical Institute, Faculty of Science, Tokyo Imperial University. No. 87.

1929] Studies on the Maternal Inheritance of Plastid Characters 193

The writer's cytological and genetical studies on the variegated leaves of Hosta japonica ASHERS. et GRAEBN., f. albomarginata MAKINO (Suzigibosi) and some clones derived from this form seem to give cytological evidences, as will be seen below , to account for the maternal inheritance of leaf colours of this plant .

Here we must note, however, that STRASBURGER (1877) described the apogamy and polyembryony in Funkia ovata (Hosta japonica ASHERS. et GRAEBN., f. coerulea MAKINO ?), an allied plant to the writer's material. To determine whether such is also the case with the

present material or not, the writer made some observations on the process of embryo formation, because if this were the case as in Funkia ovata, the phenomenon does not belong to the maternal inheritance in its limited sense of the words.

Material and Methods

In 1922 and 1923, over one thousand seeds of Hosta japonica ASHERS. et GRAEBN., f. albomarginata MAKINO were sown by the writer. Almost all of the seedlings from them were pure green, except some albinos which died off soon after three or four leaves had appeared , and a few variegated individuals which survived.

From the latter and their offsprings raised by selfing, several

plants, which were different from each other in colour of leaves and other characters, were derived ; and they served as materials for the

present studies.Fresh as well as fixed materials were used for cytological studies.

For fixing FLEMMING's (Bonn modification), BENDA'S, MERKEL's, and CARNOY'S solutions were used, and for staining sections of fixed material HEIDENHAIN'S iron-alum haematoxylin was used, iron aceto-carmine method being adopted for the study of fresh pollen mother cells.

To avoid the destruction of plastids in the cell, which usually takes place by sectioning of fresh material, the mesophyll parenchyma of fresh leaves was examined from the surface of leaves, and photo

graphed through the epidermis. For this purpose the air in the intercellular spaces in the tissue was replaced by water, by means of a vacuum pump. By such treatment no change in the cell was observed, as compared with that of non-treated material, as far as the morphological feature of plastids is concerned.

194 K. YASUX [Cytologia, 1

Observations

A. Parent Plant

The parent plant, Hosta japonica ASHERS. et GRAEBN., f. albomarginata MAKINO (Text-fig. 1), a garden plant in Japan known by the

name 'Suzigibosi,' has generally green leaves with yellowish white margins (Pl. 13, Fig. 1, a), but in rare cases the white tissue extends inward up to near the midrib as is seen in Pl. 13, Fig. 1, b.

Text-fig. 1. A photograph of Hosta japonica ASHERS. et GRAEBN.f. albomarginata MAKINO. 1/4 nat. size.

Sometimes bud variations having pure green leaves only appeared from the parent plant.

All guard cells of stomata of the 'albomarginata' plant had normal chloroplasts.

The following different kinds of cells with regard to theirr chloro

plast-contents were observed in the marginal tissue of the leaves:

1) Cells containing no plastids.


2) Cells containing colourless plastids as is shown in Pl . 14, Figs. 1 and 2. Fig. 2 shows a palisade cell drawn after a -cell in Fig . 1, a microphoto of a piece of colourless tissue of the leaf , the photograph h

aving been taken after the tissue was treated with a potassium iodideiodine solution. The small spots show the colourless plastids which have vacuoles. n shows the nucleus in the cell . The degree of vacuolate condition in them is various. Such plastids in the mesophyll have

probably no power of CO2 assimilation, so far as is shown by the fact that they never contain assimilation-starch.

3) Cells (Pl. 14, Figs. 5 a and 6 a) containing pale greenish yellow

plastids, which generally have one or two small deeper coloured green spots, as is shown in PI. 13, Fig. 3, a. Plastids in a cell are not much different in size from one another. The pale greenish yellow plastids have the capacity of CO2 assimilation, as is seen by the demonstration of starch grains in them by iodine test.

4) Cells containing green plastids, in addition to the pale greenish

yellow plastids as in 3). This mixed state is shown in P1. 14, Fig. 5, b. To present the mixed condition more clearly, Fig. 6, b was drawn by the aid of a camera lucida. The plastids in black in Fig. 6, b show green ones, and the shaded ones yellow. The ratio of the number of the two kinds of plastids in a cell varies in different cells; in the extreme case there are found cells containing only one grain of one kind among numerous grains of the other kind.

5) Cells containing green plastids mixed with colourless ones, as is shown in Pl. 14, Figs. 3 and 4. Three black grains in Fig. 3 show

green plastids, while light coloured grains vacuolate colourless plastids. The sizes of plastids differ in different cells, sometimes green plastids being considerably larger. The ratio of the number of two kinds of

plastids in a cell varies in different cells.6) Cells containing three kinds of plastids, namely green, yellow

and colourless ones simultaneously, their sizes being variable. Quite small, but seemingly perfect green grains mixed with the larger green ones were observed in some cells.

7) Pl. 14, Fig. 7 shows a cell with green chloroplasts only. This was drawn from the cell presented in Fig. 8 as a microphoto.

An ordinary green cell in green tissue of the albonnai ginata leaf resembles the cell of 7). The green plastids in pure green tissue are

generally of the same size as one another.Transitions from the ordinary green tissue to yellow or white

tissue are generally abrupt as is shown in Pl. 14, Fig. 9 which is a

196 K. YASUI [Cytologia, 1

microphoto; but sometimes cells or tissues containing two or three

different kinds of plastids side by side are observed in a transitional

region.

There were also observed some small patches of colourless cells

imbeded in green or yellow tissue, as are shown,in Text-fig. 2, A and B.

Text-fig. 2. A, microphoto of a piece of yellow tissue which has a colourless

cell patch in the center. •~200; B, microphoto of a green tissue in which

two colourless cell patches are seen. •~180.

Also in the transition cells between these colourless patches and

the surrounding green tissue, there were observed cells which contained

two kinds of plastids as is shown in Text-fig. 3.

Text-fig. 3. A small white patch like Fig . 2, B, surrounded by green tissue.

•~ 400.


Likewise in the colourless or yellow tissue there were observed

isolated green cells, patches of green cells and cells with both green and colourless or yellow plastids.

B. Offsprings

a) Albo-marginata

Some offsprings from the above mentioned parent plants are similar with regard to the chlorophyll characters to the parent plants. Plastids in the tissue are also similar to those in parent plants. There were observed a few colourless cell patches in subepidermal tissue of a floral shoot; and in the deeper cortical tissue, cells which have a smaller number of green plastids mixed with ordinary green cells.

Cells in the pith had smaller number of green plastids.The 'separation' of .the chlorophyll characters in seedlings raised

from seeds of selfed plants is shown in table 1.

Table 1

Ped.=Pedigree. Varieg.=Variegated.

14


b) Green plant

Green offsprings from the albomarginata parents and green bud variations kept their character faithfully during the last five years. The number of the seedlings from seeds of such selfed plants is shown in table 2.

Table 2

c) Albo-chloro-variegataLeaves are green with white and yellow stripes in spring as is

shown in Pl. 13, Fig. 8, b, though the white part is not very prominent in external appearance; but in summer those yellow parts become greenish yellow or pale green as shown in Pl. 13, Fig. 8, a. Plastids in the tissue of white and yellow parts are similar to those of the parent plant.

The isolated cells containing green and yellow plastids together and those containing green and colourless plastids together (Pl. 13, Fig. 8, c) were observed along the border lines between the two kinds of tissues correspondingly of different colours. As patches, such cells with mixed kinds of plastids occuur also in tissue other than along the borderlines.

In these plants the colourless plastids were larger than green ones and prominently vacuolated.


The albo-chloro-variegata plants, A, B, C, in table 3 produced green bud-variations every year. The 'separation' of the chlorophyll characters in seedlings raised from selfed flowers of both green and variegated branches are shown in table 3.

Table 3

The albino and yellow seedlings are not viable, both perishing as soon as they use

up the nutrient stored in the endosperm.

d) Medio-albinata

We have two stocks (Peds. 70/6/13/7 and 70/20) having this character. Their leaves are white with green margin as exemplified in Pl. 13, Fig. 2. When medio-albinata leaf is quite young the white part is somewhat yellowish, but afterwards as it grows it becomes white. They produced bud variations with albomarginata leaves in Ped. 70/6/13/7 and those with green leaves in Ped. 70/20. The plastids in the white part were large and colourless like the colourless one in P1. 14, Figs. 1 and 2, except those in quite young leaves in which the plastids were somewhat yellowish. Vacuolate condition in the colourless plastids was very prominent in this case, sometimes leaving a very small amount of plastid plasm. The transition from colourless to green tissue is generally abrupt, there being only few intermediate cells having two kinds of plastids. The green spots in colourless tissue were not found.

14*


The length of floral shoots of medio-albinata is considerably shorter

than those of albomarginata and of green bud variation, the white floral

Text-fig. 4. A medio-albinata plant

(Ped. No. 70/20) to the left, with a

green bud-variation, to the right. •~ 1/4

shoot of medio-albinata being as short as even less than two thirds of the green shoot (Text-fig. 4.)

Text-fig. 5 shows two kinds of floral shoots, white and green, sprouting from one and the same stock, and both bearing capsules.

(b) is the shoot of medio-albinata, and (a) that of a green bud variation. In these two photographs, the difference of the colour of capsules is clear, one being white, except for a narrow stripe along the suture line of capsules. In the floral shoot of medio-albinata, almost all subepidermal cells have no green plastids, but the deeper cortical tissue has a few green spots which are somewhat triangular in cross sections, the base of the triangle being turned toward the endodermal side and the apex toward the epiaermis. Green tissue in leaves is continu ous with that of the cortex of the stem.

The 'separation' of chloro

phyll characters in seedlings raised from the selfed flower of the Ped. 70/6/13/7 is shown in table 4.

From this table we can see that the medio-albinata plant does

not give any green offsprings when selfed.Medio-albinata shoots of a plant of Ped. 70/20 came to flower and

the pollen grains were viable; and the flowers of green shoots of the

plant and of other strains pollinated by the latter beared seeds, while the selfed flowers of the medio-albinata shoots as well as the flowers crossed with the pollens of other strains fell off 2 or 3 days after the

pollination.


e) Medio-chlorinata, two plants: Ped. 70/6/19/3 and Ped . 70/19.

Text-fig. 5. Two floral shoots bearing

capsules.

a, green; b, white. •~4/5

The plant closely resembles medio-albinata not only in leaf colour, but also in general features. The median longitudinal

parts of spring leaves are yellow as is shown in Pl. 13, Fig. 3, while those of summer leaves are greenish yellow. In contrast to this there has been observed no such climatic difference in medioalbinata plants. The plastids in the mesophyll cell in the median

part of the leaf are small and pale greenish yellow (Pl. 13, Fig. 3, a, left half; thus the cell containing them belongs to the type 3) of the cell in the parent plant. The transition from the yellow or pale greenish yellow part to green part is sometimes abrupt as in

the present figure, but in other cases the border line between green

and yellow tissues consists of cells containing green and yellow

Table 4


Table 5

All pure yellowish white plants and a yellowish white plant marked with *which

had one leaf with a slender green stripe, perished after a few leaves appeared . The

plant marked with **had white variegated leaves and grew healthy.

plastids together as shown in Pl. 13, Fig. 3, b. The latter kind of cells was also observed frequently as isolated spots in yellow tissue, giving the impression of green stains on the older leaves.

One plant (70/6/19/3) gave green bud variations and the other (70/19) an albo-striata variation.

Capsules on the medio-chlorinata branch were almost white except for slender green lines along the suture lines of capsules as in the medio-albinata.

The mode of 'separation' of chlorophyll characters in seedlings raised from selfed plants is shown in table 5.

f) Chloro-variegata

This plant is easily distinguished from others. The leaves, as shown in Pl. 13, Fig. 7, are irregularly yellow-striped green, the yellow colour being deeper than that of medio-chlorinata plants, and hardly showing such a climatic change as observed in the latter.

The deeper yellow colour is due to the larger and deeper coloured

yellow plastids which are shown in Pl. 13, Fig. 7, a and b. Fig. 7, a


shows abrupt transition from green (to the left) to yellow (to the right) tissue in spongy parenchyma, and Fig. 7, b some cells in palisade

parenchyma along the boundary line between green and yellow tissues. In the latter we can see yellow plastids mixed with green ones.

On the floral axis there are yellow stripes of different breadths and such stripes became prominent on the surface of capsules as they grew, but finally stripes became obscure again in ripe fruits, due to the discolouration of the plastids.

It is interesting to observe in this plant that the surface colour of capsules determines the leaf colour of seedlings raised from the seeds formed in them. This relation is shown in table 6.

Table 6

Plants marked with * and **, perished after 2 or 3 leaves developed. The plant marked with *** is an exception which developed white variegated leaves.


g) Chloro-striata and Albo-striata

There were three plants which had leaves with yellowish white stripes. Plastids in the cells of the yellowish white part were almost colourless in one plant (70/18), and somewhat yellowish in the other two. The transition from green to white tissue was generally abrupt, but in some part there were observed cells with mixed plastids.

The leaf colour of seedlings raised by self-pollination is shown in table 7.

Table 7

Albino and yellowish white seedlings were not viable.

h) Albo-maculata

Pl. 13, Fig. 6, a shows one of young leaves of the plant . The

narrow leaf margin was green and the broad median part was pale

green. But, when such a leaf gets old, the median part becomes white

with diffuse green stains, as is shown in Pl. 13, Fig . 6, b. P1. 14, Fig. 11

is a microphoto of a part of palisade tissue from the leaf portion

marked with •~ in Pl. 13, Fig. 6, a. Many cells in the mesophyll had

small pale greenish plastids only, while some cells contained plastids

similar to the latter as well as small green plastids side by side, and a

few others contained some colourless plastids. In the process of

development of the leaf the pale greenish yellow plastids became

colourless as are shown in the left half of Pl. 14, Fig. 12 . In the cells

which contained green plastids mixed with pale yellow ones or green

ones only, the green plastids developed normally, or even larger than

normal ones as are shown in Pl. 14, Fig. 14 and Fig. 13 , b and a.


Owing to these changes in the cells, the median part of the leaf

became white, leaving some green stains due to the presence of cells with mixed and green plastids in the mesophyll tissue . Pl. 14, Fig. 12 shows the abrupt transition between the marginal green and median white tissue.

In some leaves, such white portion of blade did not develop , so much as in the above mentioned leaf, but white spots in the green

portion became larger as the leaf grew old, and it gave the impression that the number of spots had increased. In the latter case the colour

of such a leaf, as is shown in P1. 13, Fig. 5, did not fade so much as in

the first example; and in some leaves the green colour became even deeper as in Pl. 13, Fig. 6, c. The latter leaf having no green margin has been derived as a bud variation; this leaf became deeper green as it

matured, proceeding from the top toward the base, leaving a light

coloured portion at the base.The state of 'separation' of chlorophyll characters in seedlings

from the selfed plant is shown in table 8.

Table 8

Yellow seedlings and also nearly all of albo-maculata died after a few leaves

appeared.

i) Plant with shrunken leaves

There appeared one plant with shrunken leaves like one shown in P1.13, Fig. 9. The spongy parenchyma is well developed in the underside of the leaf, but cells in a part of palisade parenchyma and in the upper part of spongy parenchyma did not develop well and had no

plastid, so that such tissue is white and results in shrunken leaves of abnormal appearance as in the figure.

In this plant flowers did not fully develop, and consequently have

given no fruit during these two years.


C. Embryo Formation

In the parent plants and their offsprings, a-h, pollen and embryosac formations were normal. Castrated or not-pollinated flowers

dropped off in two or three days after their opening, thus showing the

need of pollination for the development of the fruit. Normal development of sperm-nuclei in the pollen tube which penetrated into the ovule was observed. Though sperm nucleus was not traced in the egg cell,

the penetration of the contents of the pollen tubee into the embryo-sac

and the two cell stage of proembryo were observed. Such proembryo seems to develop to the normal embryo and there is no trace of protru

sion of nucellar embryo which was found in the ovule of Funkia ovata by STRASBURGER. The embryo was found in the normal position, and no polyembryony was observed among several thousand seeds which were investigated by the writer.

D. Crossing Experiments

Table 9 shows the colour of leaves due to the plastids pigments and purple spots on the leaf base of F, plants raised by cross pollination between some of the plants a-h.

In the table 10, the results of self-pollination, with reference to those characters mentioned above of the parent plants are given.

Comparing these two tables we notice on the one hand that the state of 'separations' of the plastid characters in question among individuals of F1 generation shows that they did not receive any influence from their male parents, but inherited the character of their female parent only; and on the other hand that the purple spots at the leaf base were inherited from the male as well as the female parents.

There was made in 1924 one crossing between a green female derived from albomarginata and a medio-albinata male. The F1 generation was all green, and F2 generation containing 119 plants were all green except one which had a slender white stripe on one of the seven leaves. This result shows also that the character does not indicate Mendelian inheritance. The explanation of the appearance of a striped leaf will be given on a later page.

Discussion

The results of investigations on embryosac formation and of

genetic studies on purple spots on the leaf base show that the normal


fertilization occurs in these plants, and unlike the case of Funkia ovata studied by STRASBURGER, no apogamy takes place here. Consequently we can consider that the chlorophyll characters above referred to are inherited through either the male or female gametic cell or through both.

The results of the hybridization experiments show, however, that the chlorophyll character in question of the present Hosta and their derivatives show non-Mendelian inheritance, being transmitted maternally, so that the mode of inheritance is different from that of `Kosuzigibosi' (Hosta sp.) reported by TERASAWA (1923), in which he maintains that the chlorophyll characters show no maternal inheritance.

The variegation of leaf colours in floral axis which extends down to the stem is due to the distributions of different kinds of chloroplasts, chiefly in mesophyll and cortical cells.

In the internode of the stem covered with leaf base, distribution of chloroplasts could not be determined, owing to the non-development of the chlorophyll pigment, while roots exposed to sun light, as is clearly shown in floral shoot of medio-albinata plant, present different reactions to the light according to their different positions on the stem; namely, roots growing immediately below the white part of the leaf base were white, while those growing below the green margin of the leaf base green. The latter facts indicates that the mode of distribution of different chloroplasts in leaf bases is kept through the corresponding internode of the stem also. Consequently we may provisionally assume that the different chlorophyll characters here concerned are due to the different distributions of the various kinds of cells with regard to their chlorophyll contents, in the growing point of the stem.

Though GREGORY did not recognize two different kinds of plastids side by side in the same cell in mature plants, he observed them in young plants and held the view that the abnormality is localized in the chloroplasts themselves. WINGE (1919) supports GREGORY's view for yellow and variegated Primula, Mirabilis Jarapa albomaculata, and Antirrhinum majus albomaculata, but not for his Humulus japonicus var. albomaculata which according to him shows cytoplasmic inheritance. RANDOLPH (1922) observed in the tissue of border lines between the green and yellow stripes in leaves of a certain strain of maize, which transmits the chlorophyll character maternally, cells containing plastids, which vary greatly both in size and intensity of green pigment. Describing the development of plastids in different stages of development of the leaf, however, he came to the conclusion that the view

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that his case is not that of plastid inheritance, and that GREGORY'S mixed plastids is nothing but a characteristic of cells of young leaves.

Some authors described the effect of yellow tissue upon the neighbouring green tissue and vice versa; e.g. ANDERSON (1923) having described the presence of intermediate cells the border line between the green and yellow tissues in variegated prothallium, considered the

phenomenon as the result of the influence of green cells upon the yellow ones, and took her case for a plastid inheritance, CHITTENDEN (1925) observes in his review of the accounts of above mentioned authors: "This influence of one plastid type upon another renders it impossible

that any actual mixture will ever be observable in the same cell. In other words the appearance of the plastid complement any cell would be determined perhaps by the nature of the majority of the plastids, or by the dominance of one plastid type."

Such an influence of one kind of plastid upon the other could not be observed in the cells of writer's albomarginata plants and its derivatives. The presence of the pure abrupt transitions between different kinds of tissues and of ordinary green cells among colourless or mixed tissue as is shown in Pl. 14, Fig. 13, b shows that there is no influence of different kinds of plastids between each other.

As mentioned before, there were observed cells containing two or more kinds of plastids in the mature leaves of those variegated plants without exception. The different plastids in the same cell are not distinguishable in their younger leuco-stages; but when they reach a certain developmental stage their colours become prominent and the

green chloroplasts become larger and deeper green than the others which develop into yellow and colourless plastids. The writer did not observe in mature cells so many intermediate forms of plastids as RANDOLPH observed in maize; but in very few cases there were observed extremely small green plastids in one and the same cell mixed with the larger green plastids and other kinds of them.

The climatic influence for the development of chlorophyll pigments in yellow cells (though the writer has not yet able to determine whether heat energy or light itself is the more effective) was observed as already mentioned on page 205, but the colourless plastids did not show any tendency to develop pigment by the influence of the climatic agency, as they were reported to do in later season of the year in Funkia undulata var. vitteta (a Hosta sp.) by FIGDOR (1914) and Pelargonium zonale by NOACK (1922). In the writer's Hosta, the deepening of green colour of leaves in later season is especially due to


the remarkable growth in size of green plastids in the cells with mixed kinds of plastids.

The presence of two or more different kinds of plastids , and not of an intermediate type, is probably due to the distinct individuality of different kinds of plastids themselves, rather than to the influence of cytoplasm upon the plastids as has been suggested by some authors. If the influence of cytoplasm be the prime cause, we must assume the selective bleaching power of the cytoplasm around each differant plastid in one and the same cell, so far as the case of the present study is concerned.

Some offsprings (Chloro-variegata and Medio-chlorinata) which got

green and yellow plastids only from the albomarginata parent by selfing, produced green, yellow and yellow variegate progenies only, and never threw albinos; and some (Medio-albinata and Albostriata) which got colorless and green plastids but not yellow, do not throw any

yellow progeny ; and some (Albo-chloro-variegata) which got green, yellow, and colourless plastids together 'separate' green, yellow, albino and variegated progenies.

Besides, as we see in tables 4-6 the chlorophyll characters of offsprings depend upon the colour of capsules more than upon the colour of leaves, and that is true even in different capsules on one and the same floral shoot, e. g. in table 6, Peds. 43, 44, 45, and Ped. 98 which

gave different sorts of vegetative 'separation' are the pedigrees from 4 different capsules on one and the same floral shoot.

As it has been described already, though some cytoplasmic substances in the pollen tube of these plants penetrated into the embryosac, probably with sperm cells, the plastid character of the male

parent did not appear in the offspring in Fl generation, so that we are probably justified in assuming that the pollen tube did not transmit its own plastids into the embryosac, or transmitted them only into synergid cells, or that they transmitted the plastids into the egg cell, but that they were either inhibited from developing further or digested by the action of cytoplasm of the egg cell, as CHMIELEWSKY and others assumed in other cases. If the latter be the case here, we may say that the maternal inheritance is the result of the action of cytoplasm of the egg cell; but still we can not say that the development of chloro

phyll characters in these variegated plants here concerned is due to the action of the egg cytoplasm but not due to the irregular distributions of different plastids into the daughter cells during the process of cell divisions.


From these data mentioned above the writer concludes 1) that the variegated progenies arise from the egg cells which have corresponding

plastids in leuco-state, 2) that qualitative differences as well as the difference in number of different kinds of plastids in the original cells, the modes of distributions of these plastids into the daughter cells during the process of cell division cause the different plastid characters of cells, in cooperations with the division of plastids themselves in the

cells of growing points, leaves and other parts of the plant.

In the case, when the original cell had a few colourless or yellow

plastids mixed with numerous green plastids, and they were distributed into the daughter cells equally in successive divisions, the plant will be

green in all appearance. Consequently we can reasonably assume that in apparently green progenies in the present study there might have been present some such pseudo-green plants, which gave rise to the striped plant as in F2 generation mentioned in p. 206.

The formation of chlorophyll pigments in chloroplasts is to be considered as the result of cooperation of some factor related to genes

(here the term gene is used for the idioplasmic substance carried through chromosome) and plastids themselves; therefore, when some deficiencies occur on the genes concerned, the plastids may develop to be colorless, yellow, orange yellow or pale green ones, thus producing albino, chlorina, aurea or pale green plants; and the combined effect of such deficiencies in the genes and the gene concerning distribution of

plastids, several kinds of variegated plants will be produced; and when the plastids themselves get some deficiencies, they may also become colorless, chlorina with several nuances, and pale green; and by combinations of normal and deficient plastids, variegated plants will result. In the cases due to the influence of different genes, those deficient characters in the progenies of hybrids between normal and deficient

plants or between the latter plants themselves will show Mendelian segregation, while in the case due to plastids they will not.

The effect of chlorophyll deficiencies in the present material of Hosta belongs to the latter case, namely the plastid inheritance.

Plastids in the different cells in the present plants do not influence each other in regard to the chlorophyll character, so that in the growing

points there may be a greater number of cells containing single kind of plastids, but a few with mixed plastids; in such cases the plants will be comparatively stable; but if the quantitative relation is reversed they will be generally variegated and unstable; the albomarginata and


medio-albinata are examples of the former, and albo-maculata , chlorovariegata and albo-chloro-variegata of the latter.

Summary

1. Plastid characters in Hosta japonica ASHERS. et GRAEBN. f. albomarginata MAKINO and 9 different kinds of progenies were investigated . The parent albomarginata plant had three different kinds of plastids , namely colorless, yellow and green plastids. Some of the progenies received only one kind of plastid, while others more than one.

2. The plastid characters show non-Mendelian inheritance in the seedlings from selfed plants.

3. By the crossing experiments the maternal inheritance of the character in question was determined.

4. Unlike the case of Funkia ovato (an allied species) studied by STRASBURGER, embryo formation is normal, no apogamy being found. From these facts and the results of crossing experiments with regard to

purple spots at the leaf base, the writer concluded that the maternal inneritance of plastid character is gametic.

5. Especially in the borderr line between two differently pigmented tissues of mature leaves, two or more different kinds of plastids in one and the same cell were observed in all variegated plants.

6. The plastids of male parent may or may not be transmitted into the egg cell. If the former be the actual case, the development of such plastids derived from male side must be considered as being

prevented from further development in the egg cytoplasm, and the present case of maternal inheritance is due to the inhibitory action of egg cytoplasm, but the various deficient chloroplast characters developed in the progenies are due to the individual characters of plastids themselves and to their irregular distributions into the daughter cells which may happen during the process of the cell division.

7. The writer considers that the variegated plants here concerned originate from a fertilized egg cell which had two or more different kinds of plastids transmitted from the embryosac mother cell.

8. There were observed between the neighbouring cells no influence of one kind of plastid upon another, concerning the formation of chlorophyll pigments characteristic to each kind of plastid.

In concluding the writer wishes to express her sincere thanks to Prof. K. Fujii for his kindly reading through the manuscript.

Botan. Inst., Sci. Fac., Imp. Univ. Tokyo, and

Tokyo Higher Normal School for Women

15


Bibliography

ANDERSON, E. G. (1923), Maternal inheritance of chlorophyll in maize. Bot. Gaz. 76: 411-418.

BAUR, E. (1911), Untersuchungen Uber die Vererbung von Chromatophorenmerk- malen bei Melandrium, Antirrhinum and Aquilegia. Zs. ind. Abst.-u. Vererb. 4: 81-102.

CHITTENDEN, R. J. (1925), Vegetative segregation. Hereditas 3: 355-442.

COLLINS E. J. (1922), Variegation and its inheritance in Chlorophytum elatum and Chlorophytum comosum. Jour. Genetics. 12: 1-17.

CORRENS, C. (1908), Vererbungsversuche mit bias (gelb) griinen and buntblatterigen Sippen bei Mirabilis Jalapa, Urtica pilulifera, and Lunaria annua. Zs. ind. Abst.-u. Vererb. 2: 291.

-(1909), Zur Kentnis der Rolle von Kern and Plasma bei der Vererbung. Zs. ind. Abst.-u. Vererb. 2: 331.

FIGDOR, (1914), Ueber die panaschierten und dimorphen Laubblatter einer Kurtur-form der Funkia lancifolia SPRENG. (After SCHURHOFF 1924).

GREGORY, R. P. (1915), On variegation in Primula sinensis. Jour. Genetics. 4: 305-321.

KONDO, N., MAEDA, M. and FUJIMOTO. S. (1925), Untersuchungen der weiss gestreiften Reispflanze ('Shimaine') (Rdsum4 from japanese article), Jour. Scient. Agr. Soc. (Nogaku-Kwaih6) No. 277: 15-16.

NOACK, K. L. (1922), Entwicklungsmechanische Studien an panaschierten Pelargonium. Jahrb. wiss. Bot. 61: 431-58.

RANDOLPH, L. F. (1922), Cytology of chlorophyll types of Maize. Bot. Gaz. 73: 337-357.

SCHURHOFF, P. N. (1924), Die Plastiden. Berlin. (LINSBAUER'S Handb. d. Anatom.)

STRASBURGER, E. (1877), Befruchtung and Zellteilung. Jena.WINGE, O. (1919), On the non-Mendelian inheritance in variegated plants. Comp.

rend. Labol. Carlsb. 14: No. 3, 1-20.

TERASAWA, Y. (1923), On the inheritance of Giboshi (Hosta). (Japanese) Jap. Jour. Genetics. 2: 13-21.

Explanation of Plates

Plate 13

All figures of leaves were reduced 4/5 nat. size; figures of tissues were drawn by the aid of a camera lucida at a 400 magnification, and reduced 4/5 in reproduction.

Fig. 1. a, an ordinary leaf of Hosta japonica. A SHERS. et GRAEBN. f. albomarginata MAKINO; b, a leaf of the same having a white area on one side of the midrib.

Fig. 2. A leaf of medio-albinata.

Fig. 3. A leaf of medio-chlorinata; 3, a, a portion of tissue showing abrupt transition from green to yellow; 3, b, cells containing small greenish yellow and ordinary green plastids side by side along the junction li

ne between green and yellow tissues.

Fig. 4. A leaf of yellow plant in the progenies of Ped. No. 69; 4, a, yellow palisade cells containing small yellow plastids.


Fig. 5. An albo-maculata leaf having narrow green margin.

Fig. 6. Albo-maculata leaves. a, a young leaf having the green margin; b, the

same leaf after further growth of one month when matured and the

median porticn became white; c, a leaf of a bud variation from the

plant, having no green margin.

Fig. 7. A leaf of chloro-variegate; 7a, a piece of spongy tissue, which shows

abrupt transition from green to yellow tissue; in the right side of

the figure there are shown greenish yellow plastids which are larger

than those shown in Figs. 3, a and 3, b; 7b, ceps in palisade parenchy

ma, having green and yellow plastids side by side in the same cell.

Fig. 8. a, a summer leaf of albo-chloro-variegata; b, a spring leaf from the

same plant; c, cells in palisade parenchyma, situated along the junc

tion line between green and white tissues, having ordinary green

plastids and large vacuolate colourless ones side by side in each cell.

Fig. 9. A shrunken leaf from (i).

Plate 14

Fig. 1-8 show cells and tissues in the marginal white part of a leaf of Hosta

japonica f. albomarginata. Figs. 2, 3, 6, 7 and 14 were drawn by the aid of a camera

lucida at a level giving the same magnifications with the microphotographs 1, 4, 5, 8,

and 13. Figs. 9-11 are microphotos.

Fig. 1. A part of colourless tissue, treated with potassium iodide-iodine solution.

•~ 400.

Fig. 2. A colourless cell, the same as that shown in Fig. 1, a. •~400.

Fig. 3. Cell with green and colourless plastids, treated with a potassium iodide

-iodine solution. •~400.

Fig. 4. The same cell as that in Fig. 3. •~400.

Fig. 5. A part of tissue having yellow cell a, and mixed cell b having green

and yellow plastids in it. •~400.

Fig. 6. The same as shown in Fig. 6, a and b. The plastids in black in b cell

show green ones, and the shaded ones in both cells yellow. •~400.

Fig. 7. Cell with green plastids, the same cell shown in Fig. 8, a. •~400.

Fig. 8. Tissue having green cells. •~400.

Fig. 9. A microphoto showing an abrupt transition from a green to a white

tissue in a leaf of a Medio-albinata plant. •~400.

Fig. 10. A part of median white part of the young leaf (Pl. 13, Fig. 6, a.) of

albo-maculata plant; photo was taken from the part marked with •~.

The dark oblique stripe in median portion of this figure shows the

region of a veinlet lying underneath. This darker colour is due to

the development of chloroplasts in the cortical cells surrounding

the vascular bundle. •~200.

Fig. 11. A part of palisade parenchyma marked with •~ in Pl. 13, Fig. 6, b,

photo taken about one month later than the stage shown in Fig. 10. •~

200.

Fig. 12. The abrupt transition between the marginal green and median white

tissue from the leaf shown in Pl. 13, Fig. 6, b. •~200.

Fig. 13. A part of a green spot in the colourless tissue remaining after the

fading of yellow colour of a leaf of the albo-maculata plant. •~400.

Fig. 14. The same cell marked with a in Fig. 13, showing four large green

plastids in it. •~400.

15*

Cytologia 1, 1929 Plate 13

Yasui: Maternal inheritance of plastid characters in Hosta

Cytologia 1, 1929 Plate 14

Yasui: Maternal inheritance of plastid characters in Hosta

Studies on the Maternal Inheritance of Plastid Characters ...

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