• Journal of Plant Biology
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• v.3 no.1
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• pp.1-15
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• 1960

HARN, Chang Yawl : Studies on the dimorphism and Fertility of Persicaria japonica (MEISSNER) Gross et Nakai. Kor Jour. Bot. 3(I) 1-15 1960 Numerous investigations, since the works of DARWIN, have been made regarding the heterostylous plants by JOST (1907), CORRENS (1924), LAIBACK (1924), LEWIS (1943), and many others. Studies on the heterostylous Polygomum, however, were not reported except for the buckwhent, Fagopyrum esculentum, which was investigated by SCHOCH-BODMER (1930), EAST (1934), FROLOVA & Co-Workers (1946), MORRIS (1947, 1951) TATEBE (1949, 1951, 1953), present author (1957), and others. It is because no heterostylous species, besides buckwheat, have been known to exist in the Polygonum family. The author, during his studies on both heterostylism and fertility of Polygonaceae, has found that the species, persicaria japonica (Meissner) Gross et Nakai, is not diecious as has been known in taxonomy, but in reality beterostylous both morphologically and physiologically. It was found that this plant, regarded by taxonomist, as a male plant setting no seed, actually set seed (botanical fruit) when legitimate combination was made. Since his brief report on the dimorphic phenomens of this plant in 1956, the author's further research on the manner of fertilization has revealed that this species is a peculiar type whose dimorphism has undergone extreme specialization structurally and physiologically, the short-styled individual behaving in nature as a male plant and the long-styled individual, as female, whereas in controllled pollination the plant shows highly differentiated typical dimorphism. When compared with the other dimorphous species of this family, F. esculentum and P. sentiosa. it has been clarified that these three species differ in the degree of differentiation of their dimorphism morphologically and physiologically. That is, P. japonica has developed such a high specialization as to mislead the taxonomists, while P. senticosa shows almost no noticeable difference between long- and shortstyled individuals retaining most of the inherent physiological character cmmon to the genus except for the fact that it has two forms of flowers. F. esculentum appears to have taken the intermediate position in every respect. The result obtained in the present experiment are summarized as follows: 1) P. japonica has two kinds of individuals, one long style-short stamened; the other, short style-long stamened. The floral structure of this plants shows typical characteristics of dimorphic heterostylism. The differentiation between the two forms of flower has proceeded so highly both in primary and secondary difference of flower structure that this may be regarded as the most specialized form of dimorphism. 2) The differences of floral structure between the long and short styled individuals are remarkable compared with the other dimorphic species of the family. 3) The stamens of long styled plants show the sign of deteriolation whereas those of the short styled flower are well-developed. 4) When legitimate combinations are made, both L- and S-styled individuals are fertilized well and set seed (fruit), while in the illegitimate combination no fertilization and seed setting occur. Physiologically this species exhibits the typical behavior of dimorphic plants. 5) The self-fertile character, so common in other species of the other non-heterostyle Polygonum family, has disappeared completely. 6) Under natural conditions, no or few seed setting is observed in short styled individuals that behave as if they were male plants. 7) In hand pollination, the combination of both $L{\times}S$ and $S{\times}L$ alike yield relatively good fertility and seed-formation, the behavior of short styled individuals in artificial pollination differing remarkably from that in nature. 8) Under controlled pollination, $L{\times}S$ combination sets far more seed than in the combination of $S{\times}L$. In the S-styled individuals, the fertilized flower has the tendency of its seed more readily falling off in every stage of seed development than in the L-styled individuals. 9) The behaviors of pollen tubes just parallels the results of fertility test. That is, in the illegitimate combination, L-selfed, $L{\times}L$, S-selfed, and $S{\times}S$, the growth of pollen tubes is checked in the style, while in legitimately combined $L{\times}S$ and $S{\times}L$, the pollen tubes grow well reaching the ovaries within 40-50 minutes after pollination. The response of short styled individuals, known as male plant among taxonomists, is identical, as far as behavior fo pollen tube growth and fertilization are concerned, to that of long styled individuals, the so-called female plant. 10) The pollen grains from the short-styled plants are complete and fertile, whereas 70% of those of L-styled are found to be abortive, i.e., empty contents. 11) The remaining 30% of pollen of L-plant shows varied degree of stainability when stained with iron-aceto-carmine......mostly light red, while the pollen grains of S-style individuals are dark brown indicating complete fertility and viability. 12) The abundance of sterile pollen in L-styled and the nature of seed-dropping which occurs in S-styled individuals appear to be the main causes why the short styled individuals bear no seed in nature. Under controlled legitimate union, $S{\times}L$, the careful and elaborate pollination would give the S-styoled flowers the opportunities to receive the fertile pollens, though few in number, from L-styled plant, thus enabling S-plant to bear seed. 13) This species is not dioecious as is regarded by taxonomists, but typical dimorphic plant which has so highly specialized in floral structures and funcitons that the long-styled plant behaves just like a female individual; and the short-styled, like a male.

• Development and Reproduction
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• v.12 no.2
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• pp.169-181
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• 2008

Reproductive ecology of the silver pomfret, Pampus argenteus were investigated by histological observations and morphometric data. Samples were collected by the stow net at the coastal area of Jaun-Do, Muan-gun, Korea, from January to December, 2006. P. argenteus is dioecious, the ovary is composed of many ovarian lobules, showing a pair of saccular structure, and the testis is composed of many seminiferous lobules, showing a pair of lobular structure. From February (growing stage) to September (after spawning), monthly changes in the gonadosomatic index, hepatosomatic index, and condition factor in females and males showed similar patterns with the gonad developmental phases. Judging from the results of their indice, it is assumed that spawning in females and males occur from May to July. The reproductive cycle can be classified into five successive stages in females: early growing stage (February to March), late growing stage (March to April), mature stage (March to July), ripe and spent stage (May to July), and recovery and resting stage (July to February); in males, the cycle can be divided into four successive stages: growing stage (February to April), mature stage (March to June), ripe and spent stage (May to July), and recovery and resting stage (July to February). According to the frequency distributions of egg diameters in the breeding season, P. argenteus is presumed to be spring-summer spawning species and polycyclic species to spawn 2 times or more during one spawning season. Number of total eggs in absolute fecundity were proportional to body length and body weight, respectively. Number of total eggs in absolute fecundity per body weight were also proportional to the body length, but if the increase of body weight considerably increased, rather total eggs in relative fecundity decreased with the increase of body weight. Percentage of first sexual maturity of P. argenteus were over 50% in females and males of 12.1 to 15.0 cm in body length, and 100% for fishes over 18.1 cm in length. Therefore, both sexes were regarded to be sexually mature at one year of age.

• Development and Reproduction
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• v.9 no.2
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• pp.95-103
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• 2005

Reproductive cycle, gonadosomatic index(GSI), egg diameter composition, first sexual maturity, sexually matured length(50% of first sexual maturity), and sex ratio of Amusium japonicum japonicum, were investigated by histological observations and morphometric data. Samples were collected monthly from the subtidal zone of Sogwipo, Jejudo, Korea, for two years. The sun and moon scallop Amusium japonicum japonicum is dioecious. Monthly variation in the GSI showed similar patterns with the reproductive cycle. Ripe oocytes were about $70{\sim}90\;{\mu}m$ in diameter and had thick egg membranes. The spawning period was from November to January, and the main spawning occurred between November and December when the seawater temperature was relatively low. From monthly changes in egg diameter composition, the spawning period was once a year, although the number of spawning frequencies is assumed to occur more than twice during the spawning season. The reproductive cycle of this species could be divided into five successive stages: early active stage(April to June), late active stage(June to September), ripe stage(October to November), spawning stage(November to January), and spent/resting stage(February to April). First sexual maturities in female and male scallops ranging from 85.1 to 90.0mm in shell length were over 50% and they were 100% for scallops over 90.0mm in shell length. In this population, sexually matured shell lengths(50% of rate of group maturity) in females and males were 86.96 and 86.59mm, respectively. The female to male sex ratio among individuals over 85.1mm in shell length was not significantly different from 1:1($X^2=0.18$, p>0.05). No evidence of hermaphrodite was found in histological sections of any scallop examined.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.125-134
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• 1980

The dovelopment of the gonads, gametogenesis and the reproductive cycle of the topshell, Turbo cornutus Solander, which is one of valuable food animals fom Korean waters were studied by photomicroscophy. The materials were monthly collected from Bangeojin, Jeongjari and Dangweol, all these places being located in the south-eastern part of Korea, for one year from March 1979 to February 1980. Topshell is dioecious and oviparous. Gonad is situated on the surface of liver, which lies posteriorly. The surface of ovary and testis is covered with a fibrous membrane, membrane of connective and muscular fibers and then an outermost layer of simple-columnar epithelial cells which are composed of cuboidal and columnar mucous gland cells. Primordial germ cells develop on the germinal epithelium of ovarian and testicular lobuli which are originated from the fibrous membrane and extend toward hepatic gland. Undifferentiated mesenchymal tissue and pigment granular cells are abundantly distributed between the growing oocytes and spermatocytes in the early development stages. With the further development of the ovary and testis these tissue and cells gradually disappear. Then the undifferentiated mesenchymal tissue and pigment granular cells are considered to be related to the growing of the oocytes and spermatocytes. Early multiplicating oogonium is ca. $10\mu$ in diameter and nucleushaving a central nucleolus is ra. $8\mu$. As the oocytea grow to ca. $50-60\mu$ by the increase of cytoplasm, the oocytes become look like bunches of grapes which are attached to ovarian lobuli. Mature eggs are ca. $180-210\mu$ in diameter and it is surrounded by a gelatinous membrane of ca. $10\mu$ in thickness. After spawning, undischarged ripe eggs and spermatozoa remain in the ovary and testis respectively for some time. Then they finally degenerate, and proliferation of new oogonia and spermatogonia occur along the germinal epithelia of newly developed ovarian and testicular lobuli. Reprocuctive cycle of Turbo cornutus could be classified into five successive stages: multiplicative, growing, maturer spent and recovery stages. Spawning occurs from August to November with Peak spawning from early September to late October.

• Development and Reproduction
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• v.11 no.3
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• pp.155-165
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• 2007

Gonad index (GI), conditon index, the reproductive cycle with gonadal development of the Neptunea (Barbitonia) arthritica cumingii, were investigated histologically, based on the samples which have been collected from the subtidal zone of Oeyeondo, Boryeong, Korea from January to December, 2006. Neptunea (Barbitonia) arthritica cumingii is dioecious and oviparous. Monthly changes in the gonad index (GI), studied for determination of spawning period, were closely associated with gonad developmental phases. The GI reached a maximum in April, and gradually decreased from May to August due to spawning. The gonadsomatic index and condition index showed similar patterns to gonad developmental phases and the spawning period. The reproductive cycle according to gonad developmental phases of this species can be classified into five successive stages in females and males: in females, early active stage (September to October), late active stage (November to February), ripe stage (February to June), partially spawned stage (May to August) and recovery stage (June to August); in males, the early active stage (September to October), late active stage (November to February), ripe stage (February to June), copulation (April to July), and recovery stage (July to August). Spawning occurred between May to August in females and April to July in males, and spawning peak in females was observed between June and July when the seawater temperature rose to above $19^{\circ}C$. Percentages of first sexual maturity of female and male snails ranging from $50.1{\sim}60.0\;mm$ in shell height were over 50%, and 100% for snails over 60.1 mm in shell height. The sex ratios of females to males were not significantly different from a 1:1 sex ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.563-574
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• 1986

The structure of gonads, gametogenesis and reproductive cycle of the jackknife clams, Solen strictus and Solen gordonis were investigated mainly by histological observation. The first species used were monthly sampled at the coastal area of Dadaepo, Pusan, Korea and Naechodo, Kunsan, Korea for one year from February 1982 to January 1983. The second species were monthly sampled at the sand beach of Dadaepo, Pusan, Korea, from February 1982 to January 1983. Sexualities of Solen strictus and Solen gordonis are dioecious, and these species are oviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary was composed of a number of small ovarian sacs and the testis was composed of several testicular lobuli which from the tubular structure. Early multiplicating oogonium was about $10{\mu}m$ in diamater. Nucleus and nucleolus, at that time, were distinct in appearance. Each of the early growing oocytes made an egg-stalk, connected to the germinal epithelium of the ovarian sac. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed in the ovarian sacs in the early development stages. With the further development of gonad, these tissue and cells gradually disappeared. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells function as nutritive cells in the formation and development of the early stage germ cells. Mature oocytes were free in the lumen of ovarian sacs and gradually become round or oval. Ripe oocyte was about 80 to $90{\mu}m$ in diameter. With the further development of testis, each of the testicular lobuli formed stratified layers composed of spermatogonia, spermatocytes, spermatids and spermatozoa in groups on the germinal epithelium. After spawning, the gonad gradually degenerated, and disorganized completely. Then new differentiated tissues were rearranged next year. The annual reproductive cycle of those species could be classified into five stages; multiplicative, growing, mature, spent, degenerative and resting stage. It seems that the spawning season is closely related to the water temperature, and the spawning of Solen strictus occurs from June to July at above $20^{\circ}C$ in water temperature. The peak spawning season appeared in June at Dadaepo and in July at Kunsan, The spawning of Solen gordonis occurs from May to June with the peak spawning season in June. Percentages of the first maturity in female of Solen strictus ranging from 5.1-6.0 cm and 7.1-8.0 cm in shell length were $50\%$ and $100\%$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.702-708
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• 2002

Although Umboniunm thomasi is one of marine mollusc (Archaeogastropoda: Trochidae) inhabiting the sands in the intertidal zone of the west coast of Korea, aspects of its reproductive biology are still not too well known. Reproductive cycle, gametogenesis, and first sexual maturity of U. thomasi collected at the west coast of Buan-gun, Jeollabuk-do, Korea were investigated monthly from January to December 1999. U. thomasi was dioecious, and an oviparous. The gonad was placed in the rear of the flesh part in the spiral shell. The external colors of the ripe ovary and testis appeared to be green and milk-white or yellowish white, respectively. Meat weigh rate peaked in July ($37.5\%$). And then the value sharply decreased in September ($28.3\%$), thereafter, gradually increased in November ($31.7\%$). Fully ripe oocytes were approximately 100$\~$110 $/mu$m in diameter, and their cytoplasm contained a great number of yolk Branules. Based on the monthly changes of the Bonadal development, gametogenesis, and meat weight rate, the reproductive cycle of U. thomasi could be devided into five successive stages: early active (November to April), late active (February to May), ripe (April to August), spawning (July to October), and recovery (September to February). Gonadal development and spawning were closely related to the seawater temperature, the main spawning occurred in September when the temperature reached above 24.2$^{\circ}C$. Individuals of 4.4 mm and less in shell height could not take part in reproduction in both sexes. Percentages of first sexual maturity of female and male shells ranging from 5.5 to 6.4 mm were $55.0\%$ and $61.9\%$, respectively, and $100\%$ of those over 7.5 mm in shell heights in both sexes participated in the reproduction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.629-636
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• 1999

Gonadal development, gametogenesis, reproductive cycle, egg-diameter and composition, condition factor, and the first sexual maturity of the clam, Potamocorbula amurensis were investigated by histological observation. Samples were collected monthly from the tidal flat of Moonpo, Puan-gun, Chollabuk-do, west coast of Korea from November 1996 to October 1997. P. amurensis is dioecious and oviparous. The gonads were composed of a number of gametogenic follicles. The oogonia and fully ripe oocytes were $9\~12\mu$m and $50\~60\mu$m in diameter, respectively. Each of the spermatogenic follicle formed stratified layers composed of spermatogonia, spermatocytes spermatids, and spermatozoa in groups on the follicular wall. The reproductive cycle of P. amurensis could be classified into five successive stages: early active, late active, ripe, partially spawned, and recovery. Spawning occurred twice a year from May to July and from September to October, the main spawning seasons also appeared twice a year between May and June, and in October when the water temperatures reached above $18^{\circ}C$. The monthly changes in the condition factor were closely related with the reproductive cycle. Minimum size for the sexual maturation of female and male were 8.1 mm in shell length. There were two patterns for the gametogenesis: 1. After spawning, the undischarged ripe oocytes and spermatozoa in the follicles were degenerated and absorbed, but in part, the existing follicles were not contracted significantly and then they took part in new gametogenesis within one or two months (especially, in summer). 2. After spawning, each follicle was contracted, thereafter gametogenesis again occurred in newly formed follicles.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.512-520
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• 2020

We assessed the nectar source potential of a prospective honey plant, Idesia polycarpa, by analyzing nectar volume, free sugar content, and free amino acid content. Idesia polycarpa is a dioecious tree; the males bloom approximately four days earlier than females, and the blooming period is approximately 17 days-from March 14th to March 30th. Upon investigating the patterns of nectar secretion, it was found that male flowers peak on the third day of blooming at 5.0 ± 2.5 μL, and female flowers peak on the second day of blooming, at 1.1 ± 0.4 μL. There was a significant difference between males and females in the total nectar volume (9.7 ± 2.9 μL for males and 1.7 ± 0.5 μL for females) and the dried nectar volume (2.2 ± 0.6 μL for males, 0.8 ± 0.3 μL for females) during the blooming period. The free sugar content of floral nectar was 54.6 ± 15.4 ㎍/μL for males and 20.5 ± 4.9 ㎍/μL for females, and the sugar content per flower was higher in males (170.7 ± 15.4 ㎍) than in females (24.9 ± 5.5 ㎍). Our analysis of the amino acid content showed that 20.4 ± 3.9 mg/L (comprised of 19 amino acids) is produced in male flowers and 3.2 ± 0.1 mg/L (11 amino acids) in female flowers. In the male flower, the main amino acid was glutamine, followed by asparagine and proline, whereas in the female nectar, asparagine was the main amino acid, followed by glutamic acid and glutamine. Idesia polycarpa blooms after the blooming period of a major honey plant, Robinia pseudoacacia, and its nectar volume and nectar characteristics, such as free sugar content and amino acid content, make it a viable honey plant.