STUDIES ON THE DIMORPHISM AND FERTILITY OF PERSICARIA JAPONICA (MEISSNER) GROSS ET NAKAI

Persicaria Japonica (MISSNER) Gross et Nakai의 이형화와 수정력에 관한 연구

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.

P. japonica가 분류학에서 말하는거와 같이 리웅이주가 않이고 이형호장물이라는 것을 훌견하고 수년간 이 식물의 장주화개체, 단주화개체간의 화기의 형태, 수정력, 화분관의 행동 및 L, S주의 화분의 임, 불임등을 조사해 보았드니 이 식물은 이형수장물중에서도 L, S주간의 분화가 가장 심하게 되어 있어 일부기관이나 기능은 웅웅이주와 같이 변해버린 특수한 이형수장물이라는 것이 명백히 되었고 이 장물은 장물조포체세대의 성의 분화가 생기는데 이형현상을 거쳐서 되는 경우도 있지 않나 하는 것을 가정케하는 한 증거가 될수 있다고 생각된다. 또한 여뀌과의 다른 이형예장물인 F. esculentum이나 P. senticosa와 비교해 보면 이 장물이 가장 L, S 주간의 분화가 심하고 F. esculentum은 중간, P. senticosa는 가장 미분화상태에 있어 삼종외 여뀌과 이형예장물간에 그 분화의 정도에 gradation이 생겨 있다. 이제 실험결과릎 요약하면 다음과 같다. 1) P. japonica는 화주장, 화사장, 등의 제일차의 형태적 차이뿐만 않이라 제이차적 형이도 대단히 심한 Dimorphism을 나타내고 있다. 2) L, S주의 화기의 차이는 동과의 타이형예작물에 비해 극경호 분화되어 있다. 3) L, S주의 웅예를 보면 S주는 대단히 발달되어 있는 반면에 L주의 웅예는 애예된것 같은 느낌을 주고 있다. 4) 적법수분에 의하면 L, S주가 다 결실이 잘 되지만 불적법수분에서는 수정결실이 전혀 안된다. 수정생리상으로도 뚜렷한 이형예작물이다. 5) 자가가임의 성질 또는 동형화간의 수정력은 완전히 상실하고 있다. 여뀌과의 타이형예작물과는 이 점에 차이가 심하다. 6) 자연상태하에 있어서는 S주는 결실이 거이 안되어 마치 \ulcorner주와와 같은 외관을 나태내고 있다. 7) 인공수분에서는 $L{\times}S$나 $S{\times}L$ 주 수정결실이 다 되어 S주의 행동은 자연상태하에서 와는 대단히 상이하다. 8) L주에 비해 S주는 수정후 용과가 더 심하다. 9) 화분관의 행동은 수정력과 완전히 일치된다. 즉 L-selfing, $L{\times}L$, S-selfing, $S{\times}S$등의 부적법 수분에서는 화분관은 화주의 미중에서 정지되지만 $L{\times}S$, $S{\times}L$,에서는 수분 약 40-50분 후이면 화분관은 자방까지 도달된다. 10) S주는 웅본으로 오인되어 있지만 인위적법수분을 하면 수정력이나 화분관의 행동은 L주에서와 동일하다. 11) S화분은 완전하지만 L화분은 약 70%가 내용공허한 Adortive pollen 이다. 12) L화분중 나머지 30%도 S화분에 비해서 염색도가 낮은것이 많고 S화분 같이 농염되는 것은 극히 소수이다. 13) 본장물은 분화가 고도로 진행된 전형적인 이형예작물이여 마치 Dimorphism 에서 Dioecious 에로 이행되는 수가 있다는 것을 표시하는 증거가 되는 것 같다.