Nishi, Katsuhisa

Okayama University Digital Information Repository

A STUDY ON THE FOLIAGE ARRANGEMENT OF BARNYARDGRASS AND RICE PLANT

Okayama University Scientific Achievement Repository

Ber. Ohara Inst. landw. Biol.， Okayama Univ. 19 : 145-148 (1987) A STUDY ON THE FOLIAGE ARRANGEMENT OF BARNYARDGRASS AND RICE PLANT Katsuhisa NISHI INTRODUCTION Barnyardgrass， the primary weed of paddy field in japan， was thought to be a plant mimetic to rice (Kasahara 1968， Yabuno 1975). The plant type， the forms of leaves and stems resemble rice， and we can hardly find out barnyardgrass in paddy fields at the vegetative growth stage. Tsunoda ( 1960) described that the rice plant has two types of foliage arrangement， one is sparse and another is dense arrangement. The former is a low fertilizer-response variety and the latter is high fertilizer-response variety. It is interesting that what kind of foliage arrangement barnyardgrass has in comparison with rice plant. 1n this study， the cover degree of these foliage arrangement was measured and compared. MATERIALS AND METHODS Rice (Oryza sativa L. Akebono) and barnyardgrass (Echinochloa 0りんzicola Vasing. and Echinochloa crus-galli Beauv. var. 10門nosensisOhwi) were studied. Seedllings of these plants were transplanted separately one per hil at 28 x 30cm intervals in each 9m2 plot of the paddy field in our institute in June 25， 1983. These seedlings were 15 cm high and had five leaves. They grew from luly to August and attained a height of 70-80cm at the end of August. The overhead view of the plants was photographed on August 28. Cover degree of one typical plant each was measured by the following method. The paper that six concentric circles having equal size were described which further divided into twenty-four equal angles and each section have equal size of 0.32 cm2 was put upon the overhead view of the photograph (7.5 X 11.0 cm) of each plant. Then the center of the circle and overhead view of the primary stem were overlapped (Fig. 1). Cover degree of the plant in every section was measured， those of each section were added and those of each plant were calculated. Institute for Agricultural and Biological Sciences， Okayama University， Kurashiki 710 Japan Received June 19， 1987 146 Katsuhisa Nishi FIG. 1. Overlapping of plant (overhead) and the paper of concentric circles RESUL TS AND DlSCUSSION Fig. 2 shows the overhead view of the populations and individuals (rice and two species of bar町 ardgrass).In the populations and indi-viduals， the form of leaves of rice plant and E oryzicola resembled each other. The tip of the rice leaves are sharper than E. oryzicola and the central part of the latter is closed in with leaves， but E. crus-galli var. formosensis has much more space among their leaves than the other two specles. Fig. 3 shows the distribution of cover degree in every concentric circle around the primary stem with three species. In the central circle (19 crn diameter) of the plant， the cover degree of E oryzicola and rice plant are 80 and 65 %， respectively and that of E crus-galli var. fonηosensis is 49 %. Especiall y tha t of E crus-gall i var. formosensis is less than 50 % and this means that it has much space around the main stem. In the second circle， this order did not change. The cover degree of E. oryzicola is larger than that of the other two species in al circles. Thus， itis thought that E oryzicola， a mimetic plant of rice， has dense foliage arrangement around the center of plant. On the contrary， E. crus-galli var. formosensis has sparse foliage arrangement around the center. The sparse foliage arrangement of this species was observed also in the population in Fig. 2. Both plants are the primary weeds of paddy fields in ]apan， but their foliage arrangement is different as described above. Nishi (1984) measured the angle of lamina inclination of rice plant and barnyardgrass， and showed that a proportional correlation is found A. B. C. Foliage Arrangement of Barnyardarass 147 13121場所.. 三宅1事:矧[河J13TF134iJま司l 仁 I 冒E 一、 三姐圃""-国ー ' 吋F二)キミ:jiZFil|‘Lj， F三イ三二一，.I L仏I予ママ予1雪幻7一.ρ川川Iい円円円f之てぺIλiJ?ごI、-入¥FIG. 2. Overhead view of the population and the individuals of rice plant and barnyardgrass A. Oryza sativa L. Akebono B. Echinochloa 0り'zicolaVasing. C. Echinochloa crua-galli Beauv. var. formosensis Ohwi right : individuals left : population between the base of lamina height of rice plant and E oryzicola from their land surface and angle of lamina inclination. However， E crus-galli var. formosensis is different from these. The angle of lamina inclination is large and is independent of tne base of lamina height from land surface. It shows that E crus-galli var. formosensis has a close straight line of lamina 148 Katsuhisa Nishi 80 r---， 60 ~ ω40 8 司ω 〉。ω20 。I_Echtnochloa oryzicola.Vasing. 2 3 4 5 6 ，Echinochloa crus-ga/Ji Beauv. var. formosensis Ohwi The number of circles from the primary stem FIG. 3. Distribution of cover degree in every concentric circle around the primary ・stemand leaf sheath. These characters were seen in prostrate type of barnyardgrass， E.crus-galli Beauv. var. crus-galli which grows in upland and paddy fields. Thus， the character of sparse foliage arrangement is considered to be connected with the straight line construction of lamina and leaf sheath. However， plant type of this species is erect different from other varieties of E crus-galli sp. distributed in upland and paddy fields (Yabuno T. 1975). Therefore， E crus-gallivar.formosensisisthoughtto be an intermediate to paddy field type (erect) from upland field type (prostrate) of E crus-galli sp. SUM勘IARYThe foliage arrangement of two species of barnyardgrass. growing in only paddy field and rice plants in the vegetative growth stage was investigated and their cover degrees were compared. One barnyardgrass， E oryzicola， has more cover degree than rice， suggesting that it is a closed-leaved type around the center of the plant， with dense foliage arrangement but another barnyardgrass， E. crus-galli var. formosensis is different from the former and has the sparse foliage arrangement which is a character of E. crus-galli sp. REFERENCES Kasahara， Y. 1968. Weeds of ]apan illustrated. p. 406-409， Yokendo， Tokyo. Nishi， K. 1984. Studies on the plant type of barnyardgrass. Weed Research (J. W. S. ].). 29 Suppl. 113-114. Tsunoda， S. 1960. Morphology and function of rice. p. 186-189， Nogyo Gijutsu Kyokai， Tokyo. Yabuno， T. 1975. The classification and geographical distribution of the Genus &hinochloa. Weed Research (J. W. S. ].). 20 : 97-104. 

A STUDY ON THE FOLIAGE ARRANGEMENT OF BARNYARDGRASS AND RICE PLANT

Abstract

Similar works

Full text

Available Versions

Okayama University Digital Information Repository

Okayama University Scientific Achievement Repository