• The Korean Journal of Ecology
• /
• v.8 no.3
• /
• pp.127-132
• /
• 1985

In this study, the competitive development of leaf in Amaranthus and Chenopodium were invesitgated by the complemented plastochron index. The value of PI for Amaranthus was not varied with competional ratios, while for Chenopodium it was varied. Namely in Chenopodium, the plastochron 1 was increased as competitional combinations, the plastochron 2 was decreased. These results indicated Amaranthus had advantage in competition over Chenopodium. It is surmised that these results were exhibited differences in photosynthetic pathway between Amaranthus (C4 plant) and Chenopodium (C3 plant). The linear patterns were clearly demonstrated by the differences in leaf arrangement between Amaranthus (alternate type) and Chenopodium (opposite type). From these resultss, use of plastochron seems to a useful means of evaluating plat response to various environments.

• The Korean Journal of Ecology
• /
• v.15 no.1
• /
• pp.9-18
• /
• 1992

Nitrate reductase activity(nra) were analysed in roots, stems and leaves plants in relation to different nitrogen sources and plastochron ages. Nra in roors and stems of soybean observed no differences in influence the nitrogen sources and plastochron ages, and the values showed to be only 5% of NRA in leaves. On the other hand,NRA in the leaves showed different result to nitrgen sources and plastochron ages. When the plants were less than PI6.0, NRA in leaves had being proportional to the concentration of nitrate and distingush decreased with an increasing plastochron age. At the later stage, upper than PI 8.0, the actvity had not effect to nitrate and plastochron ages. These results indicated that nitrate reduction in soybean was in early leaves.

• The Korean Journal of Ecology
• /
• v.15 no.1
• /
• pp.1-7
• /
• 1992

The dvelopment of leaves in soybean(glycine max cv. yellow grain and glycine max cv. black grain)plant were assessed for the applicability of the plastochron index. The plastochron ages versus time in days were respectively 6.4 days in black grain and 9.6 days in yellow grain. Plots of plastochron indes(pi) versus time were linear, there were two distinct groups of regression line. when a point of intersection in the lines were upper than the reference length, pi was estimated n+(ln Ln-ln LR)/(ln Ln-ln Ln+2) or (n-1)+(ln Ln-1-ln LR)/(ln Ln-1-ln Ln+1) . When a point of intersection in the lines were less than the reference length, pl was estimated n+(ln Ln-ln LR)/(ln Ln-ln Ln+2) or (n-1)+(ln Ln-1-ln LR)/(ln Ln-1-ln Ln+1) . The growth rate of black grain plants analysed by pl was higher than yellow grain plants.

• The Korean Journal of Ecology
• /
• v.8 no.1
• /
• pp.1-5
• /
• 1985

The plastochron index (PI) provides possibility on studies of the effects of various environmental factors on morphological and physiological development of plants. The PI of Erickson and Michemlini(1957) could be used merely when leaf n is longer an leaf n+1 is smaller than the references length at any time. If both the lengths of leaf n and n+1 are smaller or longer than the reference length, it could not estimated. In this study, the PI of Erickson and Michelini was complemented and the linear patterns according to leaf arrangement was represented, PI is n-(lnLR-lnLn)/(lnLn-lnLn+1). And when both the lengths of leaf n and n+1 are longer than the length of reference, PI is n+1+(ln Ln+1-lnLR)/(lnLn-lnLn+1). The linear model of PI is changed by the various environmental factors and the linear patterns are different according to leaf arrangement. According to leaf arrangement, the equation of the general regression lines is Yin-(i-j)=a-(n-1)(q1+...+qi-1)-(q1+...+qj-1)+rt+$\varepsilon$. Where Y:the logarithmic of the leaf length in question, i:leaf number hang on the one node, n:the number counting from base, q:spacing on the Y-axis, j:0, 1, 2, ..., r:slope, t:time, $\varepsilon$:error.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.1
• /
• pp.1-5
• /
• 2000

Leaf area is critical for crop light interception, and thereby has a substantial influence on crop yield. This experiment was conducted to characterize the development of soybean [Glycine max (L.) Merr.] leaf area. Plastochron index and leaf relative growth rate of Jackson was contrasted with the PI416937, which also has demonstrated tolerance to drought. First, plastochron ratio (PR) and plastochron index (PI) were evaluated in greenhouse to compare the leaf growth rate between two genotypes under well-watered condition. There was reasonable constancy of PR between two genotypes. The PR means of Jackson and PI416937 were 0.41 and 0.44, respectively. A fairly smooth increase of PI during vegetative stage was observed. Second, the relative growth rates were graphed against leaf area, normalized with respect to final leaf area, under well-watered and water-deficit conditions. Leaf growth was sustained longer in well-watered condition than water-deficit condition and there was a sizable proportion of leaves which was ceased earlier their growth in water-deficit condition compared to well-watered condition. The leaf relative growth rate of Jackson until leaves had completed at 45% of their growth during water deficit period was higher than that of PI416937.

• The Korean Journal of Ecology
• /
• v.9 no.1
• /
• pp.1-7
• /
• 1986

plastochron index was used as a measure for the nitrate reductase activity (NRA) in Amaranthus retroflexus, Chenopodium album var. centrorubrum and Glycine max. The material plants treated with $NO_3$-N had higher NRA than those treated with ${NH_4}^+$-N. High NRA were found in young tissues which have low PI or LPI in both A. retroflexus and C. album. These results indicated that this enzyme decreased with increasing plastochron index of the extracted tissues. High level of NRA was detected in Glycine max leaves at PI 4.0. On the other hand, there were no significant differences for PI among $NO_3$-treated, ${NH_4}^+$-treated and control in both stems and roots.

• The Korean Journal of Ecology
• /
• v.22 no.3
• /
• pp.155-161
• /
• 1999

The plastochron index (PI) according to leaf development of Ambrosia artemisiifolia var. elatior were estimated. The amount and composition of monoterpenes in the leaves of A. artemisiifolia var. elatior were determined, and the seasonal monoterpene variations in representative of plastochron index were investigated. The total amount of monoterpenes in A. artemisiifolia var. elatior was increased continuously from PI 2.0, the highest amount was in PI 11.89. The major monoterpenes in A. artemisiifolia var. elatior consisted of 29 compounds. The leaf monoterpene fraction of A. artemisiifolia var. elatior were dominated by No.2, octene, α-pinene, β-myrcene, 1,3,6-octatrine, endo-borneol and (-)-bornyl acetate.

• Proceedings of the Zoological Society Korea Conference
• /
• 1998.10b
• /
• pp.212.2-212
• /
• 1998

No Abstract, See Full Text

• The Korean Journal of Ecology
• /
• v.17 no.2
• /
• pp.131-141
• /
• 1994

One-year-old yellow-poplar (Liriodendron tulipifera L.) and sweetgum (Liquidambar styraciflua L.) seedlings were exposed to 0.10 ${\mu}l/l\;O_3$and simulated acid rain at pH 3.0 for ten consecutive weeks. Shoot height growth (SHG), fresh weight (FWT), dry weight (DWT), apparent plastochron duration (APD) and foliar nutrient concentrations were measured. None of growth measurements, except the apparent plastochron duration (APD), were significantly affected by any treatment in yellow-poplar seedlings. APD was approximately 30% higher in seedlings exposed to $0.1{\mu}l/l\;O_3$ ＋ pH 5.6 solution than any other treatment. Ozone significantly reduced SHG of sweetgum seedlings by 24% at the end of the ten-week fumigation. There were also significant effects of single and combined effects of ozone and simulated acid rain on APD in sweetgum. APD was significantly increased by 19.8% and 25.7% in seedlings exposed to $0.1{\mu}l/l\;O_3$ and pH 5.6 solution, respectively, and resulted in 46.1% higher APD in seedlings exposed to $0.1{\mu}l/l\;O_3$ + pH 5.6 solution compared with seedlings exposed to $0.0{\mu}l/l\;O_3$ ＋ pH 3.0 solution. Phosphorus and sulphur were significantly greater in seedlings exposed to simulated rain at pH 3.0 compared with pH 5.6 for both species. Foliar S concentration was higher in seedlings exposed to $0.0{\mu}l/l\;O_3$ ＋ pH 3.0 than in seedlings exposed to any other treatment in sweetgum. Ozone significantly increased Ca in sweetgum seedlings, however, ozone reduced Ca in yellow-poplar. Ozone also reduced S and Mg in sweetgum seedlings.

• Journal of Korean Society of Forest Science
• /
• v.86 no.4
• /
• pp.407-414
• /
• 1997

The resistance of a non-transgenic poplar clone, 'Ogy' and three transgenic poplar lines to the cottonwood leaf beetle, Chrysomela scripta F., was evaluated by in vitro feeding. The lines were transformed with neomycin phosphotransferase II(NPT II) as a selectable marker, proteinase inhibitor II(pin2) as a resistance gene, and CaMV 35S as a promoter. An efficient method of sterilizing the beetle eggs and introducing them into plant tissue cultures was developed. The resistance of the transgenic lines was investigated in terms of effects tin leaf area consumed, insect weight, insect developmental stages, and plantlet root dry weight after feeding. Also, leaf area consumed was examined by leaf age as measured through leaf plastochron index(LPI). The leaf area consumed and insect weight were highly significant between transformants and control, and insect development in vitro was significant among the transgenic lines. Larval infestation was the most severe around LPI 4 to 5 which were young leaves. The system provided a quick, highly controlled method to screen developing transgenic plantlets directly.