I. 강원도 춘천지방에서 주로 재배되는 수도 품종 20개를 공시재배하여 출수기에 신장절위(간선단으로부터 4 개절위)경엽에 대한 형태조사를 한 바 그 결과는 다음과 같다. 1. 공시한 20 개품종의 평균엽면적은 제 1 엽 18.61 cm2 , 제 2 엽 21.84 cm2 , 제 3 엽 21.52 cm2 , 제 4 엽 18.56 cm2 로서 제 2 엽과 제 3 엽이 크고 제 1 엽과 제 4 엽이 작았으며 엽신중은 제 1 엽 97.0 mg, 제 2 엽 118.1 mg, 제 3 엽 115.4mg, 제 4 엽 95.3 mg로서 엽위별의 비중은 전기 엽면적의 경우와 같았고 엽초중(절당)은 제 1 엽초 176.3 mg, 제 2 엽초 163.7 mg, 제 3 엽초 163.4 mg, 제 4 엽초 123.9 mg 로서 절위가 상승함에 따라 현저히 컸다. 또한 엽중(엽신+엽초)은 절위당 제 1 엽 273.3 mg, 제 2 엽 281.8 mg, 제 3 엽 278.8 mg, 제 3 엽 219.1 mg로서 엽위별의 제2 및 제3엽이 컸고 제1엽과 제4엽이 적었으며 고간중(엽신+엽초+간)은 제1절위 374.4 mg, 제2절위 418.2 mg, 제3절위 446.1mg 및 제4절위 362.1 mg로서 역시 중간절위가 크고 상위와 하위에서 적었다. 2. 신장 절위 경엽의 품종간 변이계수를 산출하여 본즉 엽면적에 있어서 12.75%, 엽신중 15.29%, 엽초중 15.90%, 절간중 11.42%, 엽중(엽신중+엽초중) 15.45% 그리고 엽중 13.24%였으며 각절위에 있어서 엽면적, 엽신, 엽초, 간중등의 품종간 변이계수는 간중을 제외하고는 모두 제2 및 제3절위에 있어서 작았고 제3 및 제4절위에서 컸으며 절간중에 있어서는 제3 및 제4절위의 변이계수가 작았다. 그리고 각 절위간 경엽의 변이계수는 엽면적 8.90%로서 가장 적고 엽신중 11.24%로서 적은 편이었으며 간중은 20.02%로서 가장 컸다. 3. 수도의 엽간중에 대하여 엽신 엽초 및 절간이 각각의 고유하는 중량의 비율은 29.2%로서 가장 높고 간중 34.2%, 엽신중 26.6%로서 낮으며 각 절위에 있어서도 각 부분이 점유하는 비율은 대체로 같은 경향이지만 엽신중의 비중은 제2엽에서 크고 엽초중은 상위절에 갈수록 간중은 반대로 하위절일수록 비중이 높았다. 4. 4개절위를 합한 엽신/간비는 77.7%, 엽초/간비 114.5%, 엽신/엽초비 67.9% 및 엽신/간+엽초비 36.2%이며 상위벌에서 엽신/간비 및 엽초/간비는 높고 엽신/엽초비는 하위절에서 높았다. 5. 수도의 신장 절위 경엽과 수량과의 관계는 전체엽면적의 4개엽과 정조수량과의 상관관계(r)는 0.666이었고 제1엽 및 제2엽은 0.659 및 0.609로서 각각 고도의 정(+)의 상관을 보였으며 제3엽과 제4엽은 0.464, 0.523으로서 유의상관을 인정하였으며 전체엽신중과 정조수량간에는 0.678, 제1엽 0.691, 제2엽 0.654, 제3엽 0.570으로서 각각 고도의 정(+)의 상관을 보였고 제4엽에 있어서는 0.544로서 유의상관을 보였으며 엽중(엽신중+엽초중)과 수량과의 상관은 엽면적의 경우와 동일한 경향을 보였고 엽간중과 수량과의 상관은 총고간중 및 제1절위고간중에서만 고도의 정(+)상관을 보였고 그 밑에 절위에서는 유의상관을 보였다. 한편 전체엽초중과 정조수량간에 있어서는 0.572, 제1엽초 0.623으로서 각각 고도의 정(+)상관을 보였고 제2, 제3 및 제4엽초에 있어서는 각각 0.486, 0.513 및 0.450 으로서 유의상관을 보였고 간중과 정조수량과의 상관은 모두 0.377 이하로서 낮은 상관을 보였다. 6. 수량계급에 따르는 품종들의 신장 절위 경엽의 평균치로 본 엽신중, 엽면적 1 cm2 당 엽신중, 엽초중, 간중, 엽중은 모두 다수품종에서 컸으며 중수>소수품종의 순위로 낮았고 각 절위별에 있어서도 대체로 같은 경향을 보였으며 그들에 있어서의 절위간변이는 엽면적, 엽신중, 엽초중, 간중 모두 다수품종에서는 현저히 적고 중수 및 소수품종에서 컸다. 7. 수량계급에 따르는 품종들의 식물체지상부 구성비율 즉, 엽신, 엽초, 엽간이 각각 점유하는 비율은 다수품종에 있어서 엽신 27.6% 엽초 39.5%, 간 32.9%인데 비하여 소수품종은 엽신 25.5%, 엽초 38.1%, 간 36.4%이고 중수품종은 그들 중간적 값을 보였다. 8. 수량계급에 따르는 품종들의 엽신/간비, 엽초/간비는 다수품종은 높고 소수품종은 낮았으며 중수품종은 그들 중간을 보였다. II. 수도품종 신 2 호, 시로가네 및 진흥의 3개를 공시하여 10a당 실소를 8kg, 12kg 및 16kg의 3개수준으로 시용하여 신장 절위 경엽의 형태변이를 조사하는 한편 잎의 실소함량을 분석하여 그들과 수량과의 관계를 살펴 본 결과는 다음과 같다. 1. 신장 절위 경엽의 시용량에 따르는 3개 품종의 평균형태변이치는 총엽면적(선단으로부터 4개엽 총합)은 실소 8kg구에 비하여 2배비에서 16.5%의 증대를 보였으며, 총엽신중에 있어서도 거의 같은 비율의 증대를 각각 보였고, 총엽초중에 있어서는 2개비구 7.8%, 1.5 개비구 4.9%의 증대를 보였고, 각엽위별에 있어서도 전자와 비슷한 경향을 보였다. 한편 간중은 반대로 2개비구 11.2%, 1.5개비구 1.5%씩 각각 감소되었으며, 그 정도는 특히 하위절위에서 현저하였다. 2. 각 품종의 신장 절위 경엽이 시비량에 따르는 변이계수는 총엽면적에 있어서는 제002 15.40%, 시로가네 12.87% 및 진흥 10.99%였고, 각 절위별로 엽신의 변이가 큰 것은 신 002는 제4엽, 시로가네는 제2엽, 진흥은 제1엽으로서 품종간에 차이가 있었다. 총엽신중의 변이계수는 총엽면적의 경우와 같은 경향을 보였고, 총간중의 변이계수는 제002 7.72%, 시로가네 12.11% 및 진흥 0,94% 이였으며 각 절위별 변이의 정도도 품종에 따라 다르다. 3. 신장 절위 경엽의 시비량에 따르는 절위간 변이는 엽면적, 엽신중, 간중 모두 N8kg인 소비조건에서 변이가 크고 N16kg인 다비조건에서 적어졌으며 N12kg구는 이들 중간이고, 엽초중에 있어서는 다비조건에서 변이가 컸다. 4. 엽초중을 구성하는 엽신 엽초 및 절간이 각각 점유하는 비율은 시비량에 따라 다르며, 시비량의 증가에 따라 엽신중의 비율은 현저히 높아지고, 엽초중의 비율은 반대로 낮아진다. 5. 시비량에 따르는 공시품종의 신장 절위 경엽의 상호관계를 보면 엽신/간비는 소비구에서 낮고, 엽신/엽초비는 시비량의 증가에 따라 낮아지며, 엽초/간비는 높아지고 엽신/간십엽초중비율은 낮아졌다. 6. 시비량의 증가에 따라 공시품종 모두 신장절위의 엽면적, 엽신중, 엽초중은 증대되었다. 그에 따라 수량도 증가하는 경향을 보이고, 간중은 시비량 증가에 따라 감소되고 수량은 반대로 증대되는 경향을 보이는데 그 정도는 품종에 따라 차이가 있다. 7. 출수기 및 성숙기에 있어서의 잎의 실소함량은 시비량에 따라 다르며, 공시품종 평균실소함량은 출수기에 있어서 N8kg 시비구 2.74%, N12kg 시비구 2.49는 각구 0.80%, 0.92% 및 1.03%로서 증비에 의하여 실소함량이 현저히 증가되고 있으며, 엽위별에 있어서는 상위엽일수록 높았다. 8. 잎의 실소 함량은 품종간에 차이가 있는데, 동일품종내에서는 출수기와 성숙기에 있어서 그 함량이 높을수록 수량이 증대되였다.

Attempts were made to obtain the fundamental knowledge on the quantitative constitution status of leaves and stem of elongating node-part, and the relationships between these morphological characteristics along with the nitrogen contents of leaves and grain yield were examined varing application amounts of nitrogen in rice plant. I. The agronomic characteristics of leaves and nodes of elongation node-part (4-node parts from the top of stem) were observed at heading stage with 20 leading rice varieties of Kang Won district. The results are summarized as follows: 1. Leaf area magnitude of the flag and the fourth leaf was smaller than that of the second and the third with the average value of flag leaf 18.61 cm2 , the second leaf 21.84 cm2 , the third 21.52 cm2 and the fourth 18.56 cm2 . The weight of leaf blade showed an isotonic tendency with the magnitude of leaf area with the value of the flag leaf 97.0 mg, the second leaf 117.1 mg, the third 115.4 mg, and the fourth 95.3 mg. The weight of each leaf sheath was remarkably larger at the higher node-part than at the lower node-part of the stem with the value of flag leaf sheath 176.3 mg, the second 163.7 mg, the third 163.4 mg and the fourth 123.9 mg. Accordingly, the total leaf weight of each part was larger at the second and the third leaf than at the first and the fourth. Total plant weight of each part (weight of leaf blade, leaf sheath, and culm) also was larger at the middle node-part. 2. Coefficients of variation for the varietal differences of the morphological characteristics of elongating node-part were 12.75% for the leaf area, 15.29% for the weight of leaf blade, 15.90%, for the weight of leaf sheath, 11.42% for the weight of internode, 15.45% for the leaf weight (leaf blade ＆ leaf sheath) and 13.24% for the straw weight. And these coefficient values of the most characteristics were, on the whole, smaller at the second and the third node-part than at the first and the fourth node-part, but the coefficient value of the internode weight was rather small at the third and fourth node-part. 3. Constitutional ratio of each plant organ to the total plant weight in term of dry matter weight (excluding head and root wight) was 39.2% for the leaf sheath, 34.2% for the culm, 26.6% for the leaf blade. And ocnstitutional ratio of leaf sheath in term of dry matter weight was larger at the higher position in contrast with that of culm. 4. Average weight ration of leaf blade to culm, leaf sheath to culm, leaf blades to sheath and the leaf blades to culm plus leaf sheath were 77.7 %, 114.5%, 67.9% and 36.2%, respectively. With regard to the position of the plant organ, the weight ratio of leaf blade to culm and that of leaf sheath to culm were larger at higher part in contrast with that of leaf blade to leaf sheath. 5. Generally, there founded deep relationships between grain yield and each morphological characteristics of plant organ of elongating node-part as follows; Correlation coefficient between total area of 4 leaves (from flag to the fourth leaf) and grain yield was ~gamma =0.666** In regard to the position of leaves, correlation coefficient values of flag, the second, the third and the fourth leaf were ~gamma =0.659** , ~gamma =0.609** , ~gamma =0.464* and ~gamma =0.523* , respectively. Correlation coefficient between total weight of leaf blades and the grain yield was ~gamma =0.678** . In regard to the position of leaves, that of flag leaf was ~gamma =0.691** , and ~gamma =0.654** for the second leaf, ~gamma =0.570** for the third, and ~gamma =0.544** for the fourth. Correlation between the weight of leaves (blade weight plus sheath weight) and the grain yield showed similar values. In the relationship between plant weight and grain yield there also was significant correlation, but with highly significant value only for the first node-part. There appeared correlation between total weight of leaf sheath and grain yield with the value of ~gamma =0.572** and in regard to the position of each leaf sheath the values were ~gamma =0.623** for the flag leaf, ~gamma =0.486** for the second leaf, ~gamma =0.513** for the third, ~gamma =0.450** for the fourth. However, there was no significant correlation between culm weight and grain yield. 6. With respect to in gain yield, varietal differences in magnitude of leaf area, weight of leaf blade, leaf weight per unit area, weight of leaf sheath, culm weight, total leaf and stem weight were larger in the case of high yielding varieties and decreased in accordance with decreasing yield. And this tendency also was shown in the varietal differences of magnitude of each part. Variation in magnitude of each part for the leaf area, weight of leaf blade, culm weight was significantly small in high yielding varieties compared to low yielding varieties. 7. Plant constitutional ratio of each organ of the elongating node-part in term of weight magnitnde varied to som extent according to varieties indicating leaf blade 27.6%, leaf sheath 39.5%, culm 32.9% in the case of high yielding varieties, leaf blade 25.5%, leaf sheath 38.1%, culm 36.4% in the case of low yielding varieties, and medium yielding varieties showed intermadiate values. 8. Far higher values of the weight ration of leaf blade to culm and leaf sheath to culm were given to the high yielding varieties compared to low yielding varieties. And medium yielding varieties showed intermadiate values. II. Effects of application rate of nitrogen on the morphological characteristics of the elongating node-part, nitrogen content of leaf blade, and their relation with the grain yield of the rice were observed with 3 rice varieties; Shin No.2, Shirogane, and Jinheung varying application amounts of nitrogen as 8kg, 12kg and 16kg per 10 are. 1. As for the variation of morphological magnitude s affected by the amounts of nitrogen application, total leaf area (4 leaves from the flag leaf) increased to 16.5% at 12kg N plot, and about 30% at 16kg N polt compared to 8kg N plot and total weight of leaf blade also increased to similar extent, respectively, in contrast with weight of leaf sheath increasing 4.9% and 7.8%, respectively. However, the weight of culm decreased to 1.5% and 11.2%at the 12kg N plot and 16kg N plot, respectively, and these decreasing rate was noted at the nodes of lower part. 2. As for the verietal differences in variation of morphological magnitude as affected by the amount of nitrogen fertilization, leaf area coefficient value of variation of the total leaf area was 15.40% for Shin No. 2, 12.87% for Shirogane, and 10.99% for Jinheung. With respect to the position of nodes, the largest variation of leaf blade magnitude was observed at the fourth for Shin No. 2, the second for Shirogan, and flag leaf for Jinheung. And there also was an isotonic varietal difference in the weight of leaf blade. Variation in total culm weight showed varietal differences with the coefficient value of 7.72% for Shin No.2, 12.11% for Shirogane, and 0.94% for Jinheung. There also was varietal differences in the variation according to the position of nodes. 3. Variation of each elongating node-part related to the fertilization amount decreased with the increase of fertilization amount in the items of leaf area, weight of leaf sheath, culm weight, but weight of leaf sheath varied more at heavier fertilization than at others. 4. Constitutional ratio of each organ excluding head also varied with fertilization amount; constitutional ratio of leaf blade increased much with the increasing amount of fertilization in contrast with the response of culm eight. However, constitutional ration of the weight of leaf sheath was not much affected. 5. Lower value of the ration of leaf blade to culm was given to the 8kg N per 10 are plot, and the ratio of leaf blade to leaf sheath decreased with the increasing amount of fertilization in contrast with the increase in the ratio of leaf sheath to culm. however, the ration of leaf blade to culm plus leaf sheath decreased. 6. With the increase of nitrogen fertilization, leaf area, weight of leaf blade and leaf sheath increased. Accordingly, grin yield also increased to some extent. It was noted that culm weight was changed inversely to the changes in grain yield, but the degree of this variation varied with varietal characteristics. 7. Nitrogen content of leaves at heading and fruiting stage varied with the fertilization amount, and average nitrogen content of leaves of the varieties used 2.19%, 2.49% and 2.74% at the plot of 8kg N, and 12kg N and 16kg N per 10 are, respectively, at heading time, and 0.80%, 0.92% and 1.03% at each plot at fruiting stage. Thus, nitrogen content of leaves increased much with the increasing amount of fertilization, and higher value was given to the leaves on the higher position of elongating node-part. 8. There also was variation of nitrogen content of leaves in accordance with the varieties. However higher grain yield was obtained from the plants retaining higher nitrogen content in leaves at heading or fruiting stage.

• 金萬壽(강원도농촌진흥원) | 김만수