1. Alfalfa의 조단백질(粗蛋白質)은 채취시기가 경과함에 따라 1회(回) 19.64%에서 4회(回) 12.37%로 낮아졌으며, 조섬유, CWC, Cellulose도 낮아지는 경향을 보였다. Orchard grass도 조단백질(粗蛋白質)은 1회(回) 13.79%에서 2,3회(回) 12.97, 12.85%로 낮아졌으며 4회(回) 14.72%로 다소 상승하였다. 그밖에 조섬유, CWC는 채취시기가 진행됨에 따라 낮아졌으며 Cellulose는 시기에 다소

alfalfa 단파초지(單播草地)에 있어서 최대총건물(最大總乾物) 생산(生産)과 질적(質的) 향상(向上)을 위한 예취적기(刈取適期)가 연구(硏究)되었다. 최대총생산수량(最大總生産收量)을 위한 예취기(刈取期) tc(장(張), 1971)가 alfalfa 초종(草種)의 영속성(永續性)과 동시에 CP 및 IVD의 높은 수준(水準)을 수분하는 최대건물생산수량(最大乾物生産收量)의 적기(適期)로 선택(選擇)되었다. 이와 동일(同一)한 이론적(理論的) 근거에 입각하여

Soil conservation management is necessary for sustainable agriculture, in highland areas, and cover crops are one of the best soil conservation methods for slopes. In this study, we evaluated the effects of alfalfa cultivation on maize production, as well as soil conservation and quality. There was an outstanding soil conservation effect with alfalfa cultivation in the fallow and maize growing seasons. In particular, alfalfa cultivation reduced soil loss by up to 98% compared with bare field. It also increased the activities of soil microorganisms and the supply of organic matter. Maize production with alfalfa cultivation showed no significant differences in yield. In conclusion, alfalfa is an advantageous perennial cover crop in highland agricultural slope areas, which can have positive effects on soil quality and conservation, as well as maize production.

To develop transgenic forage crops with enhanced tolerance to abiotic stress, we introduced an alfalfa Hsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by PCR, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. The reduced accumulation of thiobarbituric acid reactive substances indicates that the transgenic plants possessed a more efficient reactive oxygen species-scavenging system. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic forage crops and may be useful in developing stress tolerance in other crops.

Alfalfa (Medicago sativa L.) is one of the most important forage crops in the world and it’s has been known as the best feed materials for dairy cows and other high valued animals. The new uses of alfalfa are being explored as bio-energy, food, medical and biochemical uses. R2R3-type MYB transcription factors play important roles in transcriptional regulation of anthocyanin biosynthesis. The R2R3-type IbMYB1 is known to be a key regulator of anthocyanin biosynthesis in the storage roots of sweetpotato. We previously showed that the expression of IbMYB1a led to anthocyanin pigmentation in tobacco and Arabidopsis. In this study, we generated transgenic alfalfa plants expressing the IbMYB1a gene under the control of CaMV 35S promoter. Overexpression of IbMYBa in transgenic alfalfa produced strong anthocyanin pigmentation in seedlings and generated a deep purple color in leaves, stems, roots, and even in seeds. High performance liquid chromatography (HPLC) analysis revealed that IbMYB1a expression led to the production of cyanidin as a major core molecule of anthocyanidins in alfalfa, as occurs in the purple leaves of sweetpotato (cv.Sinzami). We also examined expression of several structural genes in the anthocyanin biosynthetic pathway in alfalfa by RT-PCR analysis. In this presentation, we will further present molecular and biochemical characterization in IbMYB1a-overexpression lines. This result shows that the IbMYB1a transcription factor is sufficient to induce anthocyanin accumulation in the forage legume alfalfa plants.

The molecular responses to various abiotic stresses were investigated by the approaches with transcriptomic analysis based on an ACP system. Here we identified differentially expressed genes under abiotic stresses in alfalfa seedlings and they were mostly unknown genes and a few common stress-related genes. Among them, mitochondrial small HSP23 was responded by the diverse stress treatment such as heat, salt, As stresses and thus it could be a strong candidate that may confer the abiotic stress tolerance to plants. When expressed in bacteria, recombinant MsHSP23 conferred tolerance to salinity and arsenic stress. Furthermore, MsHSP23 was cloned in a plant expressing vector and transformed into tobacco, a eukaryotic model organism. The transgenic plants exhibited enhanced tolerance to salinity and arsenic stress under ex vitro conditions. In comparison to wild type plants, the transgenic plants exhibited significantly lower electrolyte leakage. Moreover, the transgenic plants had superior germination rates when placed on medium containing arsenic. Taken together, these overexpression results imply that MsHSP23 plays an important role in salinity and arsenic stress tolerance in transgenic tobacco. The results of the present study show that overexpression of alfalfa mitochondrial MsHSP23 in both eukaryotic and prokaryotic model systems confers enhanced tolerance to salt and arsenic stress. This indicates that MsHSP23 could be used potentially for the development of stress tolerant transgenic crops, such as forages.

Tall fescue (Festuca arundinacea Schreb.) is an important cool season forage plant that is not well suited to extreme heat, salts, or heavy metals. To develop transgenic tall fescue plants with enhanced tolerance to abiotic stress, we introduced a MsHsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by PCR, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic tall fescue and may be useful in developing stress tolerance in other crops. Compared with traditional plant breeding, genetic engineering provides a relatively fast and precise means of achieving improved stress tolerance of forage crops. Development of forage crops that are more tolerant to various abiotic stresses could lead to the use of more new lands for cultivation.

Compositae plants are known to contain biologically active substances that are allelopathic to agricultural crops as well as weed species. Aqueous extracts from leaves of Xanthium occidentale were assayed against alfalfa (Medicago sativa) to determine their allelopathic effects, and the result showed that the extracts applied onto filter paper significantly inhibited seed germination as well as root growth of alfalfa. Untreated seeds germinated in 60h, but extract concentrations greater than 30g ~textrmL-1 delayed seed germination. The extracts significantly inhibited seed germination of alfalfa, and β -amylase activity of alfalfa and barley seeds during 24-36 hours after treatment. Aqueous extracts of 40 g ~textrmL-1 from X. occidentale were completely inhibited the hypocotyl and root growth of alfalfa. Aqueous leaf extracts showed the highest inhibitory effect and followed by root and stem extracts. Early seedling growth of both alfalfa and barnyard grass (Echinochloa crus-galli) was significantly reduced by methanol extracts. By means of high-performance liquid chromatography, chlorogenic acid and trans-cinnamic acid were quantified as the highest amounts from water and EtOAc fractions, respectively. BuOH and EtOAc fractions of X. occidentale reduced alfalfa root growth more than did hexane and water fractions. The findings of the bioassays for aqueous or methanol extracts reflected that the inhibitory effect of extract was closely related to the level of responsible allelochemicals found in plant extracts.

Alfalfa (Medicago sativa L.) plants have been reported to be autotoxic as well as allelopathic. Laboratory and greenhouse experiments through petri-dish and pot test were conducted to determine autotoxic effects of alfalfa leaf and soil extracts on the germination or early seedling growth of alfalfa, and to evaluate allelopathic effects of alfalfa leaf residues on alfalfa, barnyard grass, com, eclipta and soybean. Alfalfa seed germination was delayed depending on aqueous extract concentration, with no difference in final germination after 48 hours. Alfalfa root length was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Root growth of alfalfa was significantly inhibited at extract concentration of more than 1 g dry tissue/L (g ~textrmL-1 ). Hypocotyl growth, however, was not affected by all the concentrations of leaf extracts. Soil extracts from 4-yr-old alfalfa stand significantly reduced alfalfa root length by 66%, while soil extracts from 0,1, and 3yr-old stand stimulated root length up to 14-32% over the control. Residue incorporation with dry matters of alfalfa leaf at 100 g ~textrmkg-1 reduced seedling length of several crop and weed species, ranging from 53 to 87% inhibition. Addition of nutrient solution into alfalfa leaf extracts alleviated alfalfa autotoxic effect. This result indicates alfalfa leaf and soil extracts or residues could exert autotoxic as well as allelopathic substances into soil environments during and after establishment.

Alfalfa (Medicago sativa L.) plants have been reported to contain water-soluble substances that are autotoxic as well as allelopathic. Laboratory experiment through a petri-dish assay with imbibed seeds was conducted to evaluate both autotoxic and allelopathic effects of alfalfa leaf extracts on the germination and early seedling growth of alfalfa, red clover, crested wheatgrass, and Russian wildrye. Alfalfa seed germination was delayed dependent on extract concentration, with no difference in final germination at 72 hours. Root growth of alfalfa was stimulated up to 14% above control at very low concentrations of both leaf and stem extracts of alfalfa and was significantly reduced at extract concentration of more than 0.5g dry tissue/L (gL-1 ). Leaf extracts were generally more autotoxic for root growth than were stem extracts. Hypocotyl growth was not affected by all the concentrations of both leaf and stem extracts. Root length of legumes was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Hypocotyl growth of two legume plants and plant height of two grasses were not influenced by extracts. Seed germination and root growth of legumes were more inhibited by aqueous extracts of alfalfa leaf than were those of grasses. This result indicates autotoxic effect of alfalfa leaf extracts seems to be greater than allelopathic effect.

Most parts of alfalfa plant have been reported to contain autotoxic substances that inhibit seed germination and early seedling growth, however, the chemical(s) is not still studied much. Effect of seed leachates of 'Vernal' alfalfa (Medicago sativa L.) was evaluated for inhibition of alfalfa germination and root growth through bioassay. Alfalfa seeds were extracted in 1 L deionized water for 1 h after soaking and the leachates caused to reduce root length of alfalfa significantly as the soaking time increased. Crude seeds at 4 g LL-1 exudated autotoxins that reduce significantly root length by 34 % compared to the control, when the seeds soaked in deionized water for 24 h. However, the extracts did not affect final germination as well as speed of germination. Extracts from ground seeds significantly reduced speed of germination (GT 50) and root length. The results indicate that release of autotoxic substances from seeds during seed imbibition was increased with increase of soaking time and seed amount, and that autotoxicity was more occurred in ground seeds than in crude seeds.

Autotoxicity restricts reseeding of new alfalfa(Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments, often requiring up to a year or more. One solution for reducing autotoxicity would be to select germplasms or cultivars with tolerance to the autotoxic chemical(5) and use genetically breeding program. Bioassay of seed germination and early seedling growth was conducted to evaluate autotoxic responses of 3 varieties of alfalfa to the water-soluble extracts(at 4 and 8g/L) from alfalfa ‘Cody’leaf by using agar and filter paper medium in a petri-dish assay. Root length at 5 days after seeding was more sensitive to the extract than was hypocotyl length or seed germination, and was a better parameter of autotoxic effects of alfalfa leaf extracts. Use of an agar medium gave better sensitivity of root length than did use of filter paper. Evaluating tolerance with percent of control was more important indicator than was mean of root length because of significant variation among varieties in root length of control treatment. Bioassay ranked varieties in the following order of tolerance on the basis of relative root length; “Cody” >“ Pioneer 5373” >“ Alfagraze”. Seedling growth from old “Cody” seed was more sensitive to the autotoxic chemical(5) than was that from newly produced seed.

본 실험은 알파파 꽃 추출물로부터 Allelopathy와 Autotoxicity에 관련되는 활성물질을 분리, 동정하기 위하여 실시하였다. 알팔파 꽃 200g을 80% MeOH로 추출하여 CHCl3 층을 silica gel thin layer chromatography (TLC), microcrystalline cellulose thin layer chromatography (MCTLC)와 droplet countercurrent chromatography(DCCC)의 분획을 이용하여 생물검정을 행하고 DCCC의 생물검정에서 가장 억제력을 보였던 분획 5와 6은 HPLC로 활성물질을 동정하였다. HPLC분석 결과 분획 5에서는 ferulic acid, caffeic acid, vanillic acid, rutin, narringin 이, 분획 6에서는 ferulic acid, caffeic acid, vanillic acid, rutin, coumarin이 동정되었다. 이들 동정된 물질을 이용한 알팔파와 돌피에 대한 발아실험에서도 모두 알팔파와 돌피의 발아와 생육에 억제적으로 작용하였으며, 이중 coumarin의 처리가 가장 억제적이었다. 따라서 이들 물질이 알팔파와 돌피의 autotoxicity와 allelopathy에 관련하는 것으로 생각되었다.

알팔파 종자와 재배지 토양의 추출물이 알팔파 및 무우의 발아 및 생육에 미치는 영향과 이들 물질을 구명코자 수행한 결과를 요약하면 다음과 같다. 1) 알팔파 종자 추출물의 무우생육에는 Luna, Sparta, Magnum, Husky, Milkmaker, Challenger, Anchor의 7개 품종에서 60∼80％ 생육억제 효과를 보였다. 2) 알팔파 재배지 토양잔류추출물을 이용한 무우생육조사는 추출물의 농도가 증가하면서 발아억제 및 줄기, 뿌리 등의 생장억제에 관여하는 것으로 나타났다. 3) 알팔파 재배토양으로 알팔파와 무우 생육실험시에는 80％의 발아억제를 보이면서 줄기와 뿌리의 길이 및 생체중에서도 큰 차이를 보여 allelopathy와 autotoxicity가 관여하는 것으로 사료된다. 4) 위 실험을 통해 관여하는 물질의 활성을 분석하기 위해 조사한 결과 표준 phenol compounds와 식물부위별 추출물을 비교 분석하였더니 salicylic acid, p-hydroxybenzoic acid, vanillic acid, syringic acid, p-cou-maric acid, ferulic acid 등의 7가지 acids를 분리동정 할 수 있었다.

알팔파 (Medicago sativa L.)의 예취후 재생 기간중 저장탄수화물의 이용성을 규명하기 위해 수경재배하여 개화초기에 예취한 후 재생 24일간의 뿌리내 비구조탄수화물의 함량 및 전분 분해효소의 활력을 분석한 결과는 아래와 같다. 1. 재생초기 10일간의 잎과 줄기의 재생은 매우 느리게 진행되었으며, 예취후 뿌리의 성장이 억제되었다. 2. 예취후 초기재생 10∼14일간 뿌리내 가용성 당 및 전분의 함량은 다같이 감소하였다가 이후 빠르게 회복하는 경향이었다. 3. 재생기간중 exo-amylase의 평균 활력은endo-amylase에 비해 약 400배 이상 높았다. Exo-amylase의 활력은 재생 6일차(최고수준) 까지 증가하다가 이후 감소하였다. Endo-amylase의 활력은 재생초기 4일 동안 급격히 증가하다가 이후 재생 24일차(최고수준) 까지 서서히 증가하는 경향이었다. 이상의 결과들은 알팔파의 재생초기 동안 전분 분해효소의 활력의 증가와 아울러 뿌리내 저장탄수화물은 활발히 분해되어 새로운 조직의 재생에 이 용됨을 간접적으로 제시한다.

본 실험은 온실과 포장에서 재배한 알팔파를 잎, 줄기, 뿌리, 꽃 부분으로 나누어 수확, 건조,하여 물 추출한 후 이 추출물들이 알팔파 발아와 생육에 미치는 영향을 조사 비교하였으며 포장상태에서 자란 알팔파 지상부 전체를 수확,건조, 추출하여 이를 농도별로 처리 알팔파 발아율을 검정하였고, pot실험을 통하여 알팔파 품종간 biomass 분배율 검정과, 알팔파 autotoxicity를 해결하기 위한 방법으로 추출물을 adsorbent로 처리하여 이들이 알팔파 독성성분을 변형시키는지를 검토하였다. 1. 온실과 포장에서 자란 알팔파의 추출물로 알팔파 발아 및 생육에 대한 영향을 비교한 결과 포장에서 자란 추출물질이 발아와 생육에 더 억제적으로 작용하였고, 특히 포장에서 생육한 꽃 추출물 처리가 가장 억제적으로 작용하였다. 2. 농도처리에 따르는 추출물 처리는 농도가 증가 할수록 발아율이 억제되었고, biomass분배율에 대한 pot실험에서는 LWR 과 SLA의 산물인 LAR은 품종간 유의성을 보였다. 3. 알팔파 추출물에 대한 absorbents처리는 추출물의 독성을 변형시키지 못하였다.