• Journal of The Korean Society of Grassland and Forage Science
• /
• v.9 no.1
• /
• pp.20-25
• /
• 1989

This experiment was carried out in order to know the decreasing causes of plant density and its relations with pasture productivity by the times of established pasture. The results were summarized as follows, 1. The yield components of dead plant can be used to estimate the changes of pasture productivity by the times of established pasture. 2 . The number of dead plants(PD) showed a quadraticalrelation with mean dry weight of dead plant $W/pl.)$ by the times of established pasture. 3. Relationship between relative number of tillers per dead plant to mean number of tillers of adjacent plants (RNT) and relative ratio of number of tillers per dead plant to number of tillers of plants in the 1st cutting (RNDT) showed highly positive significant correlation in 1 and 3 years old pasture. 4. Less than 100 of RNT were 79.5 %, 71.4 % and 100 % of dead plants in 1, 3 and 5, and 7 years old pasture, respectively. 5. Not exceeding values of RNDT to MRRNT were 89.7 %, 71.4 % and 100 % of dead plants in 1, 3 and 5, and 7 years old pasture. 6 . The values of 79.5 %, 57.2 % and 100 % of dead plants in 1, 3 and 5, and 7 years old pasture were not exceeding to MRRNT and less than 100 of RNT. 7. From the results described above, it was discussed that the relative number of tillers per dead plant(RNT) should be described not absolute deaeasing causes of plant density in 1 and 3 yars old pasture. But, the total number of dead plants in 5 and 7 years old pasture were absolutely influenced by RNT and MRRNT.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.17 no.4
• /
• pp.351-356
• /
• 1997

With a purpose of finding out the influences of herbicide treatment on the forage value and ecological characteristics of grassland vegetations in the Rumex acetosella dominated pasture, this trial was arranged as a randomized block design with three treatments[1) Seeding(cntrol), 2)dicamba 4${\ell}$/ha+seeding+dicamba 4 ${\ell}$/ha and 3) dicamba 4${\ell}$/ha+lime+seeding+dicamba 4 ${\ell}$/ha], and conducted in Youngam, Jeonnam Province ftom June, 1995 to October, 1996. In the Rumex acetosella dominated pasture, the treatment of dicamba 4${\ell}$/ha+ lime+seeding+dicamba 4${\ell}$/ha was improved to the most desirable grassland vegetation with pasture plants of 87%. In the renovated grassland, the life forms of Hemicryptophytes increased greatly by 57.0%, on the other hand Geophytes was much more decreased by 56.8% than those of low productive grassland. The similarity coefficients between grassland vegetation groups were greatly affected by botanical composition. The forage value of standing crop in the renovated grassland with 6.56 was much more increased than low productive grassland with 2.76. The treatment of dicamba 4${\ell}$/ha+lime+ seedingdicamba 4${\ell}$/ha increased 2 1% of dry mattaer yield, and were high 18- 19% of energy (NEL and TDN) productivity than those of the control(seeding), respectively.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.11 no.4
• /
• pp.199-202
• /
• 1991

The esterase isozyme of several legume plants were separated and visualized by horizontal starch gel electrophoresis using enzyme-specific staining. Extracts used were prepared from fully expanded young leaf and stem of six legume species which were red clover(Trifolium Pretense L.), ladino clover(Trifolium repense L.), wild white clover(Trifolium repense L.), alfalfa(Medicage sativa L.), mimosoides(Cassia mimosoides var nomame Makino), and amoena(Vicia amoena Fisch). The number of band, Phenotype and staining intensity of esterase isozyme in leaf and stem varies depending on the plant species. However, there are little difference between leaf and stem esterase isozyme in same species except alfalfa. And in the leaf and stem of mimosoides and amoena showed not any esterase(Fig. 2). Among the examined plants, the highest staining intensity and the rapidest migrating esterase isozyme was Est 1.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.8 no.1
• /
• pp.26-32
• /
• 1988

This study was conducted to determine the effects of cutting frequency and cutting height on agronomic characteristics and yield performance of sorghum-sudangrass hybrid, cv. Pioneer 855 F on the experimental field of Livestock Experiment Station, Suweon. The results are summarized as follows: 1. The relative contribution of leaf component to total yield was higher when the plants were cut frequently rather than when defoliated only a few times, and tend to be higher with high cutting. 2. Leaf Area Index (LAI) was the highest at the primary growth of two cutting times scheme and the first regrowth for three or four cutting times a year, but LAI, in general, was not related to cutting height. 3. Crop Growth Rate was the heighest at the first regrowth-plants grown in summer, and it was also related to the amount of stubble left at the previous cut. 4. Dead stubbles were not occurred when plants were cut before heading, but those were accompanied by the frequent and low cutting. 5. Total fresh fodder and dry matter yield were the highest at two times cut a year, and decreased with frequent cutting. The optimum cutting height at two times cut was ca. lOCm height stubble from the ground level, but yield increased with higher level cutting at the three or four times cut a year.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.20 no.2
• /
• pp.77-84
• /
• 2000

Eight-week old perennial ryegrass (Lolium perenne L. cv. Reveille) plants were exposed to different NO3-concentrations or osmotic stress with NaCI. Previously labeled "N was chased during 14 days of non-labeled'NO3 feeding in order to investigate NO3 metabolism in relation to osmoregulation. The short termmeasurement of osmotic potential showed that the extemal concentration of Nos- had not great effect on theosmotic potential, but that osmotic adjustment was observed in NaCl-treated plants. Total uptake of NO 3 - waslargely increased by increasing supply level of NO3 while it was depressed by exposing to osmotic stress.Nitrate reduction increased to more than 29% by increasing extemal NO,- concentration from 1 mM to 10mM. When osmotically stressed with NaCI, nitrate reduction was depressed to about 37% as compared to thecontrol. The decrease in translocation of reduced N into leaves was also observed in NaCl exposed plants. Inthe medium exposed to 10 mM NO,., osmotic contribution of nitrate to cumulative osmotic potential wasdecreased, and it was osmotically compensated with soluble carbohydrate. When osmotically stressed withNaC1, the contribution of chloride was much higher than that of nitrate. The present data indicate that N03-in plant tissues, factually affected by the assimilation of this ion, plays an active role in osmotic regulation incorrelation with other osmotica such carbohydrate and chloride.(Key words : Nitrate metabolism, Osmotic stress, Nitrate supply level, Osmoregulation)ate supply level, Osmoregulation)

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.38 no.3
• /
• pp.170-174
• /
• 2018

Environmental stresses caused by climate change, such as high temperature, drought and salinity severely impact plant growth and productivity. Among these factors, high temperature stress will become more severe during summer. In this study, we examined physiological and molecular responses of maize plants to high temperature stress during summer. Highest level of $H_2O_2$ was observed in maize leaves collected July 26 compared with June 25 and July 12. Results indicated that high temperature stress triggers production of reactive oxygen species (ROS) in maize leaves. In addition, photosynthetic efficiency (Fv/Fm) sharply decreased in leaves with increasing air temperatures during the day in the field. RT-PCR analysis of maize plants exposed to high temperatures of during the day in field revealed increased accumulation of mitochondrial and chloroplastic small heat shock protein (HSP) transcripts. Results demonstrate that Fv/Fm values and organelle-localized small HSP gene could be used as physiological and molecular indicators of plants impacted by environmental stresses.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.6
• /
• pp.908-913
• /
• 2007

Concentrations of major elements in forages were determined in relation to ruminant requirements at a livestock experimental station in Leiah district, Punjab-Pakistan using mapping techniques. The study investigated the influence of sampling periods and pasture types on the concentrations of calcium, magnesium, potassium, and sodium in forages. The implications of these forages for nutrition of ruminants were assessed for the livestock population at that particular experimental station, which are supported by the farm pastures. Within the farm, variations in the element status of the forages were related to soil pasture types. A tentative assessment of the mineral status of available forages at this farm for different pastures using guidelines developed for domestic animals indicated deficiencies of only Na, but forages contained adequate Ca, Mg, and K levels required for grazing ruminants. The concentrations of Na in the forage reserves indicated that the potential supply of this element to plants was limited from the soil to plants and from plants to the animals grazing them. Soil minerals were not measured in this study. The potential use of fertilizers, as pasture amendment as well as supplementation of ruminants, with a specifically tailored mineral mixture is important to livestock producers and environmentalists as well, because their use may improve forage nutritive value and in turn meet requirements of animals.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.7 no.3
• /
• pp.140-145
• /
• 1987

In 1985 and 1986, silage productivity of 8 Korean improved and 7 US introduced corn hybrids and their resistance to rice black-streaked dwarf virus (RBSDV) were tested in the southern part of Korea where RBSDV is prevalent. The results obtained are summarized as followes: 1. Percentage of RBSDV diseased plantes differed depending on the year and hybrid. Suweon 19, Kwangok, Hoengseungok, Jecheonok, Pioneer 3424, Pioneer 3H001, NC6 13 1 were most susceptible, Pioneer 3 160 and Pioneer 3358 were moderately susceptible, and Nampyungok, Suweon 90, Pioneer XCF38, PB 2, and Jinjuok were least suceptible. No hybrid was completely resistant to RBSDV. 2. There were negative correlations between percentage of RBSDV diseased plants and culm length, percentage of ear bearing plants, ear yield, silage yield, or digestible dry matter, but percentage of RBSDV diseased plants was not correlated with stover yield. 3. Silage yield of Jinjuok, Pioneer 3160, Pioneer 3358, and Pioneer XCF38 were higher than that of other hybrids in both years. However, digestible dry matter of Nampyungok, Suweon 89, and Suweon 90 were higher than that of other hybrids due to a higher proportion of ear in 1986 when RBSDV infection was severer.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.18 no.1
• /
• pp.69-76
• /
• 1998

This study was conducted to construct of the transgenic plants wliich are resistant to oxidative stresses including ozone with B. mpestris cytosolic glutathione reductase cDNA using the binary vector system of Agrobacterium tumefaciens. The 1.8kb B. campestris cytosolic GR cDNA was subcloned into the unique Sma I site of the plant transformation vector pBKSI- I, downstream of the constitutive CaMV 35s promoter and upstream of the nos termination sequence, in place of the uidA (GUS) reporter gene. The resulting plant transformation vector, pBKS-GRI, was introduced into A. tumefaciens LBA4404 by two cycles of tkeze-thaw method. The B. nqus cotyledonary petioles were transformed by the Agrubaferium harboring pBKS-GRI. Transformed shoots were induced and selected on regeneration medium supplemented with kanarnycin. The shoot formation was increased remarkably by addition of Ag$NO_3$, in MS media. The transgenic plants were analyzed for the presence of the B. campestris GR gene by Southern blot analysis and it was confirmed that a foregin gene was stably integrated into the genomes of B. nqus plants.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.1 no.1
• /
• pp.10-17
• /
• 1978

The experiment were carried out to determine the rate of regrowth, the changes of carbohydrates contained in the samples right after cutting, plant part for storage of carbohydtates and top-dressing time of ladino clover and orchardgrass. Plants were grown in the simple growth chamber as well as in the fields. The temperature, light intensity and light period were controlled to be 15-20$^{\circ}$, 4,250 Lux, and 15 hours in the simple growth chamber. The results obtained are as follows ; 1. The period of recovery to initial stands after cutting was about 3 weeks in ladino clover and 4-5 weeks in orchard grass in terms of dry matter and carbohydrates. 2. The content of total water-soluble carbohydrates of plant parts was the hightest in stolon of ladino clover and in sheath of orchardgrass, and the lowest in roots of ladino clover and orchardgrass. 3. Cutting resulted in a temporary decrease of total water-soluble carbohydrates in the shoots. Similar trends were observed when the plants were left intact with top-dressing. 4. The top-dressing applied simultalliousely with the cutting was more effective to stimu1ate regrowth than that applied after cutting, however, both of the simultaneous and after cutting application were still better than application prior to cutting.