Ammonium (NH4 +) serves as a nitrogen source, but its elevated levels can hinder plant growth and production. Excess NH4 + with α-ketoglutarate is assimilated into glutamate, a precursor of proline and glutathione (GSH). This study aimed to investigate the effects of excessive NH4 + on the regulation of proline and GSH synthesis. Detached leaves from oilseed rape (Brassica napus L.) were fed with 0, 50, 100, 500, and 1000 mM NH4Cl for 16 h. As the NH4 + concentrations increased, the leaves exhibited progressive wilting and yellowing. Furthermore, total carotenoid and chlorophyll concentrations declined in response to all NH4 + treatments, with the lowest levels observed in 1000 mM NH4 + treatment. Hydrogen peroxide (H2O2) concentration showed a minor increase at low NH4 + concentration (50 and 100 mM) treatments but a significant increase at high NH4 + (500 and 1000 mM), which was consistent with the localization of H2O2. Amino acid concentrations increased with increasing in NH4 + concentration, while the protein concentration displayed the opposite trend. Proline and cysteine concentrations exhibited a gradual increase in response to increasing NH4 + concentrations. However, GSH concentrations rose only in the 50 mM NH4 + treatment and decreased in the 500 and 1000 mM NH4 + treatments. These results indicate that excessive NH4 + is primarily assimilated into proline, while GSH synthesis is adversely affected.

The germination process is critical for plant growth and development and it is largely affected by environmental stress, especially salinity. Recently, hydrogen sulfide (H2S) is well known to act as a signaling molecule in a defense mechanism against stress conditions but poorly understood regulating seed germination. In this study, the effects of NaHS (the H2S donor) pretreatment on various biochemical (hydrogen peroxide (H2O2) content and amylase and protease activity) and physiological properties (germination rate) during seed germination of oilseed rape (Brassica napus L. cv. Mosa) were examined under salt stress. The seed germination and seedling growth of oilseed rape were inhibited by NaCl treatment but it was alleviated by NaHS pretreatment. The NaCl treatment increased H2O2 content leading to oxidative stress, but NaHS pre-treatments maintained much lower levels of H2O2 in germinating seeds under salt stress. Amylase activity, a starch degradation enzyme, significantly increased over 2-fold in control, NaHS pretreatment, and NaHS pretreatment under NaCl during seed germination compared to NaCl treatment. Protease activity was highly induced in NaHS-pretreated seeds compared to NaCl treatment, accompanied by a decrease in protein content. These results indicate that NaHS pretreatment could improve seed germination under salt stress conditions by decreasing H2O2 accumulation and activating the degradation of protein and starch to support seedling growth.

Oilseed rape is known to crop having low nitrogen use efficiency (NUE) but requires high levels of N fertilizer. NUE is associated with N remobilization from source to sink organ, consequently affects seed yield. Remobilization of leaf N is also related to transport of C/N metabolites in phloem. However, interaction between seed yield and phloem transport was not fully documented. In response to seed yield, N and C metabolites and their transport into seed from bolting to pod filling stage investigated in two contrasting genotypes (Capitol and Pollen) cultivated under ample (HN) or limiting nitrate (LN) supply. Seed yield was significantly reduced in N limitation and its reduction rate was much lower in Capitol than in Pollen compared to HN treated plants. Amino acid and protein content was higher in Capitol than in Pollen at bolting stage. They gradually decreased during plant development but not significant between two cultivars and/or two treatments. Glucose, fructose and sucrose content were 1.8-,1.6- or 1.25-fold higher in LN condition than in HN condition, respectively. Amino acid and sucrose content in phloem were largely higher in Capitol than in Pollen under LN condition. These results indicate that the higher seed yield might be related to greater transport ability of amino acid and sucrose in phloem under LN condition.

유채 품종에서 황 공급수준이 황산염 흡수 및 동화에 미치는 영향을 구명하고자 어린 잎과 성엽조직에서 ATP sulfurylase (ATPs), SO42－ 흡수, 글루타치온 함량을 분석하였다. 본 실험에서 10가지 유채 품종들 (Mosa, Capitol, Saturnin, Akela, Pollen, Mokpo, Youngsan, Tamra Colosse 그리고 Naehan)은황 공급수준에 따라 몇 가지 황산염 흡수와 동화 능력이 다르게 나타났다. 황 결핍 조건에서 모든 품종의 ATP sulfurylase (ATPs) 활력은 늙은 잎에 비해 어린 잎에서 높게 나타났으며, 글루타치온 함량은황 공급수준이 감소함에 따라 어린 잎에서 많이 증가하였다. 이러한 결과들은 유채 품종별 황 결핍조건에서 황을 이용하는 능력이 다르다는 것을 잘 보여주었다.

This experiment was conducted to evaluate the effect of temperature rise on the phenological development and yield of oilseed rape in temperature-controlled plastic houses located at Suwon in 2008 and 2009. Two varieties "Halla" and "Naehan" were grown using 1/5000a Wagner pots in the three plastic houses greenhouses in which temperature was controlled to ambient temperature (AT), AT+1.5℃, and AT+3.0 through the growing season. Compared to the ambient temperature, leaf appearance was speeded up by temperature elevation, resulting in earlier flowering by 7 and 19 days at the treatments of AT+1.5℃and AT+3.0℃, respectively. YGrain yield was decreased by approximately 15% for each temperature elevation of 1.5 ℃. The yield decrease was attributed to the increased sterility and the decreased grain weight under the higher temperature conditio

Brassica napus L. (Brassicaceae) plantation has increased as its seed is the primary source for bio-diesels. This study was conducted Male sterile (MS) line (cv. 'Sun-Mang') to pollen parent (cv. 'Mokpo 64') ratio of rape plants on fatty acid compositions of six sequential stages and yield performances. Ratio of MS line to pollen parent was followed, 4:2, 10:1, and 10:2, respectively. Seeds of six sequential stages (35, 40, 45, 50, 55, and 60 days after flowering) were collected and determined using SEED FAME ESTIMATION. The results showed that oleic acid content (C18:1) of the MS to pollen parent ratio (4:2) relatively increased up to 60 days after flowering compared to other ratios. Other fatty acid compositions such as palmitic acid (C16:0), stearic acid (C18:0), linoleic acid (C18:2) and linolenic acid (C18:3) contents decreased during seed maturation period. Seed weight (1000 seeds) of MS to pollen parent ratio (4:2) was higher than other treatments. These results suggest that fatty acid compositions and seed weight was affected by ratio of MS line to pollen parent. For rape seed production, a suitable ratio of MS line to pollen parent will be required to cultivate rape plantations.

To investigate flowering related genes in winter-type oilseed rape (Brassica napus L. cv. Tammi), differentially expressed genes were isolated from leaves of the plant after low temperature treatment which is requirements for floral induction. As a result of suppression subtractive hybridization (SSH), 288 clones were randomly selected from SSH library. Using reverse Northern blot analysis, 150 of 288 clones were identified to be differentially expressed. Out of these 150 clones, 45 clones showed very high identities with the known genes. Four clones showed very high identities over 90% with metallothionein-like gene that is related to flowering-induced genes. Of these 4 clones, the cDNA clone, rfs-13, revealed high identity with meotallothionein-like protein in Arabidopsis thaliana (98%) and Brassica compestris (89%). Furthermore, gene expressed in immature flower stages was confirmed by Northern blot analysis.

Rapeseed(Brassica napus L.) is an important oil crop as a vegetable oil, concentrated feed and industrial materials. The name "canola" was registered in 1979 by the Western Canadian Oilseed Crushers Association to describe "double-low" varieties. Double low indicates that the processed oil contains less than 2% erucic-acid and the meal less than 3mg/g of glucosinolates. Today annual worldwide production of rapeseed is approximately 35 million tons on 24 million hectares. China accounts for 33% of the world production and the European Economic Community for nearly 32%. Canola ranks 3rd in production among the world's oilseed crops following soybeans, sunflowers, peanuts and cottonseed. The recent advances in genomics and in gene function studies has allowed us to understand the detailed genetic basis of many complex traits, such as flowering time, height, and disease resistance. The manipulation of seed oil content via transgene insertion has been one of the earliest successful applications of modern biotechnology in agriculture. For example, the first transgenic crop with a modified seed composition to be approved for unrestricted commercial cultivation in the US was a lauric oil, rape-seed, grown in 1995. There were also some significant early successes, mostly notably the achievement of 40% to 60% lauric acid content in rapeseed oil, which normally accumulates little or no lauric acid. The name "~textrmLauricalTM " was registered in 1995 by Calgene Inc. Nevertheless, attempts to achieve high levels of other novel fatty acids in seed oils have met with much less success and there have been several reports that the presence of novel fatty acids in transgenic plants can sometimes lead to the induction of catabolic pathways which break down the novel fatty acid, i.e. the plant recognizes the "strange" fatty acid and, far from tolerating it, may even actively eliminate it from the seed oil. It is likely that, in the future, transgenic oil crops and newly domesticated oil crops will both be developed in order to provide the increased amount and diversity of oils which will be required for both edible and industrial use. It is important that we recognize that both approaches have both positive and negative points. It will be a combination of these two strategies that is most likely to supply the increasing demands for plant oils in the 21st century and beyond.ant oils in the 21st century and beyond.

Rapeseed as a partial allogamous crop(allogamy rate : 25~75%) displays depression by continuous selfing. Therefore, it is essential to produce F1 hybrids with high yield using cytoplasmic genetic male sterility(CGMS). This breeding system needs to develop