湿地松体胚增殖与成熟培养研究

以湿地松未成熟合子胚为试验材料,诱导获得胚性胚柄细胞团(Embryogenic Suspensor Mass-ESM),通过培养基的优化,开展湿地松ESM维持与增殖及体胚成熟培养的研究。研究结果表明:基本培养基与植物生长调节剂组合影响ESM的增殖速率及质量,DCR+NAA1.0mg·L-1+6-BA0.32mg·L-1+KT0.30mg·L-1为湿地松ESM的最佳增殖培养基;在无植物生长调节剂培养基上的预培养是湿地松体胚发育、成熟的必要程序,ABA、PEG、AC和高浓度蔗糖的组合进一步促进了体胚的发育成熟,体胚在培养基LP+ABA50mg·L-1+PEG600020%+6%蔗糖+AC2.5g·L-1上获得了近子叶期体胚,但未能获得完全成熟的体胚。

‘宁杞8号’体细胞胚胎发生体系建立

以宁夏枸杞新品种‘宁杞8号’幼嫩叶片为外植体,探讨激素组合及添加物对‘宁杞8号’体细胞胚胎诱导、体胚增殖、萌发和植株再生的影响,并建立高效稳定的体细胞胚胎发生体系。结果表明:通过对6-BA、2,4-D和IAA进行正交分析,筛选出‘宁杞8号’体细胞胚诱导最优激素组合:6-BA 1.0 mg·L^(-1)+2,4-D0.3 mg·L^(-1)+IAA 0.4 mg·L^(-1),体胚诱导率达88.67%。极差分析比较各激素间的影响,6-BA对体胚诱导影响最显著。当高浓度的生长素及低浓度细胞分裂素浓度适宜的配比时,才能诱导产生形态正常数量多的‘宁杞8号’体细胞胚。在体胚增殖培养中,6-BA的浓度过高易导致玻璃化,不利于‘宁杞8号’体胚增殖生长。随着激素浓度的增高,体胚增殖倍数增加,玻璃化率也越高,综合分析得到‘宁杞8号’最佳体胚增殖培养基为6-BA 0.4 mg·L^(-1)+NAA 0.6 mg·L^(-1)。当添加IBA 0.3 mg·L^(-1)+GA_30.4 mg·L^(-1)+蔗糖10 g·L^(-1)时,‘宁杞8号’体胚萌发率最高,萌发率达89.17%。添加GA_3及低浓度蔗糖能促进成熟的体胚萌发。对‘宁杞8号’体萌发的影响程度依次是IBA>蔗糖>GA_3。活性炭能有效提高‘宁杞8号’体胚再生植株率,同时对萌发体胚的根的发育也有促进作用,当IBA 0.1 mg·L^(-1)+KT 0.4 mg·L^(-1)+活性炭1 g·L^(-1)时,‘宁杞8号’体胚再生植株效果最佳,体胚再生率达91.67%。

Ontogeny of rat chondrocyte proliferation:studies in embryo,adult and osteoarthritic (OA) cartilage

The aim of this work was to study the ontogeny of chondrocyte cell division using embryo, adult and osteoarthritic(OA) cartilage. We searched for mitosis phases and performed a comparative evaluation of mitotic index, basic fibro-blast growth factor b (FGFb), transforming growth factor β1 (TGF-β1) receptors, cyclin dependent kinase (CDK1)and Cyclin-B expression in fetal, neonate, 3, 5, 8 weeks old rats and experimental OA. Our results showed that mitosisphases were observed in all normal cartilage studied, although, we found a decrease in mitotic index in relation to tissuedevelopment. No mitosis was detected in OA cartilage. We also found a statistical significant reduction in cell number inOA cartilage, compared with the normal tissue. Furthermore, FGFb and TGF-β1 receptors diminished in relation totissue development, and were very scarce in experimental OA. Western blot assays showed CDK-1 expression in allcases, including human-OA cartilage. Similar results were observed for Cyclin-B, except for 8 weeks, when it was notexpressed. Our results suggest that cell division seems to be scarce, if not absent within the OA cartilage studied.Nevertheless, the existence of factors essential for cell division leaves open the question concerning chondrocyteproliferation in OA cartilage, which is likely to be present in the early stages of the disease.

Effect of Abscisic Acid on NaCI Stressed Callus Proliferation and Plant Regeneration in Rice

In rice, 2,4-Dichlorphenoxyacetic acid （MS2） has been considered best for callus induction and combination ofNAA, IAA, ABA （MS3） for somatic embryogenesis. Efficient plant regeneration was observed when MS basal salts supplied with 3% sorbitol and 3% maltose as carbon sources without hormones （MSac）. During this experiment, effect of sodium chloride （NaCl） and abscisic acid （ABA） was assessed on callus growth, plant regeneration and root induction efficiency of rice （Oryza sativa L.） varieties IR-6 and Basmati-370. Callus proliferation rate was highly decreased in both varieties on MS2b （100 mol.m3 NaCl ＋ 0.5 mg＇L1 ABA） than MS2a （100 mol＇m3 NaCl） cultures significantly. Proline, glycine-betaine and reducing sugars were increased significantly in MS2a and MS2b callusing cultures. However, total proteins were decreased in MS2a, while slightly increased in MS2b. Maximum plant regeneration （9.42 ±0.54 and 10.67 ±0.50 plantlets.callus1） from somatic embryos was observed on MS4c in IR-6 and Basmati-370, while 1.56 ± 0.06 （IR-6） and 0.95 ±0.05 （Basmati-370） plantlets callus1 were observed on MSab （100 mol·m3 NaCl）. No plant regeneration was observed on MS4b （100 mol·m3 NaCl ＋ 0.5 mg·L-1 ABA） medium in both varieties. Inhibition of root induction efficiency was high in MSsb （100 mol·m3 NaCl ＋ 0.5 mg·L-1 ABA） than MS5a （100 mol·m3 NaCl） in the stressed cultures （P 〈 0.05）. In this experiment, it was concluded that ABA involved in somatic embryogenesis and elevation of NaCl stress, while it causes inhibition of cell＇s growth as well as its regeneration into plantlets from somatic embryos.