基因型和供水对小麦维管系统发育的效应

在不同灌水条件下对不同冬小麦基因型的旗叶至倒四叶、主茎基部第 2节间及穗下节间维管束结构进行了观察分析。结果发现 ,叶片维管束数目随叶位下降而依次递减 ,存在明显基因型差异且集中表现于顶部三叶片。冬前水对小麦叶片维管束数目发育有明显促进 ,春季返青后供水对其促进作用很小 ,但对叶片大小促进作用明显。水分和养分输导组织在茎秆结构中体现出基因型差异。完全控水条件下水分及养分输导组织发育均受到抑制 ,不同供水对叶片形态及维管束结构的发育均有明显效应 ,供水对前者效应大于后者。拔节水对茎秆维管系统发育起决定性作用     

血管内皮生长因子及其受体在胚胎卵黄囊 不同发育时期的表达

为研究胚胎不同时期VEGF、KDR和CD34在人卵黄囊中的表达情况，了解胚胎造血的发育过程和机理。采用免疫组织化学SP法卵黄囊冰冻切片进行染色，光镜观察。结果发现在第3~4周的人卵黄囊低表达VEGF和KDR，不表达CD34。4~6周组强表达VEGF、KDR和CD34。在血岛内阳性细胞大而圆，成簇或分散聚集，有些细胞沿血岛边缘形成血管样结构。6周以后，卵黄囊弱表达VEGF、KDR和CD34。上述结果提示卵黄囊可表达造血和血管生成相关因子，随胚胎发育呈阶段性表达。卵黄囊中出现造血干细胞和血管内皮细胞的分化。     

野败型不育系稻穗闭颖慢原因的探讨

 野败型不育系稻穗开颖迟、闭颖慢的原因与其浆片中维管束数目少、导管和维管束薄壁细胞不发达有关。闭颖过程受小穗轴控制，并受温度影响，而与受精过程无关。水稻颖花能在水中开闭。     

小麦品种抗赤霉病穗轴病理解剖的研究

研究了不同抗赤霉病类型品种的病理解剖学；发现抗病品种穗轴线管束数量比感病品种的多；穗轴节上部的节间组织排列较下部节间组织致密；菌丝体只存在于穗轴维管束的导管内．并且抗病品种内的菌丝体数量比感病品种数量少、且发育不良；感病品种穗轴组织的坏死速率为抗病品种的７倍。     

Inhibition of Ang-2 and RGS-5 expression by nanogold results in normalization of vascellum in hepatic tumor

AIM: To observe the vascular normalization effect of nanogold on hepatic tumor by inhibiting angiopoietin-2 (Ang-2), regulator of G-protein signaling-5 (RGS-5) during certain time window. METHODS: H22 cells, the hepatocellular cancer cell line, were subcutaneously injected into the right armpits of 48 BALB/c nude mice. When the size of transplanted tumor reached 3~4 mm, the mice were divided into 2 groups: 36 mice in experiment group and 12 mice in control group. The mice in experimental group underwent injection of nanogold into the tumor once a day, and the mice in control group were injected with normal saline. After continuous treatment with nanogold for 3 days, 7 days and 11 days, the mice were sacrificed, the liver tumors were taken out to measure the size and weight. The expression of Ang-1,Ang-2 and RGS-5 in the tumor was detected by the method of immunohistochemical staining. The normalizing shapes of tumor vessels and the pericytes were observed under electronic microscope. RESULTS: With nanogold treatment for 3 days, 7 days and 11 days, the positive rates of Ang-1 were 16.7％, 50.0% and 16.7%, respectively. The positive rates of Ang-2 were 33.3%, 16.7% and 41.7%, respectively. The expression of Ang-1 in experiment group was higher than that in control group, especially at the 7th day in experiment group. The expression of Ang-2 in experiment group was lower than that in control group (58.3%), especially at the 7th day in experiment group. With nanogold treatment for 3 days, 7 days and 11 days, the positive rates of RGS-5 were 33.3%, 16.7% and 50.0%, respectively. The immature pericyte coverage indexes (IMPI) were 19.6%±4.3%, 32.5%±7.9% and 41.2%±9.1% respectively. At the 7th day in experiment group, the positive rates of RGS-5 and IMPI were lower than those in other experiment groups and control group. After treated with nanogold for 7 days, the pericytes in the parietal wall of the blood vessels in the tumor showed the tendency to grow normally in morphology and were completely covered by endothelial cells. However, the pericytes in the parietal wall of the blood vessels in control group showed differences in size, impaired integrity and only a few of the pericytes covered by endothelial cells. CONCLUSION: During the time window of nangold treatment for 7 days, the chemical can normalize the blood vessels in liver cancer by inhibiting the expression of Ang-2 and RGS-5.     

Proliferative effect of PDGF and anti-proliferative activity of AMPK on vascular smooth muscle cells

AIM: To investigate the proliferative effect of platelet-derived growth factor (PDGF) and anti-proliferative activity of AMP-activated protein kinase (AMPK) on vascular smooth muscle cells (VSMCs). METHODS: The proliferation of VSMCs cultured with PDGF and activation of AMPK were observed. VSMCs were divided in 4 groups: control group; PDGF group; 5-aminoimidazole-4 -carboxamide-1-β-D-riboside (AICAR) group and AICAR+PDGF group. The time course of AMPK activation was determined. The protein level of mTOR was also measured. RESULTS: Compared with control group, the proliferative rate in PDGF group was significantly increased. The growth of VSMCs was inhibited in a time-dependent manner and the activity of p-mTOR was significantly decreased in AICAR group. Compared with control group, the expression of p-AMPK in PDGF group was significantly decreased, and that in AICAR group and AICAR+PDGF group was significantly increased. The expression of p-AMPK in AICAR+PDGF group was higher than that in PDGF group. The activity of p-mTOR in PDGF group was significantly higher than that in control group, while that of AICAR group and AICAR+PDGF group was significantly decreased. The expression of p-mTOR in AICAR+PDGF group was lower than that in PDGF group. CONCLUSION: Stimulation of VSMCs with PDGF promotes the cell proliferation, which can be inhibited by AICAR. The proliferation of VSMCs activated by AMPK is probably correlated with the down-regulation of mTOR expression.     

Construction of a lentiviral RNA interference vector targeting rat myocardin and its effect on vascular smooth muscle cell differentiation

AIM: To construct a lentiviral RNA interference(RNAi)vector targeting rat myocardin mRNA and to investigate its effect on the differentiation of vascular smooth muscle cells(VSMCs).METHODS: Three pairs of dsDNA targeting rat myocardin mRNA were designed, synthesized and cloned into lentiviral vector pGCSIL-GFP to generate pGCSIL-GFP-shMyocd lentvirus. A Flag-tagged myocardin-overexpression vector pEGFP-N1-Myocd was constructed with pEGFP-N1/X124G. After these two vectors were cotransfected into 293T cells, the flag protein was assessed by Western blotting to analyze the knockdown effect of pGCSIL-GFP-shMyocd. The expression of myocardin and SM22α was also detected by RT-PCR and Western blotting after the pGCSIL-GFP-shMyocd viruses were transfected into primary cultured rat aortal VSMCs.RESULTS: The rat myocardin lentviral RNAi vector pGCSIL-GFP-shMyocd and myocardin-overexpression vector pEGFP-N1-Myocd were successfully constructed. After these two kinds of vectors were cotransfected into 293T cells,the No.1 interfering vector displayed the highest inhibitory effect on flag expression.After the No.1 lentvirus at the titer of 1×10¹² TU/L was transfected into VSMCs, the myocardin and SM22α expression was significantly attenuated. CONCLUSION: The lentiviral pGCSIL-GFP-shMyocd RNAi vector is successfully constructed, which is useful for further study regarding the molecular mechanism of the phenotypic switching in VSMCs under special pathological conditions such as atherosclerosis. Inhibition of myocardin expression in VSMCs leads to the decrease in the expression of differentiation marker, and implies a crucial role of myocardin in VSMCs differentiation.     

Recent progress in conservation of threatened Spanish vascular flora: a critical review

The transfer of legal responsibilities from the Central Government to the Autonomous Communities ended a tradition of paying little attention to endangered Spanish flora. The studies undertaken to implement the European Natura 2000 network, and to prepare regional ‘Red Data Books’ and lists of protected flora offered a much better view of which species were really at risk. As a consequence, a growing number of botanists is now involved in different aspects of conservation biology. The recent publication of a new Spanish Red List of vascular flora has provided the groundwork for the so-called ‘Threatened Flora Atlas’ project, which will update and homogenise the information on 500 taxa at risk. This project will produce a new Spanish Red Book and monitor the status of 40 selected species. The Spanish strategy for plant conservation is discussed, pointing out some deficiencies, such as the neglect of non-vascular taxa, the uneven and sometimes uncoordinated local policies and the uncertain future of some current initiatives.     

冬小麦穗—茎维管联络结构及其形成过程对幼穗生长发育的影响

本文系统研究了冬小麦穗－茎维管系统的联络特点及其形成过程，分析了其在小麦幼穗发育中所起的作用。结果表明，小麦穗部维管束主要在旗叶节与茎内维管系统联络，其次是倒二节。其联系是逐步完善的。在幼穗的护颖分化－小花分花以前，穗、茎之间缺少维管联络；到雌雄蕊分化期，穗、茎维管系统依靠原形成层束达到初步联络；药隔形成期时，这种联络已比较完善，达到筛管联结；直到四分体形成期时，穗－茎维管系统的联络才发育完善，同     

植物激素对蚕豆离体茎段自体嫁接的影响

植物激素的浓度与配比影响着蚕豆离体嫁接系统中砧木与接穗间维管束桥的形成。植物激素浓度低时，没有维管束桥的分化，且易褐变坏死；浓度适宜（ＩＡＡ：ｌｍｇ／Ｌ，ＫＴ：０２ｍｇ／Ｌ）时，砧木与接穗间的维管束可直接连通；浓度继续增高时，只有３０％的嫁接组合有维管束桥的分化，呈分支状分布于茎的棱角处，而其余７０％的嫁接组合砧穗间没有维管束桥的分化，从而使嫁接亲和力下降。