剪叶对茭白肉质茎膨大的影响

以 1个单季茭和 1个双季茭茭白品种为试材 ,在肉质茎开始膨大时进行不同程度的剪叶处理 ,结果表明 :各处理在开始膨大后最初几天内干、鲜质量差异不明显 ;剪去叶片对肉质茎膨大影响不大 ,但切除叶鞘后 ,肉质茎膨大初期以后的干、鲜质量显著下降 ;整株剪叶比单茎剪叶处理对肉质茎膨大的影响大 ,剪去叶片与切除叶鞘、叶片表现相似。由此认为 ,茭白肉质茎膨大所需养分主要依靠短缩茎和叶鞘在肉质茎膨大前的积累 ,肉质茎膨大过程中植株茎蘖间存在养分交流 ,品种间在膨大速率上有一定差异。     

怎样防除雄茭和灰茭

在茭白田内 ,人们往往会发现一些株形高大 ,在孕茭期不能结茭白的植株 ,通常称为雄茭 ;同时也会发现虽然结茭 ,但肉质茎较小、包叶不开裂的茭白 ,肉质茎剖开后 ,其中充满灰黑色粉末状物 ,这类茭白不堪食用 ,称为灰茭。雄茭、灰茭是如何产生的呢 ?茭白之所以能够形成肥大的肉质茎 ,是因为茭白植株被一种称为菰黑粉菌的真菌寄生后 ,其茎端不正常膨大而成。若茭白植株未被黑粉菌侵染寄生 ,则不能形成茭白的产品器官即可食用的肉质茎 ,有些植株可以抽穗开花。这些茭白植株即为通常称的雄茭。而另一些植株被毒力强的菌种侵染 ,膨大的肉质茎内形成…     

茭白碳水化合物积累与分配特性研究

 以茭白品种‘蒋墅茭’和‘葑红早’为试材的研究表明: 在肉质茎膨大之前, 植株茎蘖各部位的总糖、还原糖、淀粉积累量持续上升, 短缩茎中积累量最高; 肉质茎膨大开始时, 各部位碳水化合物积累量下降, 以短缩茎的下降量最大, 认为膨大前叶片的光合产物在短缩茎和叶片中积累以短缩茎为主,植株积累的碳水化合物主要以淀粉形式存在。孕茭前¹⁴C 同化物在短缩茎的分配率较大, 上位叶片、叶鞘也有较多积累, 肉质茎膨大过程中, 大量的¹⁴C 同化物在肉质茎中积累。饲喂叶片光合产物除供应自身茎蘖外, 还向植株其它各部位输送。     

茭白主茎地上部养分积累和转运规律

以两个有代表性的茭白品种为试材,测定了植株主茎生育过程中地上各部位干、鲜质量的积累及叶片净光合速率的变化。结果表明在田间封行前,植株主茎叶和短缩茎的干、鲜质量持续缓慢增加;封行后至肉质茎快速膨大前,短缩茎的物质积累超过叶片和叶鞘;肉质茎快速膨大期间,干物质积累主要在其前期,同时短缩茎等其余部位干、鲜质量明显下降;之后肉质茎干、鲜质量增加趋缓,叶片、叶鞘质量仍持续下降,而短缩茎质量回升,进入新一轮物质积累期;主茎的总干物质量在封行后迅速提高,在肉质茎充分膨大后下降。功能叶片净光合速率在生育进程中总体呈持续缓慢下降的趋势,肉质茎快速膨大期间迅速大幅上升,紧接着又快速回落。     

茭白遗传多样性与育种技术

茭白产品器官是茭白植株受菰黑粉菌侵染膨大后形成的肉质茎。通过分析茭白遗传多样性和遗传变异,认为茭白遗传变异来源很可能主要来自菰黑粉菌的遗传变异。讨论了茭白育种技术及需要研究的问题。     

茭白膨大前后肉质茎中抗坏血酸含量变化初探

对茭白肉质茎膨大前后的主要内源抗氧化剂—抗坏血酸水平以及膜脂过氧化产物—丙二醛（MDA）含量的变化作了研究。结果表明,肉质茎膨大后,其MDA含量大幅增加,抗坏血酸含量大幅下降,氧化型抗坏血酸比例显著上升。而同时期成熟叶片中的MDA含量基本不变。说明茭白肉质茎在黑粉菌大量繁殖引起膨大的过程中存在较强烈的氧化胁迫。     

茭白肉质茎形成的初步研究

茭白肉质茎可能是由营养茎的顶端生长点膨大而成，并阐述了理由。     

茭白肉质茎膨大过程中的糖代谢与激素含量变化

 以单季茭白品种‘蒋墅茭’和双季茭白品种‘葑红早’为试材, 研究了秋季肉质茎膨大过程中物质运转的相关生理生化变化。结果表明, 随着肉质茎鲜质量、干质量快速增加, 非结构性碳水化合物主要成分含量总体上升, 后期出现下降, 蒋墅茭肉质茎中蔗糖含量较高; 糖分转化关键酶活性总体较高,转化酶活性以酸性转化酶较高且呈快速下降, 蒋墅茭的酸性转化酶活性高于葑红早而中性转化酶活性较低;蔗糖合成酶的分解方向活性显著高于合成方向, 且后期维持较高水平, 葑红早的双向活性均高于蒋墅茭;Z + ZR总体含量最高、下降最明显, GA₄ 其次, IAA也呈缓慢下降趋势, GA₃、ABA含量极低, 且各激素均以葑红早高于蒋墅茭。茭白肉质茎干、鲜质量处于快速增长阶段的同时, 而内部生理生化快速下降, 说明茭白肉质茎膨大过程具有特殊性, 并且品种间存在差异。     

长江流域塑料大棚 茭白栽培技术

正茭白别名茭瓜、茭笋、蒿芭等,是禾本科菰属多年生宿根草本沼泽植物。原产中国,由同种植物菰演变而来。茭白的食用部分为变态的肉质嫩茎,是植株被菰黑粉菌寄生后,茎尖受病菌分泌物吲哚乙酸刺激,畸形膨大而成。茭白为我国特有的一种水生蔬菜,栽培历史2 000 a以上。目前,作为蔬菜栽培的,仅有中国和越南,我国长江流域以南及台湾     

水生蔬菜答农民问(16):什么样的条件适合种植茭白? 茭白栽培形式主要有哪些?

正茭白(Zizania latifolia Turcz.)是禾本科(Gramineae)菰属的一种多年生宿根性挺水草本植物,原产我国,又叫蒿巴、茭笋、蒿笋、茭白笋、蒿巴笋、茭荀、茭瓜等。茭白是中国特有的一种水生蔬菜,食用部分为变态的肉质嫩茎,系植物受菰黑粉菌(Ustilago esculenta P. Hen)寄生后,营养茎组织受病菌分泌物吲哚乙酸剌激膨大而成。据中国预防医学科学院营养与食品卫生研究所资料(1991年),每100 g茭白(膨大肉质茎)食用部分中含水分     

Effect of homocysteine on the expression of macrophage inflammatory protein-1α in THP-1 monocytes

AIM: To investigate whether homocysteine (HCY) induce the expression of macrophage inflammatory protein-1α(MIP-1α)in cultured THP-1 monocytes. METHODS: After exposure of THP-1 monocytes to HCY at increasing concentrations (0.05,0.1 and 0.2 mmol/L) for 8 h, or at 0.1 mmol/L of HCY for different incubation times (4, 8 and 16 h), the expressions of MIP-1α mRNA and protein were determined by RT-PCR and immunocytochemistry, respectively. RESULTS: RT-PCR showed that the expression of MIP-1α mRNA increased with the concentrations of HCY compared with the control group. Meanwhile, after the treatment of 0.1 mmol/L HCY to the cells for different times, the MIP-1α mRNA expression increased at 4 h, peaked at 8 h, and then decreased at 16 h. The authenticity of RT-PCR products was confirmed by DNA sequencing. Image analysis of Immunocytochemistry assay showed the expression of MIP-1α protein in experimental groups increased in a dose- and time-dependent manner(P＜0.01). CONCLUSIONS: HCY induced monocytes to express MIP-1α mRNA and protein.     

Effects of advanced glycation end products on protein and mRNA expression of macrophage inflammatory protein-1α in cultured human umbilical vein endothelial cells

AIM: To investigate the effects of advanced glycation end products (AGEs) on protein and mRNA expression of macrophage inflammatory protein-1α (MIP-1α) in cultured human umbilical vein endothelial cells(HUVECs). METHODS: HUVECs were cultured with AGEs at different concentrations for 24 h and at a concentration of 400 mg/L for different time.The levels of mRNA and protein expression of MIP-1α in cultured HUVEC were detected by in situ hybridization and Western blot, respectively. RESULTS: In situ hybridization showed that after exposure of HUVECs to AGEs at different concentrations (100 mg/L, 200 mg/L, 400 mg/L) for 24 h, the average integrated optical density values (18.76±3.17, 26.58±1.61, 34.23±2.25) of MIP-1α mRNA expression in HUVECs were higher than that in control group (13.83±1.24, P0.05). After exposure of HUVECs to AGEs at a concentration of 400 mg/L for 12 h, 24 h and 36 h, the average integrated optical density values of MIP-1α mRNA expression in HUVECs were 22.67±1.46, 34.23±2.25 and 42.28±3.14, higher than that in 0 h group (12.56±1.24, P0.05). Western Blot showed that exposure of HUVECs to AGEs at different concentrations(100 mg/L, 200 mg/L, 400 mg/L) for 24 h resulted in a 1.34-fold, 1.87-fold and 2.46-fold increase in the expression of MIP-1α protein in HUVECs compared with BSA control group (P<0.05). Meanwhile, exposure of HUVECs to AGEs at a concentration of 400 mg/L for 12 h, 24 h and 36 h resulted in a 1.82-fold, 2.71-fold and 3.34-fold increase in MIP-1α protein expression in HUVECs compared with 0 h group (P<0.05). CONCLUSION:These data suggest that AGEs could induce a high expression of MIP-1αmRNA and protein in cultured HUVECs in a dose-dependent and time-dependent manner.     

Antagonistic effect of captopril on activation and injury of vascular endothelial cells induced by lipopolysaccharide

AIM: To investigate the antagonistic action of Captopril (Cap) on the activation and injury of human umbilical vascular endothelial cells (HUVECs) induced by lipopolysaccharide(LPS) and the possible mechanisms. METHODS: After 18 h exposure of the cultured HUVECs to LPS (1 mg/L), or LPS (1 mg/L) plus Cap at the concentration of 10^-7mol/L, 10^-5mol/L and 10^-3mol/L, the expression of vWF protein in the conditioned media was tested by enzyme-linked immunosorbent assay (ELISA), the expression of ICAM-1 protein in HUVECs was determined by indirect immunofluorescence technique with flow cytometry as well. In addition, the expression of TNFα mRNA was determined by in situ hybridization. RESULTS: The results of ELISA and indirect immunofluorescence technique showed that exposure to LPS at a concentration of 1 mg/L led to a significant increase in the vWF and ICAM-1 expression in HUVECs as compared to the control (P＜0. 05), whereas they were somewhat decreased when exposed to Cap at three increasing concentrations mentioned above, especially in the Cap (10^-3mol/L) plus LPS group (P＜0.05). Cap inhibited vWF secretion and ICAM-1 expression of HUVECs caused by LPS in a concentration-dependent manner. In situ hybridization revealed that the expression of TNFα mRNA was inhibited by Cap both in a concentration of 10^-3mol/L, and in a lower concentration of 10^-5mol/L. CONCLUSION: Cap antagonizes the activation and injury of HUVECs induced by LPS, which may be related to the decrease in TNFα mRNA expression.     

Expression of MIP-1α and RANTES gene and protein in the bronchus of murine asthma

AIM: To study the role of the gene and protein expression of MIP-1α and RANTES in the bronchus of murine asthma. METHODS: 20 male BALB/C mice were randomly divided into two groups: the control group (A₀ group) and asthma group (B₀ group). In the experiment, the mice model of asthma was established by the ovalbumin (OVA) challenge methods. The protein expression of MIP-1α and RANTES were detected by immunohistochemistry methods. The gene expressions of MIP-1α and RANTES were detected by in situ hybridization methods. RESULTS: Immunohistochemistry showed that the expressions of MIP-1α protein and RANTES protein around the bronchus of group B₀ were significantly higher than those of group A₀ (P<0.01), the epithelial cells were the chief expression cells; (2) In situ hybridization showed that the expressions of MIP-1α gene and RANTES gene around the bronchus of group B₀ were significantly higher compared to those of group A₀ (P<0.01), the epithelial cells were the chief expression cells. CONCLUSION: MIP-1α and RANTES are high expression in the bronchus epithelial cells in experimental murine asthma.     

Effects of eicosapentaenoic acid on expression of nuclear factor κB and release of cytokines in human umbilical vein endothelial cells stimulated by lipopolysaccharide

AIM: To investigate the effects of eicosapentaenoic acid(EPA) on the expression of nuclear factor kappa B(NF-κB) and release of vascular endothelial growth factor(VEGF), IL-1α and IL-6 in cultured human umbilical vein endothelial cells(HUVECs) stimulated by lipopolysaccharide(LPS).METHODS: HUVECs were obtained from cell strain and cultured in vitro. HUVECs were divided into 4 groups: control group, LPS group, 0.030 g/L EPA treatment group and 0.050 g/L EPA treatment group. The cells were cultured with LPS alone in LPS group and incubated with EPA for 1 h in the EPA pretreatment groups at the concentrations of 0.030 g/L and 0.050 g/L before LPS stimulation. Twenty-four hours after stimulated by LPS, the protein expression of NF-κB p65 in HUVECs were assessed by Western blotting analysis at different time points. The production of VEGF, IL-1α and IL-6 in cultured HUVECs was evaluated by ELISA. The effects of EPA on the protein expression of NF-κB p65 and the production of VEGF, IL-1α and IL-6 in HUVECs challenged by LPS were also determined.RESULTS: Compared with control group, the protein expression of NF-κB p65 was significantly increased in HUVECs induced by LPS and was inhibited by EPA. Compared with control group, the protein expression of VEGF, IL-1α and IL-6 was dramatically increased in HUVECs induced by LPS and most of the increase was inhibited by EPA.CONCLUSION: LPS enhances the protein expression of NF-κB and the release of VEGF, IL-1α and IL-6. EPA inhibits the protein expression of NF-κB, and the production of VEGF and the inflammatory cytokines in cultured HUVECs stimulated by LPS, indicating that EPA may be useful for preventing and treating neovascular and inflammatory diseases.     

Native and oxidized low density and very low density lipoprotein enhance the expression of MIP-1α mRNA in aortic smooth muscle cells

AIM: To understand whether native and oxidized low density and very low density lipoprotein (n-LDL, n-VLDL, ox-LDL, ox-VLDL) enhance the expression of macrophage inflammatory protein (MIP)1α mRNA in cultured aortic smooth muscle cells (SMCs). METHODS: Native low density and very low density lipoprotein were isolated from normal blood donors by density gradient ultracentrifugation, and were oxidatively modified by adding CuCl2. After a 24 h-exposure of the cultured SMCs to n-LDL， n-VLDL， ox-LDL and ox-VLDL, respectively, the expression of MIP-1α mRNA was determined by in situ hybridization and RT-PCR. RESULTS: Cultured aortic SMCs expressed MIP-1α mRNA at low level. N-LDL， n-VLDL， ox-LDL and ox-VLDL enhanced the expression of MIP-1α mRNA in SMCs, ox-LDL and ox-VLDL showed stronger effect than n-LDL and n-VLDL, respectively. The effect of ox-VLDL was most striking. There was a significant difference between groups (P<0.01). CONCLUSION: N-LDL, n-VLDL, especially ox-LDL and ox-VLDL, may play an important role in the formation of early atherosclerotic lesion by inducing SMCs to express MIP-1α.     

Effects of uremic serum on the proliferation and trans-differentiation of human renal tubular epithelial cells

AIM: To explore the effects of uremic serum on proliferation and trans-differentiation of human renal tubular epithelial cells. METHODS: Human renal tubular epithelial cell line (HK-2) was cultured in RPMI-1640 medium. The proliferation effects of uremic serum at different concentrations were evaluated by methylene blue assay (MTT method) and flow cytometry. The positive cells percentage of α-smooth muscle actin(α-SMA)in different concentration uremic serum medium was also measured by flow cytometry in vitro. RESULTS: Absorbance 490 (A₄₉₀) was increased in 5%-20% uremic serum groups compared with that in normal controls with the use of MTT. Cells in G₁ phase were decreased, but proliferation index (PI) was increased in 10%-20% uremic serum groups compared with that in normal controls with the use of flow cytometry. No significant difference of cell proliferation index was found among uremic serum groups. The positive percentage of α-SMA cells was increased significantly in uremic serum groups compared with that in normal controls, and increased in parallel with the increasing of uremic serum concentration. CONCLUSION:These data suggest that AGEs could induce a high expression of MIP-1αm RNA and protein in cultured HUVECs in a dose-dependent and time-dependent manner.     

Effect of lipid peroxidation on expression of vascular cell adhesion molecule-1 in cultured human endothelial cells

AIM:To observe the expression of vascular cell adhesion molecule-1 (VCAM-1) in cultured human umbilical vein endothelial cells (HUVEC) by lipid peroxidation injury induced by exposure to diamide.METHODS:Expression of VCAM-1 mRNA and protein in HUVEC was determined by in situ hybridization and a cell enzyme-linked immunosorbent essay (cell ELISA), respectively.RESULTS:The HPIAS-1000 image analytic system in situ hybridization detected that the mean absorbance values in experiment groups(1, 5 and 10 μmol/L diamide for 8 hours) were 0.147±0.013, 0.292±0.020 and 0.396±0.022, which were 1.91-fold, 3.79-fold and 5.14-fold as much as that of the control group (0.077±0.011), respectively. There was significant statistical difference between groups (P＜0.01). The cell ELISA showed that the mean absorbance values of VCAM-1 proteins in experiment groups were 0.158±0.008, 0.220±0.017 and 0.321±0.023, which were 1.53-fold, 2.12-fold and 3.09-fold as much as that of the control group (0.104±0.016), respectively. The analysis of variance proved the significant difference between groups (P<0.01).CONCLUSION:The results suggest that the increased expression of VCAM-1 is integral in promoting adhesion of monocytes to the vascular endothelium.