共查询到20条相似文献，搜索用时 31 毫秒
1.
R. Goren E.E. Goldschmidt S.P. Monselise 《The Journal of Horticultural Science and Biotechnology》2013,88(4):443-451
Seasonal changes in native auxins, gibberellins and inhibitors in leaves and bark of Shamouti orange trees were studied. In December and February some auxin activity was found in the pH 6.0 ether fraction of leaves. Gibberellins were found mostly in the pH 7.0 water residue, with a peak in December. Large amounts of abscisic acid-like inhibitors were found in the pH 6.0 ether fraction of leaves, and the pH 7.0 water residue contained other inhibitors. Auxin activity in the bark was higher than in leaves, and the amount of inhibiting substances detected in the bark was much lower. Auxins were found in both fractions, whereas gibberellins were found in the pH 7.0 water residue as well as in the pH 3.0 ether fraction.Ringing the trunks of trees in March promoted the accumulation of growth regulators in the bark near the ring and in the leaves. The main effect of ringing in August was an accumulation of acidic gibberellins above the ring during the first three weeks after ringing. 相似文献
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Joanna Nowak Marian Saniewski R. M. Rudnicki 《The Journal of Horticultural Science and Biotechnology》2013,88(4):383-390
Changes in the content of carbohydrates and in the activity of hydrolytic enzymes were studied in hyacinth bulbs exposed to low temperatures. It was found that the amount of insoluble carbohydrate initially present in the scales and buds of hyacinth bulbs decreased greatly after a prolonged period of low temperature treatment. This decrease was greater in rooted bulbs, held at a low temperature for 63 days in natural conditions, than in unrooted bulbs stored in a refrigerator for the same period. At the same time the levels of soluble mono- and oligosaccharides, and of soluble starch, increased in the scales and buds of chilled bulbs. These changes in sugar level were found to be correlated with changes in the activity of certain hydrolytic enzymes. The activity of these enzymes was higher in rooted bulbs than in those which had not rooted before treatment. The activity of hydrolytic enzymes was found to be considerably higher in the flower buds than in the scales. 相似文献
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有机化梨园不同栽培措施节肢动物多样性比较 总被引：5，自引：0，他引：5
运用生物多样性指标对北京顺义地区有机化梨园3个不同栽培区节肢动物群落多样性及其动态进行了系统研究。结果表明,在同一园区内,不同栽培区节肢动物群落的丰富度和均匀度在整个生长季中的动态变化较一致,而优势度出现了明显的时序差别。群落个体数稀植区在大部分时间内均高于其它2区。3个区的主要优势害虫及其天敌在发生时间和数量上有一定差异,早春密植区木虱发生数量较大,稀植区中砂潜、金龟子类害虫以及步甲、蜘蛛类天敌数量相对丰富,入秋后稀植区木虱发生量最大,密植区最小。据此,对主要害虫综合防治体系建立提出了讨论意见。 相似文献
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番茄不同部位中糖含量和相关酶活性的研究 总被引：25，自引：2，他引：25
试验将番茄光合产物运转途径上叶片(源) 、运输系统以及果实(库) 区分开, 分别测定其糖的组成和含量以及糖代谢相关酶的活性。结果表明: 番茄光合产物运转途径上从“源”到“库”各部位糖的组成和含量不同。叶肉中果糖的含量最高, 蔗糖的含量最低; 中筋中以果糖和葡萄糖为主; 叶柄维管束中葡萄糖含量最高, 蔗糖含量次之, 果糖含量最低。节间和果柄维管束中主要含有蔗糖。果实维管束以及果实内各部位中则主要含有葡萄糖和果糖, 且两者含量无显著差异, 蔗糖含量很低。萼片中葡萄糖含量最高, 蔗糖含量最低; 果蒂中3种糖含量均较高且无显著差异。番茄叶肉及光合产物运转组织中转化酶活性很低, 而在库器官的非维管组织中转化酶活性较高。果蒂中的蔗糖合成酶( SS) 活性最高, 其次是叶肉和运转组织, 果实内各部位中SS活性较低。在合成蔗糖的器官—叶肉中, 有较高的蔗糖磷酸合成酶( SPS) 活性, 运转组织中的SPS活性较叶肉中降低, 但果柄维管束和果实维管束中则表现出较高SPS活性, 果肉、果胶质胎座及心室隔壁中的SPS活性最低。 相似文献
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The deposition of calcium in tomato fruit grown at a range of salinities (electrical conductivities between 3 and 17 mS cm“1), with or without IAA-transport inhibitor treatment, was investigated. Calcium (Ca) in the flesh and pulp of tomato fruit was sequentially separated into four fractions: FI soluble in water, FII soluble in 2.5 mol dm“3 NaCl, Fill soluble in 2% acetic acid and FIV soluble in 5% HC1. In mature fruit, grown at 3 mS cm“1, more than half the Ca was in FI, and the Ca concentration was higher in the pulp than in the flesh. FII and Fill each contained less than 20% of the Ca, and the Ca concentration was higher in the flesh than in the pulp. In general, salinity reduced the concentration of Ca in all fractions and slightly altered the proportional distribution of Ca in fractions. The deposition of calcium in young fruit, grown at 3 and 8 mS cm“1, was highest in FII in the flesh or in FI in the pulp. When 45Ca was supplied to detached fruit, the patterns of45 Ca distribution in the fractions were similar to that of total Ca. Treatment with an IAA-transport inhibitor, CME, reduced both the uptake and transport of 45Ca. While the amount of 45Ca in all fractions was significantly reduced by CME, the proportional distribution of 45Ca among fractions was not affected substantially. Although the proportional deposition of Ca in different fractions was not significantly affected by either salinity or CME, further reduction of the intrinsically low deposition of Ca in FII of distal pulp caused by these factors may be the cause of blossom-end rot in tomato fruit. 相似文献
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AIM: To evaluate the changes of somatotropin axis in pre-pubertal rats with catch-up growth born small for gestational age (CUG-SGA). METHODS: The SGA rat model was prepared by diet restriction in pregnant rats.Growth hormone (GH) excretion in 24-h urine, serum level of insulin-like growth factor-1 (IGF-1), the expression of IGF-l and insulin-like growth factor-1 receptor (IGF-1R) in the tibial growth plate and the mRNA expression of IGF-1 in liver were measured in infant rats at the end of week 4. RESULTS: The level of 24-h urinary GH excretion in CUG-SGA group were significantly higher than that in the rats of non-catch-up growth born small for gestational age (NCUG-SGA) group and appropriate for gestational age (AGA) group (both P<0.01). The serum level of IGF-1 and the mRNA expression of IGF-1 in liver in CUG-SGA group were similar to those in AGA group, but significantly higher than those in NCUG-SGA group. The thickness of the tibial growth plate in NCUG-SGA group was significantly lower than that in CUG-SGA group and AGA group. No difference of the growth plate thickness between CUG-SGA group and AGA group was observed, but the thickness of hypertrophy zone of the growth plate in CUG-SGA group were significantly higher than that in NCUG-SGA group and AGA group (both P<0.01). The expression of IGF-1 in the growth plate in CUG-SGA group was similar to that in AGA group but significantly higher than that in NCUG-SGA group (P<0.01). No difference of the IGF-1R expression in the growth plate among these 3 groups was found (P>0.05). CONCLUSION: GH/IGF-1 resistance exists in SGA rats with and without catch-up growth. 相似文献
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AIM:To investigate Nrf2 that regulates the expression of γ-glutamylcysteine synthetase (γ-GCS) in the inflammatory cells in bronchial asthma guinea pig bronchoalveolar lavage fluid (BALF). METHODS:Adult male guinea pigs were randomly divided into control group (group A), asthmatic group (group B) and dexamethasone group (group C). Asthmatic model was established by the method of ovalbumin challenge. MDA concentration in the lung tissue homogenate was detected. The total cell count and the proportion of inflammatory cells in BALF were measured. The methods of immunohistochemistry and in situ hybridization were used for detection of the protein and mRNA expressions of Nrf2, Bach1 and γ-GCS. RESULTS:(1) The proportion of eosinophils (EOS) in BALF and the MDA concentration of the lung tissue in group B were higher than those in group A and group C. (2) The result of in situ hybridization indicated that the A value of γ-GCS was the highest in group A compared to group B and group C, but the A value of Nrf2 and Bach1 in 3 groups has no statistical significance. (3) Immunohistochemistry indicated that the A value of γ-GCS in group B was lower than that in group A. The positive rate in cell nucleus of Nrf2 in group B was lower than that in group A and group C. The positive rate in cell nucleus of Bach1 in group B was higher than that in group A and group C. (4) The mRNA expression of γ-GCS (A value) showed positive correlation with the positive rate in cell nucleus of Nrf2 and negative correlation with the positive rate in cell nucleus. A negative correlation between the proportion of EOS in BALF of group B and the γ-GCS mRNA was observed. CONCLUSION:There is disequilibrium between oxidation and anti-oxidation in bronchial asthma guinea pig. Inflammatory reaction decreases the expression of γ-GCS in the inflammatory cells in bronchial asthma guinea pig. Dexamethasone regulates the nuclear translocation of Nrf2/Bach1 and increases the expression of γ-GCS. 相似文献
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JIA Jian-tao ZHANG Hui-ying TIAN Xiao-xia JI Jing-quan ZHANG Li-li LV Min-li WANG Li-min FENG Ming ZHAO Zhong-fu HAN De-wu CHENG Ji 《园艺学报》2011,27(8):1580-1585
AIM: To explore the role of 78 kD glucose-regulated protein (GRP78) in the development of hepatopulmonary syndrome (HPS) in rats and the relation to intestinal endotoxemia (IETM). METHODS: The experimental animals were randomly divided into HPS groups of the 4th week, the 6th week and the 8th week. Normal control groups at the corresponding time points were also set up. The Wistar rat model of HPS produced in the process of liver cirrhosis was induced by employing multiple pathogenic factors to the animals. The rats in normal control group were designed by feeding with standard diet and tap water. Histopathological changes of the lung and liver were observed under microscope with the staining of hematoxylin and eosin (HE). The concentrations of alanine amino transferase (ALT), endotoxin and tumor necrosis factor α (TNF-α) in plasma, the contents of TNF-α and malondialdehyde (MDA) in the lung tissues were detected. The expression of GRP78 at mRNA and protein levels in the lungs was measured by the methods of RT-PCR and Western blotting, respectively. RESULTS: The level of endotoxin in plasma was gradually increased with the HPS development. The expression of GRP78 at mRNA and protein levels was also gradually increased with the HPS development and was significant at every time point. The endotoxin in plasma was positively correlated with the expression of GRP78 protein in the lung tissues of the rats with HPS. With the HPS development, the levels of ALT and TNF-α in plasma and the contents of TNF-α and MDA in the lung tissues were gradually increased. The content of endotoxin in plasma and the protein expression of GRP78 in the lung tissues were positively correlated with the contents of TNF-α in plasma and TNF-α and MDA in the lung tissues. The contents of TNF-α in plasma and GRP78 at mRNA and protein levels and TNF-α in the lung tissues were higher in the rats with HPS at every time point than those in normal control group. At the 6th week and the 8th week, the contents of endotoxin and ALT in plasma and MDA in the lung tissues of the rats with HPS were significantly higher than those in normal control group. CONCLUSION: IETM originated from the liver cirrhosis acts as a critical stressor of endoplasmic reticulum (ER) stress and activates ER stress in the lung by oxidative stress, resulting in increased expression of GRP78. Therefore,the increased expression of GRP78 induced by ER stress may play an important role in the development of HPS in rats. 相似文献
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CaM在梨花芽分化过程中的含量变化 总被引：8，自引：0，他引：8
以梨为试材，对成花过程中的短枝芽和叶所含钙调素（ＣａＭ）的含量进行了测定。（１）短枝芽的ＣａＭ含量在整个成花前后都明显高于新梢芽的含量，特别是在成花的发端期突然成倍增加，形成高峰；（２）短果枝叶的ＣａＭ与新梢叶有着相近的变化趋势，但在成花前后，短果枝叶的ＣａＭ含量明显高于新梢叶；（３）ＣａＡｃ处理可以使短枝芽所含ＣａＭ的峰值提前出现，ＴＦＰ处理可明显降低ＣａＭ含量和延迟其峰值到来。还就ＣａＭ在成花过程中的作用及与Ｃａ２＋的关系等问题进行了讨论。 相似文献
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AIM: To study the effect of Ginkgo biloba extract (GbE) on the expression of connective tissue growth factor (CTGF) in the initiating stage of pulmonary fibrosis of rats after administration of bleomycin (BLM).METHODS: The expression of CTGF in lungs was detected by Western blotting. The content of hydroxyproline was assayed by the method of chloramines T. The content of malondialdehyde (MDA) in plasma was investigated by colorimetry.RESULTS: On day 14 after administration of BLM, the contents of CTGF in lungs and MDA in plasma in BLM+NS group were higher than those in NS group, respectively (P<0.05; P<0.01). On day 30 after BLM, the contents of hydroxyproline in lungs and MDA in plasma in BLM+NS group were higher than those in NS group, respectively (both P<0.01). Treatment with GbE ameliorated the above changes induced by BLM. CONCLUSION: GbE ameliorates the up-regulation of CTGF in the initial stage of fibrosis in lungs of rats after administration of BLM. GbE prevents the hyperoxidative injury in lungs of rats after BLM, which might be one of mechanisms underling the effect of GbE on CTGF. 相似文献
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It has been widely appreciated that animal cells rely on the mechanism of regulatory volume decrease(RVD) after swell in a hypotonic environment. Activation of K channels is crucial in the process of self-protection. There are a characterized increase in cytoplasmic Ca and a decrease in pH in the process of RVD in many cell types. Ca entry via transient receptor potential(TRP) channel is crucial for the cytoplasmic Ca increase, which in turn induces the decrease in pH.The increase in cytoplasmic Ca and decrease in pH activate or inhibit the activity of K channel, respectively. In this review, the regulatory network at cellular level between cytoplasmic Ca and pH, and the modulation of K channels by Ca and pH in the process of RVD are discussed. 相似文献
14.
Michael G. Mullins 《The Journal of Horticultural Science and Biotechnology》2013,88(3):237-247
A distinctive seasonal pattern in the outgrowth of shoots was observed in upright maiden apple trees. Until midsummer, extension shoot growth was confined to the apical region of the trunk. After midsummer, vigorous shoots grew from the basal region of the trunk, and the production of these shoots coincided with a decline in growth rates of shoots in the apical region. A similar pattern of shoot growth was evident in trees grown in horizontal and inverted positions but was modified by the effects of gravity, viz. growth curvatures, effects on the symmetry of shoot production about the axis, and changes in the vigour of shoots in the apical and basal regions of the trunk. Growing trees in horizontal and inverted positions caused a reduction in terminal extension growth, but did not reduce the total amount of shoot growth compared with vertically-grown trees. Changing the orientation of the trunk caused differences in the pattern of axillary flower bud formation, but had no detectable effect on the total numbers of flower buds initiated. 相似文献
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生长季苹果硼素营养变化动态及诊断 总被引：4，自引：0，他引：4
田间条件下，玫瑰红／平邑甜茶新生器官全硼变化动态表现不同：短梢叶全硼含量较稳定；长梢叶及其皮部变化动态相似，生长季早期全硼下降，中期升高，后期又下降；果实全硼变化最大，随果实膨大，全硼持续降低，其中以花后一个月降低幅度最大。缺硼植株的果实及长梢皮部全硼显著降低，其它部位全硼含量与缺硼症表现程度之间不一致。果实采收后，长梢皮部全硼含量与次年幼果的全硼含量呈显著正相关。秋季干旱处理长梢皮部全硼含量下降幅度大于叶片和果实。长梢皮部可作为苹果硼素营养的诊断器官。 相似文献
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The effects of combinations of salinity and water table on the mineral content of plum and peach were studied in lysimeters.Chloride content (Cl) in the leaves and the roots of plum and in the leaves of peach increased with salinity, whereas Cl in peach roots was not affected. Leaves of peach contained higher amounts of Cl than the leaves of plum. The opposite trend was observed in the roots.Sodium content (Na) increased with salinity in plum, whereas in peach it was not affected.The effect of salinity on calcium content (Ca) was not consistent in plum and peach.Potassium content (K) in the leaves of plum and peach decreased with salinity, whereas in the roots it was not affected.The Ca/K ratio in plum leaves increased with salinity, whereas in peaches it decreased in the 4000 p.p.m. treatment.Leaf phosphorus content (P) in the plum and the ‘Balady’ peach decreased with salinity, while in ‘Mit Ghamre’ peach it was not consistently affected. In plum root, P increased with salinity, whereas the effect was the opposite in peach.Magnesium content (Mg) was not significantly affected.The depth of the water table had no consistent effect on the Cl, Na, Ca, K, Ca/K ratio, P and Mg contents in the leaves and roots of plum or peach.The interaction between salinity treatments and water table levels was not significant in most cases. 相似文献
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本文针对我国水利水电专业实践教学存在的缺乏对实习的正确认识、学生缺少实践的机会、知识掌握不牢、实习经费严重不足、学生对实习兴趣不大以及仿真实习系统少，实习设备老化等问题，提出了要正确认识大学生实习、合理安排实践教学、建立开放的实践教学体系、建立校企合作实习基地、激发学生实践热情、改善实践教学设备，增加仿真操作训练等对策。 相似文献
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采用透射电子显微镜、组织化学和荧光显微镜相结合的方法对华南忍冬（Lonicera confusa DC.）不同发育阶段的花结构差异及其绿原酸积累规律进行系统分析。结果显示：随着花的发育,花冠筒叶绿体结构逐渐完善并积累淀粉粒,幼蕾期叶绿体已有基粒和基粒片层出现,但没有明显的淀粉粒出现;绿蕾期叶绿体结构完整,积累有一至数个淀粉粒;白蕾期叶绿体数量少,含有丰富的淀粉粒;银花期和金花期叶绿体极少;花冠筒木质部导管细胞壁逐渐木质化加厚。在花冠筒中,幼蕾期和绿蕾期绿原酸含量丰富;白蕾期薄壁细胞内绿原酸含量开始减少,维管束仍积累较多的绿原酸;银花期和金花期薄壁细胞绿原酸含量进一步减少且分散分布,维管束累积的绿原酸也减少,主要分布在木射线中。在花萼筒-子房中,不同发育阶段,其薄壁细胞、维管束、中轴胎座和胚珠都有绿原酸分布。表明绿原酸可能在叶绿体内合成,然后转至细胞液中聚合,最后在液泡内积累;叶绿体中淀粉粒数量与绿原酸合成呈负相关。 相似文献
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覆膜和钾肥对马铃薯铁素吸收分配的影响 总被引：2，自引：0，他引：2
通过田间试验研究了覆膜和钾肥对马铃薯不同生育时期体内铁的浓度、吸收累积量及其分布的影响.结果表明:马铃薯全株、叶、茎、块茎中铁的浓度从苗期到成熟期呈波浪式变化;铁的累积量在整个生育时期呈现先增大后减小的变化规律,均在块茎膨大期达到峰值;而铁素在马铃薯体内的分布情况表现为:前4个时期在各个器官中分布的顺序为叶＞茎＞块茎,到成熟期表现为茎＞叶＞块茎.覆膜对叶中铁的分布有减小的作用,即它能增大茎和块茎中铁的分布,随着生育时期的向前推进,块茎中铁的分布明显增大,它对块茎中铁的累积也有一定的增大效果;钾肥在成熟期之前的一段时间内能在一定程度增大铁在块茎中的分布,但是此二因素对马铃薯体内铁的影响作用均未达到一定的显著水平. 相似文献