渗透胁近下小麦的膜损伤与ABA增高的关系

以渗透势为－０．６７ＭＰａ的ＰＥＧ根际处理小麦幼苗，在２４ｈ胁迫期间，叶片相对含水量（ＲＷＣ）和叶绿素含量下降，质膜透性于１８ｇ迅速升高，丙二醛（ＭＤＡ）含量在１２ｈ后急剧增加，超氧化物歧化酶（ＳＯＤ）活性下降，过氧化物酶（ＰＯＤ）活性升高；而ＡＢＡ含量在胁迫处理下的３ｈ和１５ｈ出现两个高峰。表明渗透胁迫下ＡＢＡ的积累在膜损伤之前。     

渗透胁迫下小麦的膜损伤与ABA增高的关系

以渗透势为－０．６７ＭＰａ的ＰＥＧ根际处理小麦幼苗，在２４ｈ胁迫期间，叶片相对含水量（ＲＷＣ）和叶绿素含量下降，质膜透性于１８ｈ迅速升高，丙二醛（ＭＤＡ）含量在１２ｈ后急剧增加，超氧化物歧化酶（ＳＯＤ）活性下降，过氧化物酶（ＰＯＤ）活性升高；而ＡＢＡ含量在胁迫处理下的３ｈ和１５ｈ出现两个高峰．表明渗透胁迫下ＡＢＡ的积累在膜损伤之前．     

渗透胁迫对甘薯叶绿体超微结构及其膜脂过氧化的影响

用不同浓度的ＰＥＧ对甘薯进行根际渗透胁迫处理，研究了对叶绿体超微结构和膜脂过氧化的影响．结果表明，经不同浓度的ＰＥＧ渗透胁迫２４ｈ后，叶片细胞质膜透性、ＭＤＡ含量增加，ＣＡＴ活性升高；ＳＯＤ活性表现出品种抗旱适应特性．相同的渗透胁迫条件对抗旱性较强的渝薯２０的超微结构破坏明显小于抗旱性较弱的农大红．试验结果综合阐明了由渗透胁迫引发的活性氧累积对甘薯叶绿体膜结构具有强烈的损伤作用     

抗坏血酸对黄瓜种子荫发及组培苗生长的影响

抗坏血酸对黄瓜种子荫发及组培苗生长的影响孙艳，崔鸿文，尹明安，张恩让（西北农业大学园艺系，陕西杨陵，７１２１００）ＴＨＥＥＦＦＥＣＴＳＯＦＡＣＣＯＲＢＩＣＡＣＩＤＯＮＣＵＣＵＭＢＥＲＳＥＥＤＳＧＥＲＭＩＮＡＴＩＯＮＡＮＤＴＨＥＧＲＯＷＴＨＯＦＪＩＮ４...     

生化黄腐酸（BcFA）浸种对小麦幼苗生长及干旱时的生理影响

生化黄腐酸（ＢｃＦＡ）浸种对小麦幼苗生长及干旱时的生理影响杨晓玲（河北农业技术师范学院园艺系，昌黎，０６６６００）ＴＨＥＥＦＦＥＣＴＯＦＢＩＯＣＨＥＭＩＣＡＬＦＵＬＶＩＣＡＣＩＤ（ＢｃＦＡ）ＯＮＴＨＥＧＲＯＷＴＨＯＦＷＮＥＡＴＳＥＥＤＬＩＮＧＡＮＤＳ...     

联想与一题多解

丰富的联想 ,能使思维富有创造性 ,使解题方法具有多样性。现举例说明。例　如图 1 ,在△ＡＢＣ中 ,∠Ｃ =90°,∠Ａ的平分线ＡＤ交ＢＣ于Ｄ。求证 :ＡＣ2ＡＤ2 =ＢＣ2ＢＤ 。联想之一 :由结论左边联想射影定理 ,因图中没有射影定理基本图形 ,于是作辅助线补全射影定理的基本图形 ;由结论右边联想辅助平行线及中点 ;由已知角平分线联想有关角平分线的基本图形。由此可产生两种证法。证法一 :如图 2 ,过点Ｃ作ＣＥ⊥ＡＤ于Ｅ交ＡＢ于Ｆ ,再过Ｅ作ＥＧ∥ＢＣ交ＡＢ于Ｇ。ＡＤ平分∠ＣＡＢ ∠ 1 =∠ 2ＡＤ ⊥ＣＥ ∠ＡＥＣ =∠ＡＥＦＡＥ =Ａ…     

绿丰收对小白菜生长及产量的影响(简报)

绿丰收对小白菜生长及产量的影响（简报）朱京涛１黄云祥２（１河北农业技术师范学院园艺系，２黄腐酸研究所，昌黎，０６６６００）ＴＨＥＩＮＦＬＵＥＮＣＥＯＦＬＵＦＥＮＧＳＨＯＵＯＮＴＨＥＧＲＯＷＴＨＡＮＤＹＩＥＬＤＯＦＳＭＡＬＬＣＨＩＮＥＳＥＣＡＢＢＡＧＥ...     

光周期对水分胁迫下冬小麦幼苗内源ABA及CTK含量的影响

全光照促进水分胁迫下冬小麦幼苗根ＡＢＡ及ＣＴＫ的累积。正常光周期则促进叶片ＣＴＫ的累积，对叶片ＡＢＡ累积影响较小。     

MAGNETIC RELAXATION AT EARLY TIMES AND FLUX DIFFUSION BARRIER V（J，B，T） FOR Ti－1223 DOPED WITH Pb AND Ba BY COMPLEX AC SUSCEPTIBILITY MEASUREMENTS

ＭＡＧＮＥＴＩＣＲＥＬＡＸＡＴＩＯＮＡＴＥＡＲＬＹＴＩＭＥＳＡＮＤＦＬＵＸＤＩＦＦＵＳＩＯＮＢＡＲＲＩＥＲＶ（Ｊ，Ｂ，Ｔ）ＦＯＲＴｉ－１２２３ＤＯＰＥＤＷＩＴＨＰｂＡＮＤＢａＢＹＣＯＭＰＬＥＸＡＣＳＵＳＣＥＰＴＩＢＩＬＩＴＹＭＥＡＳＵＲＥＭＥＮＴＳＤ...     

THE GENERAL CATEGORICAL CLASSES BP_N AND THEIR COMPLETENESS

ＴＨＥＧＥＮＥＲＡＬＣＡＴＥＧＯＲＩＣＡＬＣＬＡＳＳＥＳＢＰ_ＮＡＮＤＴＨＥＩＲ　ＣＯＭＰＬＥＴＥＮＥＳＳＴＨＥＧＥＮＥＲＡＬＣＡＴＥＧＯＲＩＣＡＬＣＬＡＳＳＥＳＢＰ＿ＮＡＮＤＴＨＥＩＲＣＯＭＰＬＥＴＥＮＥＳＳ￥ＳｕｎＨｕｉｃｈｅｎｇ；ＬｕＹｉｚｈｏ?..     

Protein phosphorylation is involved in the water stress-induced ABA accumulation in the roots ofMalus hupehensis Rehd

Water stress-induced ABA accumulation plays a key role in the root to shoot communication and/or the cell to cell signaling under the soil stresses. The signaling of the water stress itself that leads to the accumulation, however, is less known. In this study, we subjected the roots of Malus hupehensis seedlings to water stress treatment and investigated the ABA accumulation in relation to protein phosphorylation. Our results showed that ABA accumulation could be substantially triggered in 40 min and reached 4 folds in 100 min after treatment with 30% PEG 6000 (polyethylene glycol). The water stress treatment also led to a substantial enhancement of total kinase activity, assessed with histone-Ⅲ as substrate, in 15 min and a maximum enhancement in 30 min before it declined to initial level. The Ca²⁺-dependent kinase activity showed a similar, if not more sensitive, trend. When the roots were fed with labeled ³²P- ATP, water stress enhanced the labeling of proteins, which showed a maximum labeling at 40 min. Two inhibitors of protein kinases, Quercetin and H7, effectively diminished or completely blocked the ABA accumulation under the stress treatment. It is therefore suggest that protein phosphorylation is involved in the signaling of the water stress-induced ABA accumulation.     

Roles of a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism in ABA signal production in Arabidopsis

ABA, acting as a stress signal, plays crucial roles in plant resistance to water stress. Because ABA signal production is based on ABA biosynthesis, the regulation of NCED, a key enzyme in the ABA biosynthesis pathway, is normally thought of as the sole factor controlling ABA signal production. Here we demonstrate that ABA catabolism in combination with a synergistic regulation of ABA biosynthesis plays a crucial role in governing ABA signal production. Water stress induced a significant accumulation of ABA, which exhibited different patterns in detached and attached leaves. ABA catabolism followed a temporal trend of exponential decay for both basic and stress ABA, and there was little difference in the catabolic half-lives of basic ABA and stress ABA. Thus, the absolute rate of ABA catabolism, i.e. the amount of ABA catabolized per unit time, increases with increased ABA accumulation. From the dynamic processes of ABA biosynthesis and catabolism, it can be inferred that stress ABA accumulation may be governed by a synergistic regulation of all the steps in the ABA biosynthesis pathway. Moreover, to maintain an elevated level of stress ABA sustained activation of NCED3 should be required. This inference was supported by further findings that the genes encoding major enzymes in the ABA biosynthesis pathway, e.g. NCED3, AAO3 and ABA3 were all activated by water stress, and with ABA accumulation progressing, the expressions of NCED3, AAO3 and ABA3 remained activated. Data on ABA catabolism and gene expression jointly indicate that ABA signal production is controlled by a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism.     

PEG处理下葡萄试管苗脯氨酸及内源ABA含量变化的研究

用不同浓度的PEG处理全球红葡萄生根试管苗，造成一定程度的水分亏缺，观察葡萄试管苗在水分胁迫下的生理反应。结果表明：PEG处理导致葡萄试管苗脯氨酸的积累和内源ABA的迅速增加。6％PEG胁迫处理66h时脯氨酸含量达到高峰，72h又有所下降；而3％PEG胁迫处理脯氨酸含量仍保持持续上升趋势。内源ABA在12h内达到第一个峰值，含量为对照的两倍多，并维持比对照略高的水平；而6％PEG胁迫处理植株在48h时ABA再次积累，含量比对照高100多倍。     

植物在水分胁迫下脯氨酸积累的研究──Ⅲ．外源脱落酸、细胞分裂素与脯氨酸积累和叶气孔变化的关系

研究了在水分胁迫下，两种禾草体内ＰＲＯ、叶气孔、外源ＡＢＡ和６－ＢＡ之间的相互依存关系。认为ＰＲＯ积累中气孔因子能更早的提示ＰＲＯ变化的态势。外源ＡＢＡ，６－ＢＡ及水分胁迫仅仅是促使气孔变化的初级因子。     

Responses of ABA and CTK to soil drought in leafless and leafy apple tree

The authors tested the contents of ABA (abscisic acid), ZR (zeatin riboside), DHZR (dihydrozeatin riboside) and iPA (isopentenyl adenosine) in leafless and leafy apple trees (Red Fuji/Malus micromalus Makino) during soil drought stress. ABA concentration in drought stressed leafless trees increased significantly compared to the controls. ABA both in roots and xylem rose steadily in the earlier drought stage, reaching a maximum of 1.46 +/- 0.35 nmol g(-1) FW and 117 nmol l(-1) after the 8th day. Similar change patterns of ABA concentration was observed in the leafy trees during soil drought stress; ABA concentrations in roots and xylem sap increased and reached the maximum in the first three days; after 8th day, it decreased slightly, whereas leaf ABA concentration increased steadily in drought stressed plants throughout the duration of the experiment. Between drought stressed and control trees, no significant differences were observed in concentration of ZR and DHZR in both leafless and leafy trees; whereas iPA concentration of the drought stressed leafless and leafy plants decreased markedly in the later stage of drought. These results showed that endogenous ABA originated mainly from the roots in the earlier drought stage, and mainly from the leaves in the later drought stage. Total CTK showed no reduction in the earlier drought stage and decreased in the later drought stage.     

水杨酸对水分胁迫下菜豆若干生理指标的影响

考察了外源水杨酸处理对水分胁迫下菜豆幼苗叶片的含水量、光合色素含量、电解质外渗率及SOD、POD、CAT活性和根的电解质外渗率及SOD、POD、CAT活性的影响．结果表明：外源水杨酸能减缓水分胁迫下菜豆幼苗叶片含水量和光合色素含量的下降，保持叶片的SOD、CAT和根的SOD、POD、CAT活性，但却增加了叶片和根的电解质外渗率，降低了叶片POD的活性．由此看出，水杨酸可以在一定程度上够缓解水分胁迫对菜豆幼苗造成的伤害．     

Protein tyrosine phosphatase is possibly involved in cellular signal transduction and the regulation of ABA accumulation in response to water deficit in Maize L.coleoptile

Water deficit-induced ABA accumulation is an ideal model or “stimulus-response”system to investigate cellular stress signaling in plant cels,using such a model the cellular stress signaling triggered by water deficit was investigated in Maize L.coleoptile.Water deficit-induced ABA accumulation was sensitively blocked by NaVO3,a potent inhibitor both to plasma membrane H^ -ATPase(PM-H^ -ATPase)and protein tyrosine phosphatase(PTPase).However,while PM-H^ -ATPase activity was unaffected under water deficit and PM-H^ -ATPase activator did not induce an ABA accumulation instead of water deficit,water deficit induced an increase in the protein phosphatase activity,and furthermore,ABA accumulation was inhibited by PAO,a specific inhibitor of PTPase.These results indicate that protein phosphtases may be involved in the cellular signaling in response to water deficit.Further studies identifiled at least four species of protein phosphtase as assayed by using pNPP as substrate,among which one component was especially sensitive to NaVO3.The NaVO3-sensitive enzyme was purified and finally showed a protein band about 66kD on SDS/PAGE.The purified enzyme showed a great activity to some specific PTPase substrates at pH 6.0.In addition to NaVO3,the enzyme was also sensitive to some other PTPase inhibitors such as Zn^2 and MO3^3 ,but not to Ca^2 and Mg^2 ,indicating that it might be a protein tyrosine phosphatase.Interestingly,the purified enzyme could be deactivated by some reducing agent DTT.which was previously proved to be an inhibitor of water deficit-induced ABA accumulation.This result further proved that PTPase might be involved in the cellular signaling of ABA accumulation in response to water deficit.     

ABA和GA刺激的ROS代谢调节水稻幼根伸长分析

本文探索水稻幼根生长过程中ABA和GA对ROS代谢的影响,结果显示:低于0.5μmol/L的ABA促进根伸长,超过此浓度的ABA抑制根伸长;H2O2与ABA相似,低浓度促进而高浓度抑制;在观察浓度范围内,GA促进根伸长.利用3,3'-二氨基联苯胺(diaminobenzidine,DAB)组织化学染色方法检测根尖部位H2O2代谢情况,结果显示,对照、ABA,GA和ABA+GA处理后,根尖分别呈现浅黄色、深棕色、黄色和深棕色,说明ABA比GA诱导较多H2O2产生.进一步研究发现,ABA和ABA+GA分别上调过氧化物酶(peroxidase,POD)活性13.4%和8.37%,GA下调POD活性19.0%;同时,ABA和ABA+GA处理分别下调过氧化氢酶(catalase,CAT)活性14.8%和16.3%,GA则上调CAT活性5.16%.以上结果表明,ABA可能通过上调POD和抑制CAT活性来提高ROS含量,而GA与之相反,严谨控制ROS浓度,促进水稻生长.     

冬小麦农艺性状对花前水分胁迫的响应

 为研究冬小麦对花前水分胁迫的响应,在大田条件下,以济麦20为材料,设置正常水分(CK)、中度干旱(MD)和重度干旱(SD)三个水分处理进行试验。水分胁迫下,冬小麦春季分蘖减少,有效分蘖比例增加,叶面积、株高和物质累积量等均减小,生长过程受阻。叶面积变化主要由叶片长度的减小引起,且对旗叶影响程度低于低位叶;株高的降低主要是第IV、第V高位节间长度的降低,第I、第II低位节间反而有所增长;次生根发生减少,通过减少根密度及增加根长适应干旱;物质积累因水分胁迫而受阻,且物质向根系的分配增加,根冠比增大。水分胁迫下,冬小麦花前生长发育受阻,地上部通过减小生长量适应水分胁迫,降低幅度随胁迫加剧而增大;根系在减少发生的同时,增加根长,扩大吸收面积。