氮素形态对小麦花后不同器官内源激素含量的影响

采用盆栽方法,研究了酰胺态氮、铵态氮和硝态氮对小麦(Triticum aestivum)花后根系、旗叶和籽粒内源激素IAA、GA₃、ABA和ZR含量的影响。结果表明,小麦不同器官的内源激素含量对3种氮素形态的响应不同。氮素形态调节籽粒灌浆是通过根系、旗叶和籽粒中内源激素的协同作用而实现的。酰胺态氮与硝态氮处理相比,小麦花后5~15 d,旗叶GA₃含量、籽粒IAA和ABA含量较高,籽粒灌浆速率(Grain-filling rate, GFR)较高;花后15~25 d,根系GA₃含量、旗叶IAA和GA₃含量、籽粒ABA含量较高,籽粒IAA含量较低,GFR较低。铵态氮与硝态氮处理相比,小麦花后5 d,籽粒ZR含量较高;花后15 d前后,籽粒IAA、ABA含量较低,GFR较低;花后20~25 d,根系ZR、GA₃含量较低,旗叶IAA、GA₃含量较低,ABA含量较高,籽粒ABA、GA₃含量较低,IAA含量较高,GFR较高。铵态氮比硝态氮处理的小麦籽粒粒重显著增加。铵态氮和酰胺态氮处理比硝态氮处理增产显著。建议在‘豫麦49’施肥时,使用铵态氮或酰胺态氮并配施硝化抑制剂。     

大果白刺种子内源激素含量研究

目的：探究大果白刺种子萌发过程中内源激素的变化。方法：通过HPLC测定低温层积后大果白刺种子内源激素含量的变化。结果：大果白刺种子GA₃含量显著提高，而ABA、IAA、ZR和ETH含量均显著下降。GA₃/ABA值显著提升，IAA/ABA和ZR/ABA值呈现下降趋势。结论：GA₃含量和GA₃/ABA值较高，ABA、IAA、ZR、ETH含量和IAA/ABA、ZR/ABA值较低，证明各种内源激素含量及其比值是制约其种子休眠的重要因素。     

不同栽培措施对降香黄檀内源激素含量的影响

为了了解不同栽培措施对降香黄檀叶片内源激素的影响,本研究通过铺设修枝、移植、钾肥、乙烯4个试验,分析各处理叶片激素含量特征。结果表明：修枝实验中,重度修枝处理IAA、GA₃、ZR、ABA含量均最大,分别为69.849、6.619、8.805、77.998 ng·g^-1。移植各处理中,去冠移处理IAA、ZR含量最高分别为73.195和9.472 ng·g^-1,而其ABA含量最低为52.001 ng·g^-1,GA₃含量最高的为断根处理8.418 ng·g^-1。IAA、ZR、GA₃含量K1钾肥配比最高分别为75.188、8.383、6.127 ng·g^-1;ABA最大含量71.082 ng·g^-1为CK处理。乙烯试验中,CK处理的IAA、GA₃含量最高分别为47.762、4.967 ng·g^-1;E2.5%处理的ABA含量96.94 ng·g^-1最高。E0.1%处理的ZR含量最高为9.378 ng·g^-1。修枝对GA₃/ABA和ZR/GA₃影响较大,其最小值分别比最大值降低了29.7%、19.0%。移植对IAA/ABA、GA₃/ABA影响较大,最小值比最大值依次降低了52.47%和51.47%。树干注射乙烯和钾肥对IAA/ABA、GA₃/ABA影响较大,乙烯试验最小值分别比最大值降低了55.4%、49.2%,钾肥试验最小值分别比最大值降低了48.8%和37.1%。     

四季花金花茶花芽分化进程及叶片内源激素变化

四季花金花茶(Camellia perpetua)为山茶属中唯一几乎全年开花的珍稀濒危植物。为探究其花芽分化进程及不同花发育时期和年生长周期叶片内源激素变化,该研究通过石蜡切片,观察四季花金花茶花芽分化进程,采用酶联免疫吸附法测定不同花发育时期叶片及年生长周期内有花芽和无花芽叶片的脱落酸(ABA)、吲哚乙酸(IAA)、赤霉素(GA₃)和玉米素核苷(ZR)含量的变化规律。结果表明：(1)四季花金花茶花芽分化顺序由外向内进行,分为6个时期,共历时35 d,从花芽分化至开花约2个月。(2)花芽形态分化期叶片ABA、GA₃的含量及GA₃/ABA、(IAA+GA₃)/ZR的比值较高,IAA、ZR的含量及IAA/ABA、ZR/ABA的比值较低。(3)年生长周期内有花芽叶片ABA、IAA、ZR的含量整体上高于无花芽叶片;IAA/ZR及(IAA+GA₃)/ZR的比值整体上低于无花芽叶片。综上表明,四季花金花茶花芽分化至开花时间较短;高水平的ABA、GA₃及低水平的IAA、...     

外源GA3和ABA对红肉脐橙果实品质的影响

以生长一致的红肉脐橙成年植株为试材,研究了果实转色前外源GA₃和ABA处理对果实品质的影响。结果表明,外源GA₃处理提高了果皮亮度,但降低了果皮红色度、黄色度和单果重;ABA处理提高了果皮红色度,但降低了果皮亮度;GA₃100mg/L处理虽然极显著降低了果皮厚度,极显著提高了果皮亮度、可溶性固形物和VitC含量,但同时极显著降低了果皮红色度、糖酸比,并极显著提高了果实含酸量;外源ABA处理还极显著降低了果实可食率、出汁率和VitC含量。因此,在果实转色前用外源GA₃和ABA处理红肉脐橙果实均不利于其综合品质的提高。     

刺楸种子层积过程中内源植物激素的动态变化及激素在种子休眠中的作用

本文主要以高效液相色谱为主要手段,结合生物测定方法,测定了4种不同层积条件下激素动态变化。结果表明刺楸干种子中存在有两种抑制物质-脱落酸(ABA)和香豆素(C),在种子层积的不同阶段又相继有GA₃,IAA和Z出现,并在层积后熟过程中呈现非常有规律的变化。根据激素的变化,可把种子整个后熟过程分三个阶段;即阶段Ⅰ,以抑制物质(ABA,C)和IAA水平迅速减少为主要特征,阶段Ⅱ主要表现为GA₃和Z合量的上升,阶段Ⅲ各种激素处于相对稳定的状态。种子的休眠与否可能主要取决于阶段Ⅱ的状况。在刺楸种子胚形态后熟期间,胚的生长与分化同ABA和C水平有很高的相关性,但同时也受GA₃和IAA的调节。生理后熟主要与Z有关,同ABA和C无明显相关性。同时本文还对激素相对水平做了初步研究,发现GA₃/ABA+IAA,Z/GA₃+IAA和GA₃/C+IAA^*,在种子后熟期间的变化同胚生长发育存在高度的一致性。认为激素的相对水平对种子休眠起重要的控制作用,还推测激素的作用可能类似于"板机"机制。     

3,4-二羟基苯乙酮胁迫对天山云杉种子萌发过程中内源植物激素含量变化的影响

3,4-二羟基苯乙酮(DHAP)是天山云杉(Picea schrenkiana ssp. tianschanica)叶和凋落物中存在的主要自毒物质, 是导致天山云杉林天然更新障碍的原因之一。为了解释自毒物质发生作用的生理机制, 该文设计多个浓度梯度的DHAP溶液处理天山云杉种子, 以发芽率和发芽势为种子萌发参数, 运用反相超高效液相色谱(UPLC)分析技术, 检测了种子萌发过程中内源植物激素玉米素(ZT)、赤霉素(GA₃)、吲哚乙酸(IAA)和脱落酸(ABA)含量水平的变化。研究结果表明: DHAP处理对天山云杉种子萌发影响具有浓度效应, 表现为5.0 mmol·L^-1 > 0.1 mmol·L^-1 > 1.0 mmol·L^-1 >对照, 即5.0 mmol·L^-1 DHAP处理组对种子萌发的抑制作用最强、0.1 mmol·L^-1 DHAP处理组次之、1.0 mmol·L^-1 DHAP处理组最弱; DHAP处理组的种子内源ZT、GA₃浓度水平降低, ABA含量升高, GA₃浓度峰值出现时间延迟, IAA浓度在高浓度(5.0 mmol·L^-1 DHAP)处理组短时间内(3-6天)过量积累, 1.0和5.0 mmol·L^-1 DHAP处理组的种子内源ABA浓度峰值出现时间延迟; DHAP处理种子萌发1-6天时, ZT/(GA₃+IAA)比值降低, IAA/ZT、ABA/ZT比值增大; ABA/(ZT + GA₃ + IAA)比值在0.1 mmol·L^-1 DHAP处理组增大, 在5.0 mmol·L^-1 DHAP处理组降低。DHAP处理引发种子内源激素含量水平及激素含量间比值变化, 可能是抑制、延迟天山云杉种子萌发的主要原因。     

光质对设施葡萄叶片衰老与内源激素含量的影响

以设施延迟栽培条件下叶片衰老速度不同的意大利和无核白鸡心2个葡萄品种为试材,分别进行补充红光和蓝光处理,研究不同光质对叶片衰老过程中叶绿素含量、净光合速率和内源激素含量的影响.结果表明: 与未补光对照相比,红光能够显著提高叶片的叶绿素含量和净光合速率,降低了内源赤霉素(GA₃)含量,但明显减缓了脱落酸(ABA)含量的增加和玉米素核苷(ZR)总含量的减少,从而显著提高了(GA₃+ZR)/ABA值,延缓叶片衰老.叶片衰老前期,蓝光处理叶片叶绿素含量、净光合速率和(GA₃+ZR)/ABA值均低于对照,加速了植株的衰老进程;但在叶片衰老后期,蓝光处理叶绿素含量、净光合速率和(GA₃+ZR)/ABA值逐渐高于对照,在一定程度上延缓了叶片衰老.植物内源激素生长素(IAA)则表现出叶片衰老前期促进叶片生长发育、叶片衰老后期加速衰老的双重作用.意大利叶片衰老速度较无核白鸡心慢.在本试验条件下,红光处理效果最好,有效延缓了叶片衰老进程,延长了叶片的生理功能期.     

单花、有侧花牡丹品种花芽分化特点及内源激素变化

为比较单花牡丹品种‘梨花粉’、有侧花牡丹品种‘姊妹游春’和‘云鄂粉’的花芽分化进程、形态特征差异及花芽分化期内源激素的变化,该研究通过解剖和石蜡切片,观察‘梨花粉’‘姊妹游春’和‘云鄂粉’的花芽分化过程,采用酶联免疫吸附分析法测定不同分化阶段‘梨花粉’和‘姊妹游春’的生长素(IAA)、脱落酸(ABA)、赤霉素(GA₃)及玉米素核苷(ZR)的含量。结果表明：(1)‘梨花粉’花芽分化仅6个时期;有侧花品种‘姊妹游春’和‘云鄂粉’花芽分化为11个时期,顶花原基先分化,侧花原基后分化。(2)叶原基分化期至苞片原基分化期,‘姊妹游春’和‘梨花粉’花芽中ABA、GA₃及ZR的含量均升高,IAA含量降低;‘姊妹游春’侧花原基分化起始阶段,ABA、GA₃含量降低,ZR、IAA含量升高。(3)‘梨花粉’ABA/IAA比值在形态分化期时最低。综上认为,有侧花牡丹品种花芽分化比单花牡丹品种早,分化时间长,顶花和侧花部分花器官分化期重叠;较高水平的ZR、IAA以及较低的ABA、GA₃有利于启动侧花原基分化。该研究结果为牡丹...     

温水浸种对杜仲种子萌发过程中保护酶活性及内源激素含量变化的影响

探讨杜仲（Eucommia ulmoides Oliver）种子萌发过程中保护酶活性及内源激素含量的变化，为其种子破眠及萌发不同时期采取有效处理措施，从而提高出苗率提供参考。利用室温（CK）、40℃、50℃、60℃和70℃不同水温，探讨温水浸种对杜仲种子萌发的影响。种子萌发进程中，利用常规生理生化方法测定种子内超氧化物歧化酶（SOD）、过氧化物酶（POD）活性和丙二醛（MDA）含量，以及酶联免疫法测定赤霉素（GA₃）、吲哚乙酸（IAA）、脱落酸（ABA）和玉米素核苷（ZR）含量。结果表明：①温水浸种处理能提高了杜仲种子的发芽率及发芽势，其中以50℃温水处理最为显著。②与室温浸种处理相比，50℃温水浸种处理提高了种子内SOD及POD活性，减轻了质膜氧化损伤程度，致使MDA含量的持续下降，从而促使种子朝向有利于萌发的方向发展。此外，50℃温水浸种处理在提高种子内促进生长内源GA₃、IAA及ZR含量的同时，并降低了抑制生长的内源ABA含量，致使GA₃/ABA、IAA/ABA和ZR/ABA值均明显高于室内浸种处理，最终促进了杜仲种子的萌发。     

Regulation of dormancy in barley by blue light and after-ripening: effects on abscisic acid and gibberellin metabolism

White light strongly promotes dormancy in freshly harvested cereal grains, whereas dark and after-ripening have the opposite effect. We have analyzed the interaction of light and after-ripening on abscisic acid (ABA) and gibberellin (GA) metabolism genes and dormancy in barley (Hordeum vulgare 'Betzes'). Analysis of gene expression in imbibed barley grains shows that different ABA metabolism genes are targeted by white light and after-ripening. Of the genes examined, white light promotes the expression of an ABA biosynthetic gene, HvNCED1, in embryos. Consistent with this result, enzyme-linked immunosorbent assays show that dormant grains imbibed under white light have higher embryo ABA content than grains imbibed in the dark. After-ripening has no effect on expression of ABA biosynthesis genes, but promotes expression of an ABA catabolism gene (HvABA8'OH1), a GA biosynthetic gene (HvGA3ox2), and a GA catabolic gene (HvGA2ox3) following imbibition. Blue light mimics the effects of white light on germination, ABA levels, and expression of GA and ABA metabolism genes. Red and far-red light have no effect on germination, ABA levels, or HvNCED1. RNA interference experiments in transgenic barley plants support a role of HvABA8'OH1 in dormancy release. Reduced HvABA8'OH1 expression in transgenic HvABA8'OH1 RNAi grains results in higher levels of ABA and increased dormancy compared to nontransgenic grains.     

Multiple actions of abscisic acid in senescence of oat leaves

The modifications induced by abscisic acid (ABA) on the senescence of oat leaves in darkness have been studied and are compared with its well-known effects in light. Contrary to the action in light, ABA preserves chlorophyll (Chl) in the dark almost as well as kinetin. Chlorophylla is decolorized more extensively thanb, and the content ofb is maintained by ABA almost at its initial level for 4 days. ABA also prevents proteolysis in darkness just as completely as chlorophyll loss, the relationship of both breakdown processes to ABA concentration being strictly log-linear over the range from 1 to 100 M. In line with this action, ABA inhibits formation of the neutral protease in the dark but not in the light. The data suggest that ABA and kinetin operate to preserve chlorophyll and protein by different mechanisms, since their actions are neither independent nor synergistic but actually interfere with one another. In this connection, protein values given by the Lowry and Bradford methods have been compared. In parallel with the effect on senescence, ABA slowly opens the stomata in the dark. This effect increases with time, and by day 3 the stomata in ABA are as open as in leaves on water in light. Thus all these effects of ABA in darkness are strikingly opposite to those commonly observed on leaves in natural lighting. In addition, ABA powerfully inhibits the formation of ethylene in the dark by the detached oat leaves, and this inhibition also tends to increase with time. Finally, a slight antagonism to ABA's action on senescence is exerted byp-coumaric acid in the light but not in the dark.     

Uniconazole-induced tolerance of rape plants to heat stress in relation to changes in hormonal levels, enzyme activities and lipid peroxidation

Winter rape (Brassica napus L. cv. 601) seedlings were treated with 50 mg.l-1of foliar-applied uniconazole and then exposed to heat stress with a light/dark temperature regime of 43 °C/38 °C for 3 days at the stem elongation stage. Heat stressed plants contained lower endogenous GA3, IAA and zeatin contents than the controls, while ABA content and ethylene level were increased significantly. Uniconazole-treated plants had lower endogenous GA3 and IAA contents, and higher zeatin and ABA contents and ethylene levels. Leaf chlorophyll content and respiratory capacity of roots were reduced markedly after plants were subjected to heat stress, and foliar sprays of uniconazole retarded the degradation of chlorophyll and increased respiratory capacity of roots. Following exposure to heat, the activities of superoxide dismutase and peroxidase were significantly reduced. Uniconazole-induced heat tolerance was accompanied by increased activities of various antioxidant enzymes. Foliar applications of uniconazole reduced electrolyte leakage and malondialdehyde accumulation caused by heat stress, suggesting that uniconazole may have decreased heat-induced lipid peroxidation and membrane damage. Foliar sprays of uniconazole increased the tolerance of rape plants to heat stress.     

Uniconazole-induced alleviation of freezing injury in relation to changes in hormonal balance, enzyme activities and lipid peroxidation in winter rape

Winter rape (Brassica napus L. cv. 601) seedlings were treated with 50 mg.l-1 of foliar-applied uniconazole and then exposed to freezing stress with a light/dark temperature regime of 2 °C/–3 °C for 5 days at the seedling stage. Stressed plants contained lower endogenous GA3 and IAA contents than the controls, while zeatin and ABA contents and ethylene levels were significantly increased. Uniconazole-treated plants had lower endogenous GA3 and IAA contents, and higher zeatin and ABA contents and ethylene levels. Leaf chlorophyll content and respiratory capacity of roots were reduced significantly after plants were subjected to freezing stress, and foliar sprays of uniconazole retarded the degradation of chlorophyll and increased respiratory capacity of roots. Uniconazole-induced freezing tolerance was accompanied by increased activities of various antioxidant enzymes, including superoxide dismutase, catalase and peroxidase. Foliar applications of uniconazole reduced electrolyte leakage and malondialdehyde accumulation caused by freezing stress, suggesting that uniconazole may have decreased freezing-induced lipid peroxidation and membrane damage.     

Inhibition of germination of dormant barley (Hordeum vulgare L.) grains by blue light as related to oxygen and hormonal regulation

Germination of primary dormant barley grains is promoted by darkness and temperatures below 20 °C, but is strongly inhibited by blue light. Exposure under blue light at 10 °C for periods longer than five days, results in a progressive inability to germinate in the dark, considered as secondary dormancy. We demonstrate that the inhibitory effect of blue light is reinforced in hypoxia. The inhibitory effect of blue light is associated with an increase in embryo abscisic acid (ABA) content (by 3.5‐ to 3.8‐fold) and embryo sensitivity to both ABA and hypoxia. Analysis of expression of ABA metabolism genes shows that increase in ABA mainly results in a strong increase in HvNCED1 and HvNCED2 expression, and a slight decrease in HvABA8′OH‐1. Among the gibberellins (GA) metabolism genes examined, blue light decreases the expression of HvGA3ox2, involved in GA synthesis, increases that of GA2ox3 and GA2ox5, involved in GA catabolism, and reduces the GA signalling evaluated by the HvExpA11 expression. Expression of secondary dormancy is associated with maintenance of high embryo ABA content and a low HvExpA11 expression. The partial reversion of the inhibitory effect of blue light by green light also suggests that cryptochrome might be involved in this hormonal regulation.     

气调和乙烯对梅果叶绿素和内源激素含量的影响

本文研究了在（25±1）℃下,气调包装和乙烯吸收剂处理对采后青梅果实叶绿素含量、内源激素IAA,GA3,ABA含量和乙烯释放量的影响及它们之间的关系。结果表明：气调包装果实叶绿素含量最高,其次是乙烯吸收剂处理的;各处理中气调包装果实的乙烯释放量始终很低,GA3含量较高,IAA和ABA含量则较低;对照果实的则相反,乙烯释放量很高,IAA和ABA含量较高,而GA3含量较低。乙烯吸收剂处理的处于二者之间。气调包装可以维持果实较高的GA3水平,降低ABA含量,保持较高的GA3／ABA值,抑制IAA和乙烯的生成,延缓梅果叶绿素的降解。     

Phytochrome and hormonal control of expansion and greening of etiolated wheat leaves

Summary Unrolling of etiolated wheat leaf segments is stimulated by short periods of exposure to red light. Both gibberellic acid and kinetin will stimulate unrolling in the dark, whereas abscisic acid (ABA) inhibits the unrolling response to these two hormones and to red light. Exposure to 5 minutes of red light leads to a rapid increase in endogenous gibberellin levels in etiolated wheat leaves, and this increase is followed by a rapid decline. Pre-treatment with ABA inhibits the increase in gibberellin levels in response to red light, but the ihibitory effect of ABA on unrolling cannot be ascribed only to its effect on gibberellin levels. Pre-treatment with red light reduces the lag-phase in chlorophyll development when wheat leaf segments are subsequently exposed to white light; the effect of red light may be replaced by pre-treatment with kinetin, but gibberellic acid is relatively ineffective in this respect.     

Contrasting photo- and thermoperiod-induced changes in abscisic acid and lipid contents in leaves of mungbean seedlings

Seedlings of Phaseolus aureus ROXB were grown under 12/12 h light/dark cycles with the light period at 32.5°C and darkness at 10°C (normal conditions N) or with light at 10°C and darkness at 32.5°C (inverse conditions, I). I-conditions affected the level of chlorophyll and carotenoids (very low), monogalactosyldiacylgycerol (low) and phosphatidylinositol (high) in the leaves. Leaves of I-seedlings showed a sharp and durable decline of relative water content during the low temperature phase. For the N-seedlings, loss of water was restricted to the end of this period. The loss of water was accompanied by visible symptoms of wilting at specific times of day. Although the pigment content remained nearly unchanged, ABA content of leaves of both N-and I-seedlings increased during water stress. Upon return to the warm period, ABA level continued to increase after the leaves had regained turgor, this 'after stress'increase being more pronounced in the leaves of I-seedlings. Exogenous application of ABA induced a slight increase in the content of phospholipids in N- and I-leaves and a decrease in free fatty acids, whereas monogalactosyldiacylglycerol content was significantly reduced in N-leaves after application of ABA. Upon transfer of I-plants to 20°C for 12 h during the light period, pigment and chloroplastic lipid content increased rapidly whereas upon a further exposure to 10°C in light, pigments and especially monogalactosyldiacylglycerol were lost. The control of pigment and lipid metabolism and the role of ABA during chilling stress are discussed.     

The Effect of Exogenous ABA on the Resistance to the Chilling Stress in Cucumber Seedlings

In the cucumber seedlings pretreated with ABA under light and dark or additional photosynthetic inhibitor (DCMU) before chilling, the effect and the regulative role of ABA on the chilling resistance of cucumber seedlings were investigated. After the excised cotyledonary discs were floated on 10-6 mol/l ABA solution for 24 h and the seedlings were sprayed by 10-4 mol/1 ABA in light, it has been found that ABA has an effect of the protection against low temperature injury in cucumber seedlings. The results showed that the leakage of electrolytes in cucumber cotyledory discs was decreased. The content of glutathione and the accumulation of MDA content in cotyledon of cucumber seedlings were decreased, and decline of the photosynthesis of the leaves or the quenching of chlorophyll fluorescence were slowed, thus the rate of survival in cucumber seedlings was raised. The effect of these regulation was able to be limited by dark or DCMU.     

Proline level is partly under the control of abscisic acid in canola leaf discs during recovery from hyper-osmotic stress

The relationships between the changes induced in abscisic acid (ABA) and proline contents were investigated in canola ( Brassica napus L.) leaf discs (CLDs) subjected to sequential hyper- and hypo-osmotic treatments. Changes in ABA content were found to precede that of proline, suggesting that ABA could exert regulatory effects on both osmo-induced proline accumulation and its subsequent mobilization during recovery. When exogenously supplied in the light during recovery, ABA caused inhibition of the apparent rate of proline mobilization with an I50 of about 20 μ M . Under dark conditions, the ABA effect was not observed. This is in accordance with the fact that this effect could be suppressed in the light while using photosynthesis inhibitors. The ABA effect was partly restored under dark conditions when the CLDs were supplied with NADPH at high concentration. Under both conditions, ABA exerted its effect when supplied together with cycloheximide, suggesting that it does not rely on protein synthesis. When turgid CLDs, which heavily absorbed exogenously supplied l -proline, were incubated in the light on the reference medium with ABA, proline mobilization was also restricted, provided ABA was supplied during the period of proline uptake. Surprisingly, in CLDs that had recovered their full turgor after application of successive hyper- and hypo-osmotic treatments, application of ABA led to a very high accumulation of proline. In contrast, in freshly cut turgid CLDs incubated in presence of ABA, the basic proline level was only weakly enhanced. Thus, the apparent inhibitory effect of ABA on proline mobilization could be mediated through both an activation of biosynthesis and an inhibition of catabolism of this amino acid via light-dependent processes that remain to be elucidated.