不同类型龙眼种子发育过程中内源激素含量变化

以焦核龙眼品种白核、闽焦64—1、闽焦64—2和大核品种九月鸟为试材,研究了龙眼种子早期发育过程中内源激素含量的变化。结果表明,龙眼种子发育前期大量的GA,被合成与积累,GA3含量随着种子发育逐渐下降。九月乌的IAA含量在花后40d达到最高,且高于3个焦核龙眼品种。九月乌（IAA＋GA3）／ABA比值在花后30—40d基本不变,而3个焦核品种呈现出急剧下降的趋势,花后40—60d九月乌的（IAA4-GA3）／ABA比值先降低后上升,而3个焦核品种均在上升。由此可推测焦核龙眼落果主要受到IAA和ABA的影响,焦核龙眼早期果实发育IAA含量升高将减少焦核果的落果,有利于焦核率的提升。     

Regulation of phytohormones on root primordium initiation and adventitious root formation in the etiolated shoots of Paeonia suffruticosa ‘Yinfen Jinlin’

Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mechnisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstructures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated softwood shoots of Paeonia suffruticosa ‘Yinfen Jinlin’. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages: shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protrusion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043 nmol•g^–1 FW on the bases of shoots, respectively. CTKs which included isopentenyl adenine (iPA), zeatin riboside (ZR) and dihydrozeatin riboside (DHZR) were 0.949, 0.695 and 2.034 nmol•g^–1 FW, respectively. DHZR is active among CTKs. The ratio of IAA to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primordium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. IAA levels in the treated shoots increased gradually to its highest level (three times of control) at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10:1.     

Regulation of phytohormones on root primordium initiation and adventitious root formation in the etiolated shoots of Paeonia suffruticosa''''Yinfen Jinlin''''

Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mech-nisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstructures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated softwood shoots of Paeonia suffruticosa 'Yinfen Jinlin'. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages: shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protrusion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043 nmol·g-1 FW on the bases of shoots, respectively. CTKs which included isopentenyl adenine (iPA), zeatin riboside (ZR) and dihy-drozeatin riboside (DHZR) were 0.949, 0.695 and 2.034 nmol·g-1 FW, respectively. DHZR is active among CTKs. The ratio of IAA to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primordium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. IAA levels in the treated shoots increased gradually to its highest level (three times of control) at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10:1.     

The role of root exudates in specific apple (Malus × domestica Borkh.) replant disease (SARD)

In an effort to improve our understanding of the specific apple replant disease (SARD), direct and indirect effects of phytohormones and related compounds (abscisic acid, 6‐benzyladenine, indole‐3‐acetic acid, 1‐naphthaleneacetic acid, and gibberellins GA₃ or GA₄) on root exudates of apple seedlings were evaluated as a potential mediating factor in the infection process. In the first type of experiments, radioactively labeled hormonal substances were applied to the stumps of decapitated apple‐seedlings and the occurrence of radioactivity in root exudates and their qualitative characterization were examined (direct influence). In another set of experiments, the effects of leaf‐applied plant growth regulators on the amount and composition of the predominant organic acids, carbohydrates, and amino acids/amides were studied. Cherry seedlings resistant to SARD and apple seedlings with dormant apical buds and, thus, not susceptible to infection were used for comparison. The results showed no differences in exudation of applied plant growth regulators between growing cherry and apple seedlings. Thus, a direct effect of plant hormones on the infection process is unlikely. However, leaf treatments with growth regulators, in particular with auxin‐type compounds and abscisic acid, increased exudation of alditols. This may indicate that plant hormones are, to some degree, indirectly involved in the infection process.     

番木瓜不同株性植株初蕾前后叶片的内源激素水平

在番木瓜初蕾前后,以嫩叶为材料,采用高效液相色谱(HPLC)技术,测定番木瓜雌株、两性株及雄株内源激素含量的变化.结果显示:番木瓜3种株性植株叶片的GA3、IAA、ZR、ABA含量在花芽分化、现蕾及开花3个发育阶段均具有明显的变化规律和差异性,且变化临界点为初蕾形成时.内源激素含量比值变化表现为,雄株在初蕾前后ZR/IAA与ZR/ABA比值一直明显高于雌株和两性株的;雌株的IAA/GA3与IAA/ABA比值在初蕾时出现1个明显的高峰值;3种株性植株叶片的GA3/ZR比值则均呈现出初蕾前较低,而初蕾后逐渐上升的趋势.     

马铃薯块茎发育期主要植物激素的动态变化

为了明晰几种主要的植物激素在马铃薯块茎形成中的作用,本研究采用LC-MS/MS法测定了马铃品种‘PB06’及品种‘会-2’块茎发育不同时期叶片、匍匐茎/块茎组织中植物激素ABA、GA3、JA和IAA含量的动态变化。结果显示,随着块茎的发育,匍匐茎/块茎中ABA及JA含量增加;叶片中ABA含量逐渐增加,JA含量先上升后下降,两个品种变化趋势相同。GA3的积累随着匍匐茎的膨大而下降;IAA含量峰值出现在匍匐茎膨大时,并且在之后匍匐茎的膨大中仍然维持高含量水平。表明,IAA及GA3对匍匐茎的伸长是必要的,ABA、JA是诱导块茎形成的正调控因子,GA3为负调控因子。该研究结果对开展植物激素调控块茎形成机理的研究具有重要的支撑作用。     

柱型苹果茎尖培养中嫩茎增殖与植物激素的关系

当培养基含有较低浓度ＢＡ时,柱型苹果‘舞姿’、短枝型‘金矮生’和普通型‘金冠’的嫩茎增殖都基本正常,当ＢＡ浓度较高时,柱型苹果品种嫩茎仍能保持正常状态,而短枝型和普通型品种受到强烈抑制。在较高浓度ＢＡ培养基中,短枝型和普通型品种的内源激素变幅很大,而且继代培养后期恢复很慢,相比之下,柱型品种内源激素变幅小,而且恢复快。初步分析,柱型苹果嫩茎增殖对高浓度ＢＡ具有强的忍耐能力,其原因与所含高水平的ＣＴＫ有密切关系。     

银杏雌雄株内源激素和核酸的变化

测定了银杏朱和雄株实生树内源激素及核酸含量在生长季节的变化。结果表明,在３月上旬芽膨大时芽尖中赤霉素含量已达高峰,随后急剧下降,到９月中下旬降到最低点。６月上旬芽尖中玉米素含量升到最高值,生长素则降到最低点,而脱落酸减少到检测水平以下。     

Effects of Lead,EDTA, and IAA on Nutrient Uptake by Alfalfa Plants

ABSTRACT

The element concentrations of alfalfa plants exposed for 10 d to 40 mg lead (Pb) L^{? 1} from lead nitrate [Pb(NO₃)₂] alone, or combined with ethylenediaminetetraacetic acid (EDTA) and indole-3-acetic acid (IAA), was determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Indole-3-acetic acid at 10 μ M and Pb/EDTA/IAA at 10 μ M increased potassium (K) concentration in roots by 87% and 94%, respectively (P < 0.05). However, IAA at 100 μ M decreased K concentration in leaves (P < 0.05). Plants exposed to 100 μ M IAA, Pb/IAA at 100 μ M, and Pb/EDTA/IAA at 100 μ M had, respectively, 30%, 55%, and 40% more sulfur (S) in leaves than control plants (P < 0.05). Lead and Pb/IAA reduced Ca concentration in stems and leaves (P < 0.05). Conversely, Pb and Pb/EDTA increased Cu concentration in roots and stems. IAA at 100 μ M, Pb, and Pb/EDTA/IAA decreased Zn concentration in roots (P < 0.05). Manganese (Mn) and molybdenum (Mo) concentration in roots and stems was lower in plants treated with Pb and Pb/IAA (P < 0.05). Pb and Pb/IAA reduced (P < 0.05) the iron (Fe) concentration in roots. However, the addition of EDTA and IAA at 10 μ M reduced the negative effects of Pb on Fe absorption.