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611.
肖翊华;徐孟亮;刘文芳 《武汉植物学研究》1992,10(2):128-132
本文报道了农垦58s和农垦58幼穗发育期长短日下吲哚乙酸氧化酶和过氧化物酶的活性变化。结果表明:58s LD叶片中吲哚乙酸氧化酶活性从花粉母细胞形成期至花粉内容物充实期显著低于58s SD,与游离IAA的积累密切相关,可能影响花粉育性;但过氧化物酶的活性在上述时期显著高于58s SD,与游离IAA的积累无关,其作用尚不清楚。58s LD幼穗及花药中两酶活性在减数分裂期和花粉内容物充实期均较58s SD高,与同期幼穗及花药中游离IAA的亏缺有一定联系,从而可能在一定程度上影响花粉育性。对照农垦58叶片和幼穗及花药中两酶活性变化都不呈现上述现象。 相似文献
612.
We have studied the role of endogenous auxin on adventitious rooting in hypocotyls of derooted sunflower (Helianthus annuus L. var. Dahlgren 131) seedlings. Endogenous free and conjugated indole-3-acetic acid (IAA) were measured in three segments of hypocotyls of equal length (apical, middle, basal) by using gas chromatography-mass spectrometry with [13C6]-IAA as an internal standard. At the time original roots were excised (0 h), the free IAA level in the hypocotyls showed an acropetally decreasing gradient, but conjugated IAA level increased acropetally; i.e. free to total IAA ratio was highest in the basal portion of hypocotyls. The basal portion is the region where most of root primordia were found. Some primordia were seen in this region within 24 h after the roots were excised. The quantity of free IAA in the middle portion of the hypocotyl increased up to 15 h after excision and then decreased. In this middle region there were fewer root primordia, and they could not be seen until 72 h. In the apical portion the amount of free IAA steadily increased and no root primordia were seen by 72 h. Surgical removal of various parts of the hypocotyl tissues caused adventitious root formation in the hypocotyl regions where basipetally transported IAA could accumulate. Reduction in the basipetal flow of auxin by N-1-naphthylphthalamic acid and 2,3,5-tri-iodobenzoic acid resulted in fewer adventitious roots. The fewest root primordia were seen if the major sources of endogenous auxin were removed by decapitation of the cotyledons and apical bud. Exogenous auxins promoted rooting and were able to completely overcome the inhibitory effect of 2,3,5-tri-iodobenzoic acid. Exogenous auxins were only partially able to overcome the inhibitory effect of decapitation. We conclude that in sunflower hypocotyls endogenously produced auxin is necessary for adventitious root formation. The higher concentrations of auxin in the basal portion may be partially responsible for that portion of the hypocotyl producing the greatest number of primordia. In addition to auxins, other factors such as wound ethylene and lowered cytokinin levels caused by excision of the original root system cuttings must also be important. 相似文献
613.
Wim M. van der Krieken Hans Breteler Marcel H. M. Visser Wilco Jordi 《Physiologia plantarum》1992,85(4):589-594
Maximum root formation on apple ( Malus ) shoots cultured in vitro occurred after an incubation in the dark on medium containing 3.2 or 10 μ M indolebutyric acid (IBA) plus riboflavin. Omission of riboflavin or culture in light resulted in a significant decrease in the number of roots formed. About 95% of the absorbed IBA was inactivated by conjugation, ca 4% was extracted as the free IBA acid (IBAH) and only 1% as IAAH. It was investigated whether the decrease in root formation caused by exposure to light or omission of riboflavin during culture was parallelled by a shift in the concentrations of the physiologically active auxin compounds (IBAH and IAAH) in the stem base, i.e. the location where the roots emerge. At least 90% of the absorbed 3 H-IBA was located in the stem base. Omission of riboflavin, either in the dark or in the light, had no effect on the IBAH and IAAH concentrations, whereas root formation decreased significantly. Incubation in the light on medium containing 10 μ M IBA with or without riboflavin and culture in the dark on medium containing 3.2μ M IBA plus riboflavin resulted in similar IBAH and IAAH concentrations. However, the number of roots was significantly lower after culture in the light. Therefore, we conclude that the synergistic effect of riboflavin and the antagonistic effect of light on IBA-induced root formation are not solely based on changes in the concentrations of the active auxin components resulting from IBA uptake. 相似文献
614.
615.
Calli of salt tolerant (Bhoora rata) and salt susceptible (GR11) rice varieties were cultured on Linsmaeir and Skoog’s medium containing LD50 concentration of NaCl (200 mM) and hydroxyproline (10 mM). Growth, proline content and activity of proline and IAA oxidases
of the cultured tissues were determined at the end of 0, 2, 4, and 6 weeks of incubation. Hydroxyproline resistant calli of
both rice varieties when cultured on Linsmaeir and Skoog’s medium containing hydroxyproline and NaCl showed increased dry
weight and proline content as compared to NaCl stressed calli. The levels of proline and IAA oxidases were also low in the
hydroxyproline resistant calli. 相似文献
616.
A cold pretreatment is usually applied to induce maize androgenesis. Peroxidase activity, including indole-3-acetic acid (IAA) oxidase activity, and endogenous IAA concentrations were followed during a cold pretreatment (14 days, 7°C) in anthers of two maize genotypes, Seneca 60 and DH5×DH7, respectively with a low or high androgenetic response. The most prominent result was the absence of a detectable IAA oxidase activity in DH5×DH7. Adding effectors of IAA-oxidase activity or IAA transport did not affect significantly the crude peroxidase activity of DH5×DH7 anthers while inducing a clear inhibition of androgenesis at higher concentrations. No strict correlation was found between IAA level and physiological response, the low responding variety having as much IAA as DH5×DH7. However, for DH5×DH7, every treatment that lowered the IAA level after 14 days of cold resulted in a decrease in androgenetic response. 相似文献
617.
Dynamic function and regulation of apoplast in the plant body 总被引:1,自引:0,他引:1
Naoki Sakurai 《Journal of plant research》1998,111(1):133-148
Apoplast is the internal environment of plant. Our body posses the internal environment that consists of blood, lympha, and
tissue fluid. Plant cells are also cultivated and surrounded by a liquid medium in the apoplast. As well as various important
functions of the internal environment in our body, apoplast function is also prerequisite for the plant life. There are so
far seven distinct functions of apoplast. (1) Growth regulation with apoplastic enzymes by altering cell-wall properties through
degradation, synthesis, orientation and cross-linking of supra-molecules of cell walls, such as cellulose, non-cellulosic
polysaccharides, proteins, and lignin; (2) Skeleton sustained by cellulose microfibrils, lignin and various types of structural
proteins with distinctively high content of hydroxyproline, proline or glycine; (3) Skin to defend symplast from desiccation,
pathogens' attack and harmful environmental factors, such as ozone and sulfur dioxide; (4) Transportation route for not only
well-known molecules of water, inorganic ions, and sugar, but also plant hormones, oligosaccharides and proteins; (5) Homeostasis
of the internal environment by controlling ionic balance, pH and water content; (6) Adhesion of cell to cell; (7) Gas exchange
space of leaf for photosynthesis. The present article reviews the recent advances in studies of several aspects of the dynamic
function and regulation of apoplast. 相似文献
618.
红光(R)和远红光(Fr)都抑制水稻胚芽的生长,但对胚芽鞘来说,红光抑制其生长,远红光表现出部分逆转效应。一定浓度单一生长素(IAA)促进水稻胚芽鞘的生长,而赤霉素(GA_3)与生长素作用相反。对于水稻的过氧化氢酶(CAT)、过氧化物酶(POX),红光促进两种酶的活性,远红光则表现出逆转效应。单一10~(-2)ppmIAA、10~(-2)ppmGA_3都促进其活性。照光时,在10~(-2)ppm IAA存在的条件下,红光表现为促进,远红光则表现为抑制;但在10~(-2)ppm GA_3存在的条件下,红光反而对两种酶的活性有抑制作用,远红光则表现为促进作用。 相似文献
619.
We tested that the hypothesis that root elongation might be controlled by altering the level of ethylene in intact primary
roots of maize(Zea mays L.). We measured root elongation in a short period using a computerized root auxanometer. Compounds which regulate ethylene
production were applied to intact primary roots in different time periods. Root elongation was stimulated by the treatment
with ethylene antagonists such as Co2+, aminoethoxyvinylglycine (AVG) and L-canaline. This result suggested that root elongation was closely related to ethylene
level of intact primary roots. Furthermore, IAA- and 1-aminocyclopropane-1-carboxylic acid (ACC)-induced inhibition of root
elongation was reversed by treatment with Co2+. The application of ACC to roots which have been exposed to IAA and Co2+ have no significant effect on root elongation. However, the inhibition of root elongation by ACC in roots previously treated
with IAA and AVG became manifest when the applied IAA concentrations were lower. These results were consistent with the hypothesis
that the level of ethylene in intact roots functions to moderate root elongation, and suggested that auxin-induced inhibition
of root elongation results from auxin induced promotion of ethylene production. 相似文献
620.
芦丁对绿豆幼苗营养生长的影响及其与IAA的相互作用 总被引:5,自引:0,他引:5
观察了植物体内的天然黄酮芦丁和吲哚乙酸(IAA)对绿豆幼苗营养生长的影响并测定胚轴中的芦丁和IAA含量.光照条件下芦丁(60μg/mL以下)处理对绿豆幼苗生长有一定促进作用,表现为胚轴和主根伸长加快、侧根数目增多、鲜重或干重增加;而光照条件下更高浓度芦丁(80μg/mL以上)处理及黑暗条件下芦丁(20~100μg/mL)处理对绿豆幼苗生长有抑制作用.当培养基中的芦丁浓度为60~80 μg/mL时,光照下的幼苗比暗处理的幼苗在胚轴中积累更多的芦丁;而芦丁浓度为40μg/mL以下和接近100μg/mL时幼苗在光照下累积的芦丁较暗处理的幼苗更少.0.1μg/mL以上的IAA促进芦丁的累积而进一步抑制幼苗胚轴和主根的伸长.当培养基中含有40 μg/mL的芦丁和0.5μg/mL的IAA时,胚轴中累积的芦丁达到高峰.芦丁降低黄化幼苗内源性IAA在胚轴中的累积,并抑制幼苗对IAA的吸收. 相似文献