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1.
林生山黧豆幼苗用[3H]-天门冬氨酸标记后,高丝氨酸在6h内迅速增加。高丝氨酸合成速率降低后,2,4-二氨基丁酸的合成量上升,于18h达到高峰。赖氨酸和苏氨酸与二氨基丁酸的合成表现有协同反馈机制。结果支持了天门冬半醛转氨生成二氨基丁酸的假说。盐胁迫、渗透胁迫和热激增加了二氨基丁酸的合成,可能是因为不同胁迫条件都造成了细胞脱水,从而促进了二氨基丁酸的合成。 相似文献
2.
Liming Shen David M. Orcutt Joyce G. Foster 《Environmental and Experimental Botany》1990,30(4):497-504
2,4-Diaminobutyric acid (A2bu) may be responsible for the apparent toxicity of flatpea (Lathyrus sylvestris L.) forage to some livestock. To obtain information relative to environmental regulation of A2bu, 3-month old flatpea plants, cv. “Lathco”, were subjected to water-deficit stress for 1, 2, and 4 weeks. A2bu, the most abundant free amino acid in roots, stems, and leaves, increased nearly 100% in roots of stressed plants. Increases in the concentrations of asparagine (Asn), proline (Pro), and arginine (Arg) occurred in roots; Asn, Pro, and 4-aminobutyric acid (Abu) in stems; and Pro and homoserine (Hse) in leaves also occurred in response to drought stress. Proline was a minor constituent of the free amino acid pool, even under water-deficit stress. The distribution of A2bu and Pro in the stressed plants (roots > stems > leaves) was the reverse of that in plants supplied with adequate water (roots < stems < leaves). As concentrations of Asn and Abu decreased from roots to leaves in control tissues, concentrations of Hse and A2bu increased in roughly the same proportions. This observation suggests that Abu and Asn may be precursors of A2bu and Hse, respectively. The increase in A2bu levels in aerial parts of drought-stressed flatpea plants is probably not sufficient to lower the feed value of the forage. 相似文献
3.
An in vitro synthetic reaction system was established with 2,3-3H-aspartic acid (Asp) as a substrate and the homogenate of fiatpea ( Lathyrus sylvestris L. ) leaves as the crude enzyme extract. The results showed that 3H-Asp was incorporated into 2,4-diaminobutyric acid (DABA). The incorporation was inhibited by the addition of glutamic acid (Glu). 3H-Asp was also incorporated into DABA after the cmde enzyme was dialyzed, indicating that Asp as a substrate for DABA synthesis was catalyzed by a group of enzymes which converted Asp to DABA in flatpea. From the in vitro reactions it was proved that DABA and γ-aminobutyric acid (GABA) could not be mutually substituted as substrates. 相似文献
4.
应用二维电泳技术,分析了经水分胁迫(PEG)、盐分胁迫(NaCl)和热激(40℃)处理后林生山黧豆(LathyrussylvestrisL.)体内蛋白质多肽及其含量的变化。有些蛋白质经PEG、NaCl和热激处理后可以产生相同的变化。两种不同的胁迫因子对某些蛋白质的影响有一定的共同性。特定的胁迫条件可以造成特定的影响。不同胁迫因子对同一蛋白质多肽可以造成不同的影响。胁迫下蛋白质的变化可能与林生山黧豆抵抗和适应胁迫条件的能力以及体内非蛋白质氨基酸的代谢有关 相似文献
5.
A new amino acid previously detected in 17 species of Acacia has been isolated from seeds of Acacia angustissima and identified as oxalylalbizziine. These seeds also contain more than 6% dry weight of 2-amino-4-acetylaminobutyric acid, which has not been reported previously in a legume, and lower concentrations of 2,4-diaminobutyric acid. 相似文献
6.
Use of flatpea (Lathyrus sylvestris L.) as a forage is limited because of nonuniform seed germination and the potentially toxic effects of 2,4-diaminobutyric acid (A2bu), a nonprotein amino acid found in seeds and vegetative tissues. The effects of ethephon (2-chloroethyl phosphonic acid) on seed germination, amino acid leachates of seeds, and amino acid composition (particularly A2bu) of seedlings were investigated. Germination of flatpea seeds, imbibed for 16 h in 0, 100, 200, 400, 800, and 1600 mg/L ethephon, did not differ, but amino acid leachates tended to increase up to 200 mg/L ethephon and then decline at higher concentrations. The major amino acid constituents in leachates were A2bu, 4-aminobutyric acid (Abu), and homoserine (Hse). Dry matter accumulation of seedlings grown from ethephon-treated seeds was reduced for second cuttings grown from ethephon-treated seeds and high nitrogen grown plants. During regrowth, free amino acid accumulation was most pronounced in leaves of plants supplied with high nitrogen. The most abundant free amino acids in flatpea tissues were the same as those in seed leachates, but concentration and relative abundance varied with nitrogen level, plant part, and ethephon treatment. Results suggest that ethephon seed treatments can have persistent effects on the growth and amino acid composition of flatpea seedlings grown under different nitrogen regimes. 相似文献
7.
Assimilation of nitrate and ammonium by the Scots pine (Pinus sylvestris) seedling under conditions of high nitrogen supply 总被引:3,自引:0,他引:3
Seedlings of Scots pine ( Pinus sylvestris L.) were grown on perlite for 21 days under controlled conditions. Apart from the water control, KNO3 (15 m M ), (NH4 )2 SO4 (7.5 m M ), and NH4 NO3 (15 m M ) were offered to study the effects of a high nitrogen supply on nitrogen assimilation. In some experiments 1.3 m M potassium was added to the basic ammonium solutions. In labelling studies nitrate and ammonium were 2.3 atom%15 N-enriched. It was found that over the 21-day period approximately three times more ammonium-N was taken up than nitrate-N. However, nitrate and ammonium, applied simultaneously, were taken up to the same extent as if they were applied separately (additivity). The presence of K+ in the medium did not affect N-uptake. Among the soluble N-containing compounds nitrate, ammonium and 8 amino acids were quantified. It was found that assimilation of nitrate can cope with the uptake of NO− 3 under all circumstances. Neither free nitrate nor ammonium or amino acids accumulated to an extent exceeding the values of water-grown seedlings. On the other hand, in case of high ammonium supply considerably more nitrogen was taken up than could be incorporated into nonsoluble N-containing substance ('protein'). The remaining nitrogen was found to accumulate in intermediary storage pools (free NH4 + , glutamine, asparagine, arginine). Part of this accumulated N could be incorporated into protein when potassium was offered in the nutrient solution. It is concluded that potassium is a requirement for a high rate of protein synthesis not only in crop plants but also in conifers. 相似文献
8.
Tomato plants were cultivated (from 2 to 23 days after germination) in media with NO
3
−
, NH
4
+
, or a mixture of both forms in different proportions used as the N source given with or without 5 mol dm−3 HCO
3
−
. The accumulation of soluble sugars (reducing sugars and sucrose) and free amino acids was higher in the roots and leaves
of NH
4
+
-fed plants than in NO
3
−
-fed plants. Starch accumulation in NH
4
+
-fed plants was higher in leaves (about 28%) and lower in roots (about 37%) in comparison with that of NO
3
−
-fed plants. Plants cultivated in media containing a mixture of NO
3
−
/NH
4
+
were characterized by a lower content of sugars and amino acids accumulation in comparison with that in plants fed with NO
3
−
or NH
4
+
. An elevated HCO
3
−
concentration in the rhizosphere stimulated the accumulation of soluble sugars and free amino acids in all the experimental
variants. There were only small differences in the starch content. 相似文献
9.
Eu3+对山黧豆中的氨基酸及蛋白质代谢作用的研究 总被引:3,自引:1,他引:2
对山黧豆(Lathyrus sativus L.)幼苗整株,喷施一定浓度的Eu3+溶液吸收后,对其相关的生理指标进行测试,结果表明与水喷比较,根中丝氨酸、甘氨酸、丙氨酸、蛋氨酸、亮氨酸、脯氨酸、胱氨酸与对照持平,缬氨酸、酪氨酸、苯丙氨酸、组氨酸略有升高外,其余均低于对照;茎中除精氨酸、脯氨酸、色氨酸略高于对照外,其余均低于对照;叶中除蛋氨酸、色氨酸略高于对照外,其余均低于对照.游离氨基酸总量增加时,茎>根>叶,减少时,根<茎<叶.蛋白质含量经Eu3+ 处理茎中减少,根和叶中增加;水解酶比活性根>茎>叶;Na+、K+-ATPase活力却表现根>茎>叶的趋势.表明Eu3+ 对山黧豆生理活性代谢起到一定的调节作用. 相似文献
10.
Field and laboratory experiments on net uptake of nitrate and ammonium by the roots of spruce (Picea abies) and beech (Fagus sylvatica) trees 总被引:4,自引:0,他引:4
ARTHUR GESSLER STEPHAN SCHNEIDER DOMINIK VON SENGBUSCH PAUL WEBER ULRIKE HANEMANN CHRISTIAN HUBER REAS ROTHE KARL KREUTZER & HEINZ RENNENBERG 《The New phytologist》1998,138(2):275-285
11.
The effect of potentially toxic concentrations of ammonium on root development of Scots pine seedlings raised on Perlite was investigated during growth periods of 3 or 10 weeks after sowing. It was shown that imbalanced ammonium nutrition led to conspicuous changes of root morphology provided the pH value in the medium was allowed to decrease to 3.9 due to the NH+4-dependent proton excretion into the rhizosphere. Ammonium toxicity could not be observed with seedlings treated either with ammonium nitrate or with ammonium chloride at pH 5.3 ? 6.8. While the supply of NH+4 considerably inhibited root development the biomass production of the shoot was increased. Determination of the endogenous level of ammonium in roots and the leaf whorl exclude a simple causal correlation between ammonium toxicity and accumulated ammonium as has been postulated for herbaceous plants. 相似文献
12.
S. E. Wright 《Plant and Soil》1985,88(3):455-459
Summary Flatpea (Lathyrus sylvestris L.) requires seed scarification for rapid germination and specificRhizobium leguminosarum strain for nodulation. Methods of inoculation were investigated to determine which would be effective for at least two weeks after seeding. Application of powdered peat to wet seeds was inadequate. Lime pelleting and granular soil implants were effective inoculants, but there appears to be a different advantage to seedling for earch metod. Granular soil implant caused nodulation to a greater depth on the tap root, and lime pelleting caused plants to exhibit higher acetylene reduction activity. 相似文献
13.
M. Geiger V. Haake F. Ludewig U. Sonnewald & M. Stitt 《Plant, cell & environment》1999,22(10):1177-1199
14.
Effects of acid irrigation and liming on nitrate reduction and nitrate content of Picea abies (L.) Karst. and Oxalis acetosella L. 总被引:2,自引:0,他引:2
Nitrate reductase activities (NRA) and nitrate concentration per unit biomass in Picea abies (L.) Karst. roots from four different soil horizons and in leaves and roots of the frequent field-layer species Oxalis acetosella L. were measured on six different irrigation and liming treatments within the Höglwald project, S-Bavaria, Germany. Liming increased and acid irrigation reduced soil nitrate availability when compared to control plots. Nitrate assimilation capacities of the respective plant compartments per unit of soil volume or ground area were calculated from the NRA per unit of biomass and from the biomass distribution on the various treatments.Mean NRA per unit of biomass in Picea abies roots ranged between 0.23 and 0.09 mol NO
2
-
g-1 d.w. h-1 without significant effects of soil horizon or treatment. Limed and non-limed treatments showed for Picea different root distributions within the soil profile, but root biomass per unit of ground area (295 to 220 g d.w. m-2) was not affected by the various treatments. Thus, nitrate assimilation capacity of Picea roots per unit of ground area ranged between 19.5 and 11.4 mol NO
2
-
m-2 h-1 without major treatment effects.In laminae of Oxalis acetosella mean NRA per unit of biomass ranged between 2.91 and 0.27 mol NO
2
-
g-1 d.w. h-1 and, in contrast to Picea abies, treatment effects were found with NRA on limed plots increased and on acid irrigated plots reduced when compared to control plots. Mean leaf biomass of Oxalis per unit of ground area ranged between 9.57 and 0.66 g d.w. m-2 and responded in a similar manner to the various treatments. Thus, for the Oxalis leaf NRA per unit of ground area (27.85 to 0.18 mol NO2 m-2 h-1) a cumulative response to the variations in nitrate availability was found.The different responses of Picea abies and Oxalis acetosella to changes in soil nitrate availability are discussed with respect to their suitability to prevent soil nitrate leaching. 相似文献
15.
Water culture, growth chamber, greenhouse and field experiments were conducted to compare the effect of NH4−N and NO3−N on yield and N uptake of rapeseed (Brassica campestris L.). In water culture, the yields of 28-day old rapeseed plants grown at 14 μg N ml−1 were double with NO3 compared to NH4, but N uptake was little affected. There was no such effect when concentration was reduced to 3.5 or 7 μg N ml−1. The yield and N uptake of 26-day old rapeseed grown on six soils (pH 4.6 to 6.5) in pots in a growth chamber were much greater
with NO3 than with NH4, although N concentration was more in the NH4- than the NO3-grown plants. In a greenhouse experiment with rapeseed grown on 12 potted soils, the N uptake of applied N was greater with
NO3 than with NH4 on all soils. Averages were 63% with NH4 and 78% with NO3. However, NH4-fixation capacities of the soils were only weakly correlated with yield from the two sources of N (r=0.48) and the relation
was similar with N uptake. In contrast to the behavior of water culture, growth chamber and greenhouse experiments, the 33
field experiments did not show consistent difference in seed yield with NH4 and NO3 applied at time of seeding. In nine field experiments where band application was used for Ca(NO3)2, (NH4)2 SO4, NH4 NO3, yield tended to be greatest for (NH4)2SO4. However, in 19 experiments on acid soils with and without lime, yields in most cases were similar with (NH4)2SO4 and NH4 NO3. Nitrification inhibitors were added to spring banded NH4-based fertilizers in five experiments, but the yields were not influenced.
Scientific Paper No. 558, Lacombe Research Station, Agriculture Canada. 相似文献
16.
Five nitrate:ammonium ratios at two N-levels were tested with and without nitrapyrin [2 chloro-6-(trichloromethyl) pyridine]
for grain production on a sandy soil. Treatments were applied to field maize as nutrient solutions, in one application, six
weeks after planting. Nytrapyrin resulted in an increase in grain yield at a nitrate:ammonium ratio of 1:3 but in a decrease
at a 0:1 ratio. The optimum nitrate:ammonium ratio was close to 1:3 with nitrapyrin and close to 3:1 without nitrapyrin. Nitrapyrin
had an effect on NH4
+-N in the topsoil and NO3
−-N in the subsoil at 70 days after application. Interactions of nitrate:ammonium ratios and N-levels were shown for leaf N
concentration, soil mineral N and soil pH. 相似文献
17.
Appearance of nitrate reductase (NR, EC 1.6.6.1–3), nitrite reductase (NiR, EC 1.7.7.1) and glutamine synthetase (GS, EC 6.3.1.2) under the control of nitrate, ammonium and light was studied in roots, hypocotyls and needles (cotyledonary whorl) of the Scots pine ( Pinus sylvestris L.) seedling. It was found that appearance of NiR was mainly controlled by nitrate whereas appearance of GS was strongly controlled by light. In principle, the NR activity level showed the same dependency on nitrate and light as that of NiR. In the root, both nitrate and ammonium had a stimulatory effect on GS activity whereas in the whorl the induction was minor. The level of NiR (NR) activity is high in the root and hypocotyl and low in the cotyledonary whorl, whereas the GS activity level per organ increases strongly from the root to the whorl. Thus, in any particular organ the operation of the glutamine synthetase/glutamate synthase (GS/GOGAT) cycle is not closely connected to the operation of the nitrate reduction pathway. The strong control of GS/GOGAT by light and the minor sensitivity to induction by nitrate or ammonium indicate a major role of the GS/GOGAT cycle in reassimilation of endogeniously generated ammonium. 相似文献
18.
R. J. BOX 《Plant, cell & environment》1987,10(2):169-176
Abstract The uptake of ammonium and nitrate nitrogen by cultured plants of the green freshwater alga Chara hispida L. has been compared quantitatively with the contribution of its rhizoidal tissue. In the short-term, the rhizoid takes up 7–20% of the ammonium nitrogen, and about 15% of the nitrate that is taken up by whole plants under similar conditions. The uptake was studied over a range of both temperatures and external concentrations. The apparent activation energy for the uptake of NH4+ and NO3? by the whole plant was found to be 50 kJ mol?1 and 30 kJ mol?1, respectively. For the rhizoid, the values were similar for both nitrogenous ions, 106 kJ mol?1 and 70–100 kJ mol?1. The rhizoidal uptake mechanism for ammonium nitrogen operates more efficiently compared to that in the whole plant. Nitrate is taken up by the rhizoid by a mechanism with a substrate affinity higher than in the plant taken as a whole. The possible ecological significance of the results is discussed. 相似文献
19.
扫帚菜、蕨菜营养成分分析 总被引:8,自引:0,他引:8
姚玉霞 《氨基酸和生物资源》2003,25(1):1-2
对扫帚菜、蕨菜两种山野菜的粗蛋白、粗脂肪、膳食纤维、胡萝卜素、氨基酸、维生素及微量元素等营养成分进行了分析.结果表明,两种山野菜营养丰富,各种营养成分较为齐全,为开发食用山野菜等绿色食品提供科学依据和参考. 相似文献
20.
M. Klemš M. Truksa I. Macháccaron;ková J. Eder S. Procházka 《Plant Growth Regulation》1998,26(3):195-202
The uptake, distribution and metabolism of 2,4-D using 14C-labelled 2,4-dichlorophenoxyacetic acid (14C-2,4-D) was studied in isolated hypocotyl and cotyledon explants of cucumber (Cucumis sativus L.) in vitro. Cotyledons had a higher uptake capacity than hypocotyls; the uptake in cotyledons increased linearly up to 20 h, while in hypocotyls only up to 8 h. The distribution of 14C-activity in both organs was basipetal, but more pronounced in cotyledons. The 2,4-D taken up by cotyledons was metabolized very rapidly: only 7% of 14C-activity was associated with free 2,4-D after 20 h exposure. Hypocotyls metabolized 2,4-D more slowly: after 20 h 50% of the 14C-activity was still associated with free 2,4-D. After short incubation periods (2–5 h) 2,4-D-aspartate was a predominant metabolite, after longer incubation (8–20 h) 2,4-D-glucosyl ester prevailed. Roots or callus were formed on the base of cotyledons depending on the length of exposure to 2,4-D. 相似文献