Phase Change in Hedera helix L: I. GIBBERELLIN-LIKE SUBSTANCES IN THE TWO GROWTH PHASES

Gibberellin-like substances were extracted from all parts ofthe juvenile and adult growth phases of Hedera helix. A numberof extraction techniques were employed and estimatos of theamount of gibberellin-like activity present were made usingthree bioassays. Gibberellin like substances were present inapproximately equal amounts in leaves at the two growth phasesand appeared to be localized, in the main, in chloroplasts.Apical ‘buds’ of the juvenile phase were shown tocontain higher levels of gibberellin-like substances than theiradult counterparts. Roots, which under normal circumstancesare associated only with the juvenile phase, contained highlevels of extractable gibberellin-like substances.     

ABSCISIC ACID EFFECTS ON FRONDS AND ROOTS OF LEMNA MINOR L.

Plants of Lemna minor L. were grown in axenic culture in order to investigate the direct effect of abscisic acid (ABA) on individual fronds and roots. Both frond and root growth rates were inhibited by 60%, and total growth of both organs was reduced by 30% with ABA concentrations of 2 mg/l. Abscisic acid inhibited frond reproduction, and treated fronds tended to remain attached to parents. Reduction of root elongation and frond expansion occurred within 1–4 hr. Prolonged exposure to ABA inhibited both cell enlargement and cell division in the roots. The results are discussed in the light of current views on the control of growth with endogenous levels of promoter and inhibitor hormones.     

Phase Change in Hedera helix L: II. THE POSSIBLE BOLE OF ROOTS AS A SOURCE OF SHOOT GIBBERELLIN-LIKE SUBSTANCES

When synthesis was estimated by the agar diffusion techniqueboth basal and lateral adventitious roots of Hedera helix L.in the juvenile growth phase were shown to synthesize gibberellin-likesubstances. Seedlings and cuttings from juvenile ivy could begrown in water culture for several weeks. When roots were excisedfrom these plants shoot growth was reduced in comparison withthat of intact plants. The stems, apices, and leaves of derootedseedlings and cuttings contained lower levels of extractablegibberellin-like substances than comparable organs of intactplants. The major zone of gibberellin-like activity in intactplants co-chromatographed with gibberellins A₁ and A₃. Whenthese gibberellins were applied to plants grown in culture theywere found to promote growth of intact but not derooted plants.These findings are discussed in relation to the role of rootfactors and particularly gibberellins in phase change.     

黄颡鱼重组生长激素的制备及对其鱼苗生长的影响

生长激素在渔业生产中具有重要的应用价值, 通过制备黄颡鱼(Pelteobagrus fulvidraco)同源重组生长激素并用于促生长实验, 从而为建立鱼苗快速培育方法提供理论依据。根据已知黄颡鱼生长激素(PfGH)基因cDNA序列, 利用IPTG诱导和SDS-PAGE分析方法, Western印迹表明在IPTG终浓度1.0 mmol/L、温度17℃和培养时间14h的条件下, 黄颡鱼生长激素基因在大肠杆菌中大量表达, 获得重组生长激素蛋白。然后, 随机选取黄颡鱼分为4组放入室内水族箱中进行养殖, 每箱35尾, 体质量为(0.850.01) g, 每组设3个平行, 水体循环净化。用制备的重组生长激素浓度分别为0、1、5和10 mg/L对黄颡鱼进行浸泡处理, 每周一次, 0为对照组。在养殖4周后, 对各组增重率和特定生长率进行比较, 结果表明1 mg/L组增重率和特定生长率分别比对照组提高了29.67% (P0.05)和11.90% (P0.05), 5 mg/L组增重率和特定生长率分别比对照组提高了21.32% (P0.05)和8.83% (P0.05), 各组间体成分等均无明显差异。停用生长激素4周后, 各组黄颡鱼的生长性能、体成分等均无显著差异。研究表明通过原核表达可以获得黄颡鱼重组生长激素, 用于促进鱼苗生长培育的最佳浸泡浓度为1 mg/L。       

硼和赤霉酸对芦苇纤维生长的影响

1.芦苇在缺硼时,茎中的纤维细胞短,当供给硼酸(浓度1—200μmol/l)后,纤维细胞增长,但以100μmol/l 浓度最为适宜。单独使用赤霉酸也有增长效果。硼酸(200μmol/l)和赤霉酸(50μmol/l)混合施用时效果最佳,纤维细胞的长度增加最多,长宽比也增大,同时植株增高。2.显微观察表明,硼酸和赤霉酸混合处理还能增加纤维细胞的数目和纤维细胞层的厚度。3.在硼酸和赤霉酸混合处理下,H~3-葡萄糖大量渗入到纤维细胞壁中。4.实验说明,硼酸和赤霉酸都对纤维细胞的生长发育有影响。两者混合施用还有协同效应。     

绿原酸对草鱼鱼种生长、非特异性免疫和肉质的影响

为考察绿原酸对草鱼鱼种生长、非特异性免疫指标和肌肉品质的影响,在基础饲料中分别添加0.00%（对照组）、0.01%、0.02%、0.04%、0.06%、0.08%绿原酸,饲养平均体重（3.190.03） g的草鱼鱼种。经60d饲养,各组草鱼增重率分别为283.1%、305.7%、307.3%、329.6%、308.3%、303.0%,饲料系数分别为1.45、1.33、1.33、1.26、1.30、1.36;与对照组相比,添加0.04%绿原酸显著提高草鱼鱼种增重率,降低了饲料系数（P0.05）,添加0.01%、0.02%、0.06%绿原酸有提高草鱼鱼种增重率的趋势;在饲料中添加0.04%绿原酸可显著提高肝胰脏SOD活性（P0.05）,添加0.08%绿原酸可显著降低血浆天门冬氨酸氨基转移酶活性（P0.05）,各组肝胰脏溶菌酶、血浆碱性磷酸酶和丙氨酸氨基转移酶活性无显著差异（P0.05）。对肌肉成分的分析表明,各组水分、粗脂肪含量无显著差异（P0.05）,但添加0.04%绿原酸可显著提高肌肉粗蛋白、缬氨酸、异亮氨酸、组氨酸、必需氨基酸和总氨基酸含量（P0.05）。添加0.02%绿原酸可显著提高肌肉羟脯氨酸、胶原蛋白含量（P0.05）。综上所述,适量绿原酸能改善草鱼鱼种生长性能、非特异性免疫功能和肌肉品质。草鱼鱼种饲料中绿原酸添加量推荐为0.04%。       

THE EFFECTS OF GIBBERELLIC ACID AND KINETIN ON THE GROWTH OF MAJESTIC POTATO

The effects of spraying potato plants (var. Majestic) with gibberellic acid and kinetin were investigated. Gibberellic acid increased both leaf area and dry-matter production over the short period of the experiment, but there were indications that this would not persist at maturity. Kinetin alone depressed leaf area and dry-matter production, but this did not occur in the presence of gibberellic acid. The mean net assimilation rate measured over a 2-week period was not significantly reduced by gibberellic acid.     

INTERACTIVE EFFECTS OF GIBBERELLIC ACID AND SALINITY ON THE GROWTH OF BEANS

Nieman , R. H., and Leon Bernstein . (U. S. Salinity Laboratory, Riverside, Calif.) Interactive effects of gibberellic acid and salinity on the growth of beans. Amer. Jour. Bot. 46(9): 667–670. 1959.—Dwarf red kidney bean plants, grown from the primary leaf stage to maturity on a graded salt series (0, 1.5, 3.0 and 4.5 atm. O.P. NaCl added to a base nutrient solution), showed a progressive and highly significant growth depression with increasing concentration of NaCl. At low levels of salinity (0 and 1.5 atm. O.P.), gibberellic acid applied as a spray to primary leaves, in concentrations of 10 and 100 p.p.m. in distilled water, increased the stem length, fresh and dry wt. of both the top and the root, the yield of green beans, area per leaf, and the total leaf area per plant. At high levels of salinity (3.0 and 4.5 atm. O.P.) growth was so severely suppressed that the expression of all gibberellin effects, except the increase in stem length, was essentially prevented. Gibberellin was, therefore, ineffective in overcoming the salt-induced suppression of growth. An increased rate of water use per unit leaf area was quite consistently observed with the gibberellin-treated plants. This may be simply the result of the increased exposure to light and to air movement of leaves on an elongated stem.     

饲料中添加叶酸和VB12对中华绒螯蟹幼蟹生长、非特异性免疫和抗病力的影响

为研究叶酸和VB12协同作用对中华绒螯蟹(Eriocheir sinensis)幼蟹生长、非特异性免疫和抗病力的影响,选取初始体重为(2.570.03) g的幼蟹600只,随机分成4组,每组5个重复,每个重复30只幼蟹,分别投喂对照组(不添加叶酸和VB12),单一VB12组(0.2 mg/kg),单一叶酸组(2.3 mg/kg)和联合处理组(0.2 mg/kg VB12 +2.3 mg/kg叶酸)的饲料8周。在养殖实验结束后,先统计成活率和称重,然后从每个处理组随机选取30只幼蟹,用2108 CFU/mL的嗜水气单胞菌注射攻毒2周。实验结果表明:幼蟹的增重率、特定生长率、饲料效率和存活率在联合处理组最高,显著高于对照组(P0.05),但与单一叶酸或VB12组相比不存在显著差异(P0.05)。联合处理组的血清酚氧化酶活性显著高于对照组(P0.05),但与单一叶酸或VB12组也无显著性差异(P0.05)。同时,联合处理组的血清酸性磷酸酶、碱性磷酸酶、溶菌酶活性和血细胞总数等指标最高,其次是单一叶酸组和VB12组,而对照组最低。投喂联合处理组饲料幼蟹的肝胰腺超氧化物歧化酶活性最高,而丙二醛含量和累积死亡率最低。以上结果表明,叶酸和VB12对幼蟹的生长、生理代谢和免疫性能均可能有互补和协同作用,养殖生产中建议饲料中叶酸和VB12添加量分别为2.3 mg/kg和0.2 mg/kg。       

丙酸积累对薛氏丙酸杆菌生长及产酸的影响*

报道丙酸积累对维生素B12产生菌Propionibacterium shermanii生长及丙酸产生的影响,在初糖浓度6％,pH6.5的批次发酵条件下,测定了该菌的耗糖、产酸和茵体生长曲线。发酵24h后,培养基中添加1％、3％和6％的丙酸,发酵结束时菌体干重只有对照的75．2％、65．4％和52.9％,产酸是对照的79.3％、69．2％和39．3％。加入6％的丙酸不能完全抑制耗糖和产酸。部分解除丙酸抑制可使菌体干重增加60％。     

Hormonal Regulation of Morphogenesis and Cold-resistance: II. EFFECT OF COLD-ACCLIMATION AND OF EXOGENOUS ABSCISIC ACID ON GIBBERELLIC ACID AND ABSCISIC ACID ACTIVITIES IN ALFALFA (Medicago sativa L. SEEDLINGS

The endogenous levels of gibberellin and abscisic acid weredetermined in extracts from seedlings of alfalfa (Medicago sativaL.) ov. Hairy Peruvian and cv. Ranger, growing under long daysand high temperatures (not inducing cold-hardiness), or shortdays and low temperatures (inducing cold-hardiness). Under inductiveconditions only Ranger was coldacclimated, exhibiting a rosettegrowth; non-acclimated seedlings of Ranger and Hairy Peruviandeveloped an elongated shoot. Under non-inductive conditionsgibberellin A₃ (GA₃)-like activity was found in both cultivars.Under inductive conditions GA3-like activity increased in HairyPeruvian and was almost non-existent in Ranger. In spite ofmorphological modification, ABA-like activity was hardly affectedby thermophotoperiod conditions. Addition of ABA to the nutrientsolution of seedlings growing under non-inductive conditionssimulated the effects of short days and of low temperatures.It diminished GA3 content, and affected morphological modificationof the seedlings. It is concluded that the modification of theABA/GA balance, through the decrease of the GA level, monitorsthe capacity of the twoalfalfa cultivars to become cold-acclimatedwhen exposed to low temperatures.     

ABA对枸杞体细胞胚发生的调节作用

当枸杞的愈伤组织转入分化培养基后的第一天,内源ABA含量就大幅度增高,并成为胚性细胞分化和发育过程中的第一个峰值,也是最高峰值。这时也正是胚性细胞的启动分化期,从愈伤组织的切片明显可见胚性细胞的形成,同时SDS-PAGE结果也表明有相应的35KD蛋白质组分产生,而在未分化的愈伤组织中则未见该蛋白质组分。分化培养后的第15天,内源ABA含量达到第二个峰值,这时是球形胚形成时期,而35KD蛋白质组分含量也在此时达到最大值。外源ABA不仅可诱导内源ABA起始含量的升高,其含量峰值位于分化后的第一天和第15天,同时外源ABA可明显地提高体细胞胚发生的频率和质量。由此表明ABA含量的升高与胚性细胞的启动和发育密切相关,同时内源ABA与外源ABA对体细胞胚的发生有相同的促进作用。其作用机理可能是由于ABA直接或间接激活相关基因表达形成特异性胚性蛋白质组分,从而为胚性细胞的发生与发育奠定了分子基础。