Effects of NH4:NO3:urea ratio on cut roses yield, leaf nutrients content and proton efflux by roots in closed hydroponic system

The effects of the NH₄:NO₃ ratio in replenishment solution on Rosa L. flower yield and the impact of NH₄ substitution by urea on plant performance and on solution EC and pH have not been studied previously in closed (no leaching) hydroponic systems. A greenhouse experiment with six NH₄:NO₃:urea ratios (0:100:0, 12:88:0, 25:75:0, 50:50:0, 100:0:0 and 0:50:50) and two harvest cycles (winter and spring) was carried out to investigate these relationships. In winter, total and >40 cm cut flower yields were maximal in treatment 25:75:0. At lower NH₄ percentages (12.5:87.5:0 and 0:100:0), growth container solution pH varied between 7.8 and 8.5, reducing P, Ca and Mn concentration in leaves and increasing dry matter allocated to them. At higher NH₄ percentages, Ca uptake was inhibited, solution pH reached 3, and %P in leaves increased. Consequently, reducing sugars concentration in leaves increased and sucrose and starch concentrations decreased. A stepwise regression analysis indicated that the optimal NH₄:NO₃ ratio in feed solution is 40:60, with resulting solution pH of 5.9 in the growth container. In spring the maximum yield was obtained in treatment 0:50:50 and it exceeded the winter yield despite a higher solution EC (4.3 dS m⁻¹ vs. 3.5 dS m⁻¹ at harvest). The beneficial effect of urea (0:50:50 vs. 50:50:0) stemmed from the relatively lower NH₄ concentration in solution, that alleviated the NH₄–Ca uptake competition, and higher pH. The slope of the straight line relating [H⁺ efflux rate] to [NH₄⁺ uptake rate] in treatments 25:75:0, 50:50:0 and 100:0:0 was 0.44 mol H⁺/mol NH₄. In all other treatments the proton efflux was negligible.     

遮阴对丰香草莓光合作用及叶绿素荧光特性的影响

以盆栽丰香草莓为材料,研究了遮阴处理对草莓光合作用及叶绿素荧光特性的影响。结果表明,遮阴处理增加草莓叶柄长度、叶面积以及光合色素含量,但降低了比叶重;遮阴处理显著降低草莓叶片的羧化效率(CE)、暗呼吸(Rd)、光补偿点(LCP)和光饱和点(LSP),提高了其表观量子效率(AQY)和CO2补偿点(CCP)。遮阴后草莓Pn日变化由“双峰”型变为“单峰”型,日光合总量显著低于对照,早晚时分水分利用率(WUE)有所下降。遮阴后,叶片气孔导度(Gs)提高,蒸腾速率(Tr)下降,可能与叶面温度下降有关。叶绿素荧光动力学测定显示,遮阴处理草莓叶片的初始荧光(Fo)和PSⅡ最大光化学效率(Fv/Fm)日变化曲线与对照相似,但Fo值始终低于对照,Fv/Fm值显著高于对照。以上参数表明丰香草莓对弱光环境有一定的适应能力,遮阴处理可以减轻强光下的草莓叶片光抑制程度,提高植株对光能的利用能力,但同时也需要注意提高环境中CO2浓度。     

秋季叶面喷施IAA、6-BA或GA_3对草莓植株的影响

为了探讨植物生长调节剂对秋季草莓苗植株质量的调控,以法国3号草莓(Fragaria×ananassa Duch cv.French3)为材料,研究秋季叶面喷施50mg/L IAA、50mg/L6-BA或25mg/L GA3对草莓苗叶片光合作用、活性氧代谢和植株质量的影响。结果表明,晚秋叶面喷施这3种植物生长调节剂显著提高了叶片的净光合速率和叶绿素a、b含量,提高了SOD和CAT酶活性,同时降低了MDA和活性氧含量。另外,这3种植物生长调节剂处理显著增加草莓茎和根系的干重,使根冠比增加,IAA和6-BA处理还显著提高平均单株花量。因此,秋季叶面喷施50mg/LIAA和50mg/L6-BA可提高草莓苗植株质量。     

Effects of different mulches and irrigation methods on root growth,nutrient uptake,water-use efficiency and yield of strawberry

Field studies were conducted for two consecutive years under sub-temperate climatic conditions at Nauni in district Solan of Himachal Pradesh (30°52′N, 77°11′E 1175 asl) on loamy sand Inceptisols to investigate the effect of different mulches (hay: HM, black polyethylene: BP) on root growth, nutrient uptake, water-use efficiency (WUE) and yield of strawberry cv. Chandler under drip (DI) and surface irrigation (SI) systems. Unmulch (UM) and rainfed treatments were kept as control. Higher soil moisture content was registered under both the mulch materials during entire crop growth period. However, it was greater under BP mulch as compare to HM. The moisture conservation increased by 2.80–12.80% under BP mulch as compared to UM. HM treatment, irrespective of irrigation method increased the minimum soil temperature (2.8–5.2 °C) and reduced the maximum soil temperature (2.7–5.8 °C) as compared to UM. BP mulch increased the minimum soil temperature from 0.4 to 2.5 °C. Application of irrigation moderated the soil (minimum 2.6 and maximum 1.4 °C) temperature. Both the mulch materials were effective in enhancing root growth, nutrient uptake, WUE and yield. Application of mulch enhanced the root growth (63%), nutrient uptake (179.20%), WUE (84.40%) and yield (343%) under DI. However, respective increase under SI was 23.60, 83.80, 109.40 and 219.20%. Under DI, 51% of irrigation water was saved and about 19% higher fruit yield was obtained as compared with SI treatment. Linear regression model could significantly describe the variations in nutrient uptake (N, P and K) and WUE of strawberry under sub-temperate climatic conditions, root mass density was better indicator for estimating nutrient uptake of strawberry.     

氮素水平与光强互作对‘蓝伞’玉簪生长和光合特性的影响

 以蓝灰类型玉簪‘蓝伞’（Hosta 'Blue Umbrella'）为材料，研究了4种光强（自然光照的100%、50%、30%、10%）和4种氮素水平（盆栽土施尿素量0、0.5、1.5和2.5 g·kg^-1）处理对玉簪生长和光合特性的影响。结果表明：‘蓝伞’玉簪的生长和光合特性受光强、氮素水平以及光氮互作的影响。在同一氮素水平下，随着光照强度的减弱，玉簪的生物量、叶面积、叶片数、光合速率及可溶性蛋白含量均表现先上升后下降的趋势，在30%～50%光强下达到最大值；叶绿素含量则随光强的减弱而增加。在同一光照强度下，随着氮素水平的升高，玉簪的生物量、叶面积、叶片数、光合速率及叶绿素和可溶性蛋白含量均呈先上升后下降的趋势，在0.5 g·kg^-1氮素水平下达到最大值。     

Responses of cucumber plant to NH4 and NO3 nutrition: The relative addition rate technique vs. cultivation at constant nitrogen concentration

Different N sources (NO₃⁻, NH₄⁺, or NH₄NO₃) at different relative addition rates (RAR) were supplied to cucumber (Cucumis sativus L.), a species sensitive to NH₄⁺ toxicity. For comparison, cucumber plants were also grown at constant concentrations of 1 and 5 mM NH₄⁺ or 5 mM NO₃⁻. The fresh weight of NH₄⁺-fed plants at RAR 0.15 and RAR 0.25 day⁻¹ was similar to that of NO₃⁻-fed plants, while at RAR 0.35 or RAR 0.45 day⁻¹ growth reduction occurred. When available as a constant concentration, NH₄⁺ decreased plant growth at 5 mM. It is concluded that at low rates of N supply the relative addition rate technique can be used for growing cucumber plants with NH₄⁺ as sole N source without deleterious effects.     

NH4NO3及碳源对红掌愈伤组织诱导影响的研究

以红掌的根段和叶片为外植体,探讨了不同NH3 NO4浓度和不同碳源组合对外植体愈伤组织诱导率的影响.结果表明:红掌再生对NH4 NO3的浓度非常敏感,低浓度的NH4 NO3有利于诱导愈伤组织,浓度较高时抑制愈伤的诱导;而不同的碳源也会影响到外植体愈伤组织的诱导,蔗糖与葡萄糖相比更适合于红掌愈伤组织的诱导.其中NH4 NO3 0 mg/L、蔗糖3％组合中根和叶片的愈伤组织诱导率最高,分别是92.6％和81.5％.     

Effect of CO2 enrichment on photosynthesis,growth and yield of tomato

Net photosynthesis of tomato plants was measured as CO₂ uptake in various light intensities, CO₂ concentrations, O₂ concentrations and temperatures during short-term experiments. Net photosynthesis increased significantly with increasing CO₂ concentration at all light intensities, even at the lowest one. The optimal temperature for photosynthesis increased with CO₂ enrichment. The changes in photosynthesis when the $\text{CO}{}_2\text{O}{}_2$ ratio was varied suggest that the effect of CO₂ enrichment is a result of a reduction in photorespiration.To determine whether the increase in photosynthesis caused by CO₂ enrichment would produce a greater yield, tomato plants were cultivated from seed to harvest in a tightly-closed greenhouse that was enriched with CO₂ continuously during the entire growing-period. The control greenhouse was ventilated by openings in the roof and door. The temperature of the 2 greenhouses was kept the same. Plants enriched with CO₂ showed a significant increase in fresh and dry weight and yield of tomatoes. The results are discussed in relation to earlier work in which CO₂ enrichment was discontinued when there was a need for ventilation.     

Effects of cultural cycles and nutrient solutions on plant growth,yield and fruit quality of alpine strawberry (Fragaria vesca L.) grown in hydroponics

Alpine strawberry (Fragaria vesca L.) was grown in hydroponics with the nutrient film technique, in order to evaluate the effects of four buffer concentrations (1.3, 1.6, 1.9, 2.2 mS cm⁻¹) and two cultural cycles (summer-spring versus autumn-spring) in terms of growth, yield and fruit quality (dry and optical residues, sugars, acids, antioxidants, mineral composition). The longer summer-spring cycle gave a correspondingly higher yield than the autumn-spring one. The 1.3 mS cm⁻¹ nutrient solution was the most effective in terms of overall and spring production. However, the autumn and winter yields were not affected by the buffer EC. Fruit quality did not change with the cultural cycle, but the berries harvested in the spring had higher vitamin C and sucrose content and lower nitrate content compared with berries picked up in the winter. Fruit quality was also improved when the nutrient solution concentration increased. From the productive point of view, the cultural cycle choice should be made considering that 71% of the yield of the more productive summer-spring cycle derived from the spring harvest. Moreover, as regards the nutrient solution strength, 1.3 mS cm⁻¹ EC should be preferred during the spring season, whereas the 2.2 mS cm⁻¹ EC proved to be best in the winter in terms of fruit quality.     

AgNO_3对草莓试管苗生长及抗氧化酶活性的影响

为了探讨重金属离子对果树的毒性机制,以草莓(Fragaria ananassa Duch．)主栽品种丰香(Toyonoka)和章姬(Akihime)组培苗为外植体,研究了不同浓度AgNO3对草莓生长及抗氧化酶活性的影响。结果表明,1／2MS培养基中有AgNO3存在时,2个草莓品种的根干质量和根长明显增加,根系活力随着AgNO3浓度的增加而增加,1．0 mg／L时达最大值,而根系含水量则随着AgNO3浓度的增加逐渐降低。AgNO3浓度为0．5-1．0 mg／L时,植株株高和干质量逐渐下降,而叶绿素、可溶性蛋白的含量和抗氧化酶的活性则逐渐增加。叶片中MDA的含量、O2-的产生速率、脯氨酸的含量和IAA氧化酶的活性随着AgNO3浓度的增加而增加,而IAA的含量则逐渐降低。     

土壤高温处理对连作草莓根系呼吸代谢及植株发育的影响

为探讨草莓连作障碍机理,模拟太阳能消毒设置5个连作土壤高温灭菌处理,研究不同处理对草莓根系呼吸代谢及植株生长发育的影响。结果表明,连作土壤经高温灭菌后,各处理土壤中细菌和真菌数量都显著降低,经70℃高温连续20 d处理的土壤中真菌甚至消失,且对草莓根系呼吸代谢及植株发育的促进效果最明显;70℃高温连续10 d处理及55℃高温连续20 d处理对草莓植株生长、根系活力和根系总呼吸速率都具有不同程度促进作用,前者依然以PPP呼吸途径为主,后者的TCA呼吸途径是PPP呼吸途径的1.34倍;连作土壤55℃高温连续10 d处理作用效果最差。可见连作土壤高温灭菌后,土壤微生物数量减少,促进草莓根系呼吸代谢及植株生长,减轻了草莓的连作障碍,进而证明了土壤微生物是引起草莓连作障碍的重要因素之一。     

“爱乐壮”氨基酸肥料对大棚草莓叶片光合效率和产量的影响

【目的】为了验证"爱乐壮"氨基酸肥料在果树生产中应用的可能性,【方法】以大棚栽培‘红颊’草莓为试材,比较了叶面喷施稀释1 000倍和500倍"爱乐壮"氨基酸肥液对草莓叶片叶绿素含量、光合效率以及果实累积产量的影响。【结果】结果表明,与对照相比,不论在喷施后半个月还是1个月,2种浓度的"爱乐壮"肥液均能提高草莓叶片叶绿素相对含量(SPAD)、净光合速率(Pn)、光合性能指数(PIABS)、PSⅡ反应中心吸收光能用于电子传递的量子比率(φE0)、单位受光面积有活性反应中心数量(RC/CS)、单位活性反应中心电子传递能量(ET0/RC)和捕获激子将电子传递到QA-下游其他电子受体的概率(ψ0),同时降低K相可变荧光占J相可变荧光的比例(Wk)、PSⅡ反应中心QA被还原的最大速率(Mo)和单位活性反应中心耗散能量(DIo/CS)。在喷施后2个月,"爱乐壮"对叶片光合的效应逐渐消失,而草莓产量则显著增加。【结论】因而建议,在大棚草莓生产过程中,1个月喷施1次"爱乐壮"肥料,可以有效提高叶片光合性能,增加产量,提高效益。     

Influence of growth conditions on yield,quality and diseases of strawberry (Fragaria x ananassa Duch.) var Ofra and Chandler under mid hills of Sikkim Himalaya

Field experiments were conducted during 2005–09 at ICAR Sikkim Centre, Tadong, East Sikkim, India at an altitude of 1400 m amsl to identify the suitable environment for high production of good quality fruits with less diseases for strawberry varieties Ofra and Chandler. Both the varieties were grown under low cost polyhouse, plastic tunnel and open conditions. Maximum number of flower trusses per plant was recorded in Chandler under open condition (13.0) followed by plastic tunnel (12.7). The maximum number of fruits per inflorescence was found in Ofra (7.12) under polyhouse while maximum number of runners per plant was observed in Ofra (12.3) in open conditions. Plastic tunnel with Ofra produced highest fruit weight (26.2 g), fruit length (5.5 cm) and fruit diameter (3.9 cm). Best fruit quality in terms of TSS (6.8%), lower acidity (0.83%) and total sugar (6.3%) was observed in Chandler under plastic tunnel conditions. The highest total fruit yield was recorded with Ofra under plastic tunnel (40.2 t/ha) but the maximum marketable yield was obtained in Chandler under plastic tunnel (35.3 t/ha). Diseases were found to be less prevalent in tunnel as compared to polyhouse and open conditions.     

UV-B增强下6-BA、GA_3对油桃光合和抗氧化酶活性的影响

【目的】为探讨UV-B增强下植物生长调节剂对油桃光合作用的调控,【方法】以‘中油桃8号’为试材,研究了叶面喷施6-BA和GA3对UV-B增强下油桃光合特性和抗氧化酶活性的影响。【结果】结果表明,补充15μW.cm-2的UV-B辐射后,油桃的净光合速率下降,叶绿素a含量增加;补充30μW.cm-2的UV-B辐射,净光合速率和叶绿素a含量受到明显抑制,叶绿素b略有下降。喷施50 mg.L-16-BA和GA3可有效提高UV-B增强下叶片的Pn和叶绿素a、b含量。50 mg.L-16-BA处理14 d后,UV-B增强下叶片的SOD、POD活性明显上升,MDA含量显著下降,类黄酮含量与对照无显著差异;而GA3处理则提高了叶片的类黄酮含量,但MDA和抗氧化酶活性无显著变化。【结论】UV-B辐射增强下,6-BA对油桃光合特性的促进可能与SOD等抗氧化酶活性的提高有关。     

闭锁室内水分、养分及光照强度对番茄幼苗生长的影响

以中杂9号番茄为供试品种,采用72孔穴盘,在闭锁型育苗系统内进行番茄穴盘育苗的不同水分、养分及光照强度试验,测定番茄幼苗叶片数、株高、茎粗、地上部和地下部干质量、根冠比、壮苗指数、叶绿素含量等指标。结果表明,闭锁型育苗系统内基质相对含水量为70%～80%、每2d每盘浇灌1次1倍山崎配方营养液500mL和光照强度为320μmol.m-2.s-1时,幼苗生长明显好于其他处理。     

等渗Ca(NO3)2和NaCl对番茄幼苗生长的影响

 等渗Ca(NO₃)₂和NaCl溶液对番茄幼苗具有不同的盐效应。28、56 mmol/L Ca (NO₃)₂溶液对其生长的抑制作用小于等渗的NaCl 溶液, 而84 mmol/L Ca (NO₃)₂溶液对幼苗生长的抑制程度与等渗的NaCl 溶液无显著差异。Ca(NO₃)₂主要通过渗透胁迫影响植株生长;而NaCl主要通过离子胁迫抑制植株的生长, 包括细胞质膜结构的破坏和K吸收的减少。     

Pre-harvest foliar application of calcium and boron influences physiological disorders,fruit yield and quality of strawberry (Fragaria × ananassa Duch.)

Studies were conducted in ‘Chandler’ strawberry to determine if pre-harvest foliar application of Ca, B or their combination influences physiological disorders, fruit yield and quality or not. For this, treatments consisted of (i) five sprays of calcium as CaCl₂ (first spray was performed at the petal fall stage and later at 7 days interval), (ii) three sprays of boron as boric acid (first spray at the beginning of flowering and later at 15 day interval), (iii) combination of (i) and (ii), and (iv) plants sprayed with water served as the control. Results indicated that fruit harvested from plants, which were sprayed either with Ca or Ca + B had significantly lesser incidence of albinism (6.7 and 6.5%), and grey mould (1.3 and 1.2%) than those harvested from plants sprayed either with B alone or in control. Although, B alone could not influence the incidence of albinism and grey mould, but it reduced fruit malformation (3.4 and 3.1%) significantly. Further, Ca, B or their combination had not influenced the individual berry weight, but marketable fruit yield differed significantly. The lowest marketable fruit yield (149.3 g/plant) was recorded in plants under control, and the highest (179.2 g/plant) in plants sprayed with Ca + B. Similarly, such fruit were firmer; had lower TSS, higher acidity and ascorbic acid content at harvest than those in control. Similarly, such fruit after 5 days storage were firmer and brighter, and have significantly lower TSS (7.9 and 7.8%); higher ascorbic acid content (43.7 and 45.0 mg/100 g pulp) and acidity (1.08 and 1.07%) than those in control or those receiving B alone. Incidence of grey mould was significantly lesser in fruit, which received Ca (2.2%) or Ca + B (1.9%) than those, which received either B (8.1%) alone or those in control (8.4%). Our studies indicated that pre-harvest foliar application of Ca + B is quite useful for reducing the incidence of disorders and getting higher marketable yield in ‘Chandler’ strawberry.     

主干形桃树对光截获能力和果实产量品质的影响

以6a生八月脆桃为试材,在果实成熟期观测分析了2种树形(主干形和开心形)对光截获能力和果实产量及品质的影响。结果表明,2种树形同一层次的平均单果质量、着色指数、光洁度差异不显著;果实硬度和可溶性固形物有显著差异,果实硬度表现为主干形﹥开心形,可溶性固形物则表现为开心形﹥主干形。对光截获能力的影响表现为主干形>开心形;叶面积指数、果实产量指标均表现为主干形高于开心形;果实产量是开心形的2.11倍。桃树主干形是高光效、高产树形。     

外源蔗糖对NO3- 胁迫下叶用莴苣生长及品质的影响

采用水培方法,以常规营养液（7.5 mmol·L^-1 NO₃^-）、叶面喷施清水作为对照, 在75 mmol·L^-1 NO₃^-胁迫下,通过叶面喷施0 mmol·L^-1（T1）、1 mmol·L^-1（T2）、5 mmol·L^-1（T3）的蔗糖,研究外源蔗糖对NO₃^-胁迫下叶用莴苣生长及品质的影响。结果表明：T1 处理叶用莴苣的生长受到显著抑制,同时显著降低了VC 含量。外源蔗糖处理可以缓解NO3- 胁迫对叶用莴苣生长的抑制作用,提高VC 含量,同时可略降低硝酸盐含量,其中T2 处理效果较好。与对照相比,T2 处理和T3 处理均可降低叶用莴苣可溶性蛋白含量,T3 处理可提高可溶性糖含量,但差异均不显著。     

不同菌剂对丰香组培苗生长发育和白粉病抗性的影响

以丰香草莓微繁殖苗为试材,分别以重茬土和混合基质为栽培基质,比较研究了丛枝菌根真菌(AMF)菌剂、木霉(Trichoderma)菌剂和有效微生物群(EM)菌剂对草莓植株生长发育和生理生化指标、产量、白粉病抗性等的影响。结果表明,无论是重茬土还是混合基质,供试的3种微生物菌剂处理后均可促进丰香草莓微繁殖苗的生长势,提高草莓叶片叶绿素、蛋白质、可溶性糖和淀粉质量分数,增加果实产量,其中AMF菌剂处理的效果显著,其叶面积和叶片叶绿素质量分数均是CK的1.5倍左右,产量比CK增加68.6%(重茬土)、39.5%(混合基质)。AMF菌剂处理和木霉菌剂处理植株中β-1,3-葡聚糖酶的活性是CK植株的2.6～5.5倍。在提高草莓微繁殖苗白粉病抗性上,木霉菌剂处理的效果最为显著,在重茬土和混合基质上,木霉菌剂处理植株的病情指数分别为36.7和19.2,分别为CK植株的51.8%和59.1%。