THE EFFECT OF NITROGEN SOURCES ON YIELD AND QUALITY OF SALAD ROCKET GROWN IN DIFFERENT MONTHS OF THE YEAR

The effects of months of the year and nitrogen (N) sources on salad rocket (Eruca sativa Mill.) yield, quality, and nitrate accumulation was investigated during the years 2002 and 2003. In both years, seeds were sown on the first day of April, May, June, July, August and September. Three different nitrogen sources were used: farmyard (cattle) manure (100 tonnes·ha^?1), calcium nitrate [Ca(NO₃)₂]-15.5% N (150 kg N·ha^?1) and ammonium sulfate [(NH₄)₂SO₄)]-21% N (150 kg N·ha^?1). Yield, leaf color, dry matter, vitamin C and total glucosinolate content and nitrate accumulation was assessed. Growing months affected all the assessed parameters significantly both years, with the exception of hue angle in 2003, whereas nitrogen source only influenced yield and nitrate accumulation in 2003. In both years the highest yield was obtained in April, but vitamin C and total glucosinolate contents were higher during summer months, and leaves were slightly darker colored. Chemical fertilizers increased the yield compared to farmyard manure; however, they also increased nitrate accumulation slightly, without any significant difference between them. Nitrate accumulation never exceeded 300 mg kg^?1 fresh weight (FW), which is well below the acceptable daily intake of 3.7 mg nitrate per kg^?1 bodyweight set by European Commission's Scientific Committee on Food.     

INFLUENCE OF NITROGEN AND SULFUR ON YIELD AND SEED QUALITY OF THREE CANOLA CULTIVARS

In order to investigate the effect of nitrogen (N) and sulfur (S) fertilizers on yield and seed quality of three canola cultivars, a factorial based on randomized complete block experiment was conducted during 2005–2006 in Iran. Treatments included four nitrogen rates (0, 75, 150, and 225 kg N ha^?1 source of urea), four sulfur rates (0, 100, 200, and 300 kg S ha^?1), and three cultivars (‘Pf’, ‘Option-500’, and ‘Hyola-401’). Results indicated cultivar had a significant effect on all studied traits. ‘Option-500’ and ‘Hyola-401’ cultivars had the highest seed yield, protein content, and N:S ratio in seed. The levels of 150 and 220 kg N ha^?1 resulted in the maximum protein content. Increasing N levels resulted in N content and decreased the oil content. The interaction effect between S and N levels showed the highest N content in seed was obtained with 300 kg S ha^?1 and 225 kg N ha^?1.     

硫肥对棉花蕾铃脱落及产量的影响

本文就硫素与棉花蕾铃脱落和产量的关系进行了研究。试验结果表明,在传统施肥量330kg N/hm2,60kg P/hm2情况下,棉花蕾铃脱落率达70.3%;在增加氮磷肥施用量并补施硫酸钾情况下,棉花蕾铃脱落率为68.5%,说明硫酸钾有效降低了棉花的蕾铃脱落率。在传统施肥量基础上施用硫磺30.0kg/hm2对棉花的蕾铃脱落没有影响,但是增加了棉花单株结铃数、提高了产量。与不施硫相比,施硫使棉花单株结铃数增加14.7%,产量增加了15.7%。上述结果说明,在新疆高产棉田中使用单质硫肥能够进一步增加棉花产量。     

EFFECT OF NITROGEN APPLICATION ON GROWTH PARAMETERS,YIELD AND LEAF NITRATE CONTENT OF GREENHOUSE LETTUCE CULTIVATED DURING THREE SEASONS

Lettuce (Lactuca sativa L., cv. ‘Parris Island’) was grown hydroponically in autumn, winter and spring under five levels of nitrogen (N) fertilization. Plant biomass was highest in spring and lowest in autumn at N rates of 200 and 260 mg L^?1, respectively. Increasing N application correlated positively with rates of photosynthesis, transpiration, stomatal carbon dioxide (CO₂) conductance and leaf chlorophyll concentration. Photosynthetic rate, stomatal CO₂ conductance, and chlorophyll a/b ratio were higher in spring than in autumn or winter. Nitrate concentrations within the leaves increased with increasing N application in all seasons. It is concluded that lettuce growth and yield is higher in spring than in winter or autumn due to enhanced photosynthesis thanks to increasingly favorable photoperiod. Regardless of season, high N rates promote yield but increase leaf nitrate concentrations. Therefore, for the production of healthy produce the recommended N rate should be based not just on yield but also on the nitrate content.     

硫肥对双低油菜产量与品质的影响

在澳大利亚新南威尔士州缺硫土壤上进行了硫、氮不同水平组合对双低油菜(Canola)的影响试验。结果表明,试验条件下施用硫肥可显著提高油菜产量及含油量。低硫(S10)或无硫(So)条件下,一定量的氮肥(N80)可提高子粒内的含硫量,但高硫条件下,高量氮肥则降低含硫量。植株体内的含硫量随生育进程趋于降低。施硫处理在抽苔期出现一吸硫高峰,而对照呈指数下降;但在开花期与角果充实期则保持相对稳定。氮肥对生长前期(莲座期与抽苔期)植株(茎、叶)含硫量的影响不显著,而中、后期(开花、角果充实期),则随施氮量的增加而显著降低。高量氮肥(N160)会降低子粒内的硫代葡萄糖甙含量;施硫,特别是在高施硫量条件下,其含量则明显增加,但仍远低于子粒硫代葡萄糖甙40mol/g的标准,因而不会影响脱油饼粕的饲喂质量。     

STUDIES ON DIFFERENCES OF NITROGEN EFFICIENCY AND ROOT CHARACTERISTICS OF OILSEED RAPE (BRASSICA NAPUS L.) CULTIVARS IN RELATION TO NITROGEN FERTILIZATION

Differences of nitrogen efficiency of oilseed rape (Brassica napus L.) cultivars and their physiological properties were studied in a pot experiment, and the ratio of seed yield with no nitrogen supplied to that with normal nitrogen supply was adopted as a nitrogen efficiency coefficient. Results showed that the nitrogen efficiency coefficient determined for eight oilseed rape cultivars varied from 0.37 to 0.69, the ratio of nitrogen uptake amounts per plant, nitrogen transfer velocity from stems and leaves to seeds, and nitrogen physiological efficiency of oilseed rape cultivars under nitrogen stressed condition differed from with normal nitrogen supply. The higher the nitrogen efficiency of a cultivar, the higher the ratio of N uptake in no nitrogen to with N supplied. Under low nitrogen-supplying conditions, high nitrogen efficiency cultivars had longer roots, more lateral roots, higher amounts of reuse of nitrate from stem and leaves, and higher nitrate reductase activities in leaves.     

~(60)Coγ辐射对菜心离体培养的影响

菜心种子经~(60)Coγ射线辐照在离体培养中茎尖存活率随剂量增大而下降 ,茎尖增殖、子叶愈伤组织诱导和愈伤组织分化受到抑制 ;外植体龄影响离体培养中的辐射效应 ;小于 50Gy直接辐照离体培养中的茎尖促进芽的增殖。从对离体培养的效应看 ,对种子的适宜辐射剂量是200Gy左右 ,经催芽种子为 50～100Gy,离体培养茎尖可用 40～ 70Gy。     

EFFECT OF EXTERNAL NITRATE CONCENTRATIONS ON NITRATE EFFLUX FROM ROOTS AND ACCUMULATION IN TWO BRASSICA NAPUS L. CULTIVARS

The nutrient solution was replaced on day 72 after sowing, and then the relationship between nitrate (NO₃)-nitrogen(N) concentration in plants and nitrate efflux from roots of two oilseed rape cultivars (Brassica napus L. cv. ‘Zhongyou 821’ (‘ZY821’) and “D89”) was compared on days 73, 74, and 75, respectively. Nitrate-N concentration in petioles of “ZY821” was significantly greater than in “D89”. Nitrate-N concentrations in the nutrient solution and petioles were high on day 73 and nitrate efflux from roots of “D89” was greater than from “ZY821”. On day 75, as nitrate-N concentrations in the nutrient solution declined, both the maximum cumulative efflux and efflux rate of “ZY821” was higher than “D89.” We hypothesized that “ZY821” could remobilize more nitrate-N from the petioles to meet its N needs. This would result in a decline in translocation of nitrate from roots to shoots and an increase in root cytoplasm nitrate concentrations and root efflux.     

INTERACTIVE EFFECTS OF SALINITY AND N ON PEPPER (CAPSICUM ANNUUM L.) YIELD,WATER USE EFFICIENCY AND ROOT ZONE AND DRAINAGE SALINITY

The aim of this study was to determine the salt tolerance of pepper (Capsicum annuum L.) under greenhouse conditions and to examine the interactive effects of salinity and nitrogen (N) fertilizer levels on yield. The present study shows the effects of optimal and suboptimal N fertilizer levels (270 kg ha^?1 and 135 kg ha^?1) in combination with five different irrigation waters of varying electrical conductivity (EC) (EC_iw = 0.25, 1.0, 1.5, 2.0, 4.0, and 6.0 dS m^?1) and three replicates per treatment. At optimal N level, yield decreased when the irrigation water salinity was above EC_iw 2 dS m^?1. At the suboptimal N level, a significant decrease in yield occurred only above EC_iw 4 dS m^?1. At high salinity levels the salinity stress was dominant with respect to yield and response was similar for both N levels. Based on the results it can also be concluded that under saline conditions (higher than threshold salinity for a given crop) there is a lesser need for N fertilization relative to the optimal levels established in the absence of other significant stresses.     

硼对油菜花器官发育和结实性的影响

在缺硼和正常供硼条件下，油菜花器官的含硼量明显高于叶片，尤其是雌蕊和雄蕊中的含量可达同期叶片的两倍左右；硼过量时则以叶片含硼量最高。缺硼导致雄蕊长度，干重下降，花药绒毡层异常，花粉囊化化受阻。缺硼和硼过量均使油菜单株有效角果数，每角果籽粒数及结角率，结籽率，油菜籽产量下降。硼对角果的胚珠数没有影响。与宁油７号相比，宁油８号油菜品种更易受缺硼和过量硼的影响。     

SEED YIELD AND YIELD COMPONENTS RESPONSE OF RAPE (B. NAPUS) VERSUS MUSTARD (B. JUNCEA) TO SULFUR AND POTASSIUM FERTILIZER APPLICATION IN NORTHWEST PAKISTAN

Improper sulfur (S) and potassium (K) fertilizer management, particularly with continued soil nutrient mining, is one of the major factors contributing to low seed yield of canola in northwestern Pakistan. A field experiment was conducted in 2007?2008 on a S and K deficient clay loam soil at the Research Farm of NWFP (Northwest Frontier Province) Agricultural University, Peshawar, Pakistan, with an objective to determine seed yield and yield components response of Brassica oilseed rape versus mustard to S and K application. Twenty treatments in a randomized complete block design were consisted of two oilseed rape (B. napus canola) and mustard (B. juncea canola) genotypes at three rates each of S (15, 30, and 45 kg S ha^?1) and K (30, 60, and 90 kg K ha^?1) fertilizers plus one control (no S and K applied). Seed yield and yield components increased significantly with K and S fertilization as compared to the zero-S/zero-K control. Both genotypes responded positively for seed yield and yield components to K and S fertilization, but the magnitude of response varied with levels of S and K, as well as combined K + S applications. It is concluded that a combination of 60 kg K + 30 kg S ha^?1 would improve seed yield and yield components of rape and mustard in the study area and contribute significantly to increased production. Growing B. napus was better than B. juncea in the study area, because B. napus produced significantly higher seed yield and yield components than B. juncea, indicating that yield components are the most important criteria for selection of Brassica genotypes for higher seed yield.     

不同施肥模式对水稻生理特性、产量及其N肥农学利用率的影响

以水稻品种金优207为材料,对不施氮肥(T1)、试验区当地农民习惯氮肥用量(T2:尿素,纯N187.5 kg/hm2)和在农民习惯施氮量基础上减量配施氮肥(T3:氮减少20%,30%农民习惯用化肥+20%习惯用量的有机肥+30%习惯用量的缓释肥,纯N 150kg/hm2)3种施肥模式下水稻不同生育期的生理特性、产量及其...     

EFFECT OF BORON-DOPED GOETHITE ON SOIL ACIDITY,DIFFERENT FORMS OF MANGANESE IN RED SOIL AND THE GROWTH OF RAPE (BRASSICA NAPUS L.) SEEDLINGS

Rape (Brassica napus L.) seedling pot experiments were performed with a red soil treated with goethite which had boron (B) either adsorbed (ad-B-goethite) or occluded (oc-B-goethite). Soil acidity, different forms of manganese in the soils and different elements content of the rape seedlings were determined. It was found that the addition of boron-containing goethite to the soils resulted in increased rape growth, elevated soil pH and decreased exchangeable acidity. Compared with the control, boron-containing goethite elevated the content of exchangeable manganese (Mn) (EXC-Mn), organic matter bound Mn (OM-Mn), reducible oxide Mn (RO-Mn) and residual Mn (RES-Mn) which were difficult to use for plant. Low labile organic matter was significantly correlated with easily reducible oxide Mn (ERO-Mn) (P < 0.01) and RO-Mn (P < 0.05). Middle organic matter and soil pH was significantly (P < 0.05) correlated with RES-Mn. Stepwise regression was used to select the combination of variables that best estimates shoot and root dry weight of rape seedling. Among them, soil pH, EXC-Mn, OM-Mn, RO-Mn and RES-Mn significantly influenced the dry weight of rape seedlings. The addition of boron-containing goethite improved the uptake of iron (Fe), calcium (Ca), magnesium (Mg), and copper (Cu) element and decreased the uptake of Mn and zinc (Zn) element in rape seedling. The results suggested that boron-containing goethite could provide a better soil acidity environment for plant growth; it was also an important agent increasing a part of manganese difficult to use for plant and reducing the activity of soil manganese, which was beneficial to altering rape seedling growth.     

打顶后涂抹生长素对长绒棉生长和蕾铃脱落的影响

与传统打顶处理相比,打顶后涂抹浓度为3×10-2mmol.L-1的α-萘乙酸(NAA),促进了上部植株的生长,植株上部生物量、成铃率分别比传统处理提高148.6%和96.6%,空果枝数降低52.6%,蕾铃脱落率降低43.1%;单株籽棉产量增加了26.4%。上述结果说明,生产中普遍存在的中后期“早衰”和“中空”现象与棉花打顶导致顶端优势丧失有关,打顶后涂抹NAA使植株的顶端优势得到一定恢复。     

基本苗数和底追肥比例对冬小麦籽粒产量和蛋白质组分的影响

以中任1号小麦为试验材料,采用二因素随机区组设计,研究了基本苗和氮肥施用策略对小麦植株性状、产量和蛋白质组分的影响。结果表明,不同基本苗数和氮肥底/追比例的处理间株高、穗长、产量、千粒重、容重均有显著差异。穗长与穗粒数呈极显著正相关(r=0.931**)。随基本苗增加,穗长、穗粒数和千粒重逐渐减少,处理间差异显著。容重有随基本苗增加而升高的趋势。对产量而言,基本苗以450万/hm2时较高,但与300万/hm2和375万/hm2基本苗处理间的产量差异不显著,因此,生产中在偏晚的播期内,可以根据实际播种时间和地力条件,在300~450万/hm2基本苗范围内进行调整。不同蛋白组分对基本苗处理的反应有别,在基本苗较少时清蛋白和球蛋白含量较低,而谷蛋白和总蛋白含量较高。清蛋白、球蛋白、醇溶蛋白在各追肥比例处理间差异不显著,谷蛋白和总蛋白含量处理间差异显著,且均以底追比例3∶7的处理含量最高。总蛋白含量有随追肥比例增加而提高的趋势。     

叶面施硅对西芹养分吸收、产量及品质的影响

采用田间小区试验,研究了叶面喷施不同形态硅对日光温室西芹生长发育、产量和品质的影响。结果表明:叶面施硅能显著促进西芹生长发育,调节不同生育时期西芹对氮、磷、钾养分的吸收。与对照相比, 采收期施硅植株株高、茎粗、叶绿素和叶片可溶性糖含量分别增加6.33%~9.22%,10.93%~14.50%,6.64%~9.26%和10.36%~13.12%; 叶片氮含量减少2.90%~6.35%;有机硅处理叶片磷含量增加41.39%;钾含量增加18.23%~77.65%;显著提高西芹单株重和产量,分别增加11.36%~17.64%和12.61%~17.52%;植株Vc含量增加24.82%~61.19%,硝酸盐含量降低3.60%~15.62%。结果说明硅肥施用一定程度上能够改善西芹的品质。     

正常和高铵条件下氯化钠对万寿菊生长、开花和代谢的影响

在温室中以养分平衡的肥料组合和含250mg/L NH_4~+的组合栽培万寿菊(Tagetes patula L.)。每种组合中以一半植株每天每盆加250 mL 27.5 mmol/L NaCl溶液,进行盐胁迫处理。盐处理结果,使每株鲜重、株高和开花数都减少。盐处理2周后,根、叶细胞膜相对透性显著增加,叶子热处理渗出物中游离NH_4~+、根渗出物中Na~+。以及叶子中的过氧化物酶、Mg~(2+)-ATP酶和Ca~(2+)-ATP酶活性都明显提高,而根、叶渗出液的pH和蛋白质含量显著降低。根渗出物中游离NH_4~+、K~+和Ca~(2+)含量,叶子中叶绿素、可溶性蛋白质、无机磷和多酚氧化酶活性也下降,但未发现叶子渗出物中Na~+有所增加。在正常营养条件下,盐胁迫对叶子中的类胡萝卜素和花青素影响较小,但高NH_4~+处理使这些色素含量显著降低。高NH_4~+一般使NaCl的效应加剧。     

辐照对黄籽油菜种子活力、超氧物歧化酶活性和脂质过氧化作用的影响

用~(60)Coγ射线辐照2个杂交组合高世代材料中分离出的黄籽和黑籽甘蓝型油菜(Brassica napus L.)近等基因系种子,测定辐照前、后种子在发芽过程中的种子活力,超氧物歧化酶(SOD)和脂质过氧化产物丙二醛(MDA)的变化。结果表明,辐照后,黄籽比黑籽的SOD活性上升幅度小,MDA含量上升幅度大,种子活力下降较多。黄籽油菜种子的辐射敏感性比黑籽强;油菜的辐射抗性或敏感性不仅与体内保护酶水平有关,也可能与种皮的特殊保护结构和保护物质有关。     

EFFECT OF THE ECTOMYCORRHIZAL FUNGUS PAXILLUS INVOLUTUS ON GROWTH AND CATION (POTASSIUM,CALCIUM, AND MAGNESIUM) NUTRITION OF PINUS SYLVESTRIS L. IN SEMI-HYDROPONIC CULTURE

A semi-hydroponic culture was used to compare growth and cation nutrition of mycorrhizal (Paxillus involutus) and non-mycorrhizal Scots pine seedlings. When roots and hyphae grew together, concentrations and contents of macronutrients in needles and roots were not significantly different between mycorrhizal and non-mycorrhizal plants. When grown in two separate compartments, root potassium (K) concentrations, concentrations and contents of calcium (Ca) in needles and roots, needle nitrogen (N) concentrations, total N content and contents of root K and Mg were significantly reduced in mycorrhizal plants. Whereas ¹⁵N abundance increased in roots of mycorrhizal plants. The results indicated that the extraradical mycelium of the fungus strain used was able to transport N to the plant but did not contribute to long-term cation uptake and growth of host plants. An insufficient supply of macro-elements [N, phosphorus (P)] may account for the reduced growth of mycorrhizal plants and the differences in cation uptake between mycorrhizal and non-mycorrhizal plants.