The effects of rates of supply of nitrogen, phosphorus, potassium and magnesium on leaf and stem growth, flowering and 'topple' of Golden Harvest and Elmus tulip

In factorial nutrition experiments with three rates of nitrogen, phosphorus and potassium—with some additional treatments with magnesium—on two bulb sizes of Golden Harvest and Elmus tulip, the effect of nitrogen was outstanding. Flowering was retarded by low and high rates of nitrogen supply. Increased nitrogen decreased the length of the first internode of Elmus. Mineral deficiency symptoms in leaf and stem showed minor varietal differences.
Elmus tulips receiving amounts of calcium normally considered adequate developed 'topple' when given no nitrogen especially when combined with high potassium: these treatments also induced stem contortion in Golden Harvest, which appeared to be an analogous disorder to 'topple'.     

The residual effect of previous nutritional treatments on the growth and composition of tulips supplied with complete nutrients in sand culture

Tulip bulbs produced in sand culture with three rates each of nitrogen, phosphorus and postassium in factorial combination were subsequently grown for one season with complete nutrients in order to study the residual effects of the previous treatments. The bulbs included the progeny of large (II cm). and small (7 cm.) Golden Harvest after one season of differential nutritional treatments and of large Golden Harvest (II cm). and Elmus (12 cm.) after tow such seasons. The early stages of growth, became less apparent by early March, but many of the bulbs previously deprived of nitrogen produced only single leaves and no flowers. The favourable effect of nitrogen on the weights of Golden Harvest bulbs was less marked at lifting than at planting time, but remained highly significant. The yield of Elmus bulbs showed particularly marked responses to both nitrogen and phosphorus. Other residual effects included decreased leaf area of bulbs previously deprived of nitrogen and phosphorus, and slightly earlier flowering with increasing levels of nitrogen. Growth in complete nutrient solution decreased the differences in amounts of major nutrients in the bulbs. The percentage of nitrogen in Golden Harvest bulbs, and of phosphorus and potassium in both varieties, nevertheless increased significantly with the levels of these nutrients in the previous seasons.     

水稻物质生产与氮、磷、钾、硅素积累特点及其相互关系

大田条件下研究了30个水稻基因型的干物质与N、P、K、Si积累特性及其相互关系.结果表明,水稻干物质积累总量随N、P、K和Si积累总量的增加呈直线增加,其相关系数早季和晚季均达极显著水平.同时,N、P、K、Si积累的平衡有利于干物质积累,干物质积累量随NBI(养分平衡指数)直线增加,随NDI(养分偏离指数)直线下降.30个水稻品种平均N、P、K、Si积累总量比值早季为3.76:1:4.55:7.10,晚季为2.88:1:4.54:8.09.干物质积累能力以中期最强,前期最弱,而N积累能力却以前期最强,后期最弱.水稻抽穗前积累的干物质主要分配在茎鞘中,当抽穗期茎鞘比率达到最大时,茎鞘重约为叶片重的2倍,而抽穗前积累的N主要分配在叶片中,叶片中N的分配比率全生育期均比干物质分配比率高.成熟期积累的干物质、N和P主要分配在穗部,早、晚季稻的平均分配比率分别为58.01%、66.42%和70.06%,而K主要分配在茎鞘中,早、晚季稻的平均分配比率为62.08%.早季Si在茎中的分配比率(43.11%)最大,而晚季却以穗中的分配比率(46.99%)最大.     

水稻物质生产与氮、磷、钾、硅素积累特点及其相互关系

大田条件下研究了30个水稻基因型的干物质与N、P、K、Si积累特性及其相互关系．结果表明,水稻干物质积累总量随N、P、K和Si积累总量的增加呈直线增加,其相关系数早季和晚季均达极显著水平．同时,N、P、K、Si积累的平衡有利于干物质积累,干物质积累量随NBI(养分平衡指数)直线增加,随NDI(养分偏离指数)直线下降．30个水稻品种平均N、P、K、Si积累总量比值早季为3．76：1：4．55：7．10,晚季为2．88：1：4．54：8．09．干物质积累能力以中期最强,前期最弱,而N积累能力却以前期最强,后期最弱．水稻抽穗前积累的干物质主要分配在茎鞘中,当抽穗期茎鞘比率达到最大时,茎鞘重约为叶片重的2倍,而抽穗前积累的N主要分配在叶片中,叶片中N的分配比率全生育期均比干物质分配比率高．成熟期积累的干物质、N和P主要分配在穗部,早、晚季稻的平均分配比率分别为58．01％、66．42％和70．06％,而K主要分配在茎鞘中,早、晚季稻的平均分配比率为62．08％．早季Si在茎中的分配比率(43．11％)最大,而晚季却以穗中的分配比率(46．99％)最大．     

Relationships between Bulb Size, Apex Size and Flowering in Bulbous Iris cv. Ideal

Large, retarded bulbs of the Iris cv. Ideal flower readily after exposure to appropriate preplanting conditions, whereas smaller bulbs flower with decreased frequency. Flower initiation occurs when apices from large, retarded bulbs are cultured on either Murashige-Skoog medium supplemented with gibberellic acid, or on the same medium without gibberellic acid on which scales from large bulbs have been incubated. Since floral initiation seldom occurs in explants from small bulbs, it is likely that reduced flowering of small bulbs relates in part to characteristics of the apical meristem. Apical dome diameter is one characteristic of retarded (and freshly dug) bulbs that is positively correlated with bulb size. However, whereas prolonged storage at retarding temperature increases the frequency of flowering of smaller bulbs, there is not a concomitant increase in apical dome diameter. Moreover, the ratio of apical dome diameter to bulb size in freshly dug bulbs does not increase measurably with later digging date indicating that apical dome size is not correlated with bulb maturity.     

Effects of infection with narcissus mosaic, narcissus yellow stripe and tobacco rattle viruses on the growth and flowering of narcissus cv. 'Minister Talma'

Three plots were planted with similar-sized narcissus bulbs: healthy; infected with narcissus mosaic virus (NMV); and infected with narcissus yellow stripe + tobacco rattle virus (NYSV+TRV). No effects of infection were observed on flower number, diameter, paracorolla length or flower dry weight, but the flower stalks were shorter in the infected plants. NMV-infected plants produced slightly blemished flowers, and 74% of the NYSV + TRV-infected flowers were of poor quality. Virus infection delayed leaf growth and loss of bulb dry weight early in the season and senescence in July. NYSV+TRV-infected plants were more affected than NMV-infected plants. However, maximum leaf area was similar for all plants. The maximum plant dry weight and the final weight of the bulb were not significantly affected by infection, but small differences, which could be cumulative in successive years would not have been detected. Differences in net assimilation rate, if any, were small.     

Mineral composition of Phragmites australis in Scottish lochs as related to eutrophication. I. Seasonal changes in organs

Monthly levels of nitrogen, phosphorus, potassium, sodium, calcium, magnesium and iron in the organs (root, rhizome, stem, leaf and panicle) of Phragmites australis were determined from March to November, 1975 in Forfar Loch (polytrophic), Balgavies Loch (eutrophic) and Loch of the Lowes (mesotrophic), Scotland. Generally no consistent seasonal changes in the mineral levels were detected for the root, rhizome and panicle. For the stem and leaf, the levels of nitrogen, phosphorus, potassium, calcium and magnesium rose to a peak before declining for the rest of the season. Consistently higher levels of tissue nitrogen, phosphorus, potassium and calcium were found in the Forfar plants over those of Balgavies and Lowes, reflecting the very eutrophic condition in Forfar Loch. The mineral compositions in the reeds in the present study were compared with similar studies in other areas.     

Control of smoulder (Botrytis narcissicold) in narcissus with fungicides

Smoulder, caused by Botrytis narcissicola, is the most widespread foliar disease of narcissus (Narcissus cultivars) in the UK and causes significant losses in bulb and flower yield. A range of current and novel fungicide treatments was examined to determine if control of the disease could be improved and to measure the effect of treatments on bulb yield. In assays on pot-grown plants, carbendazim+flusilazole, epoxiconazole, iprodione + thiophanate-methyl, tebuconazole and vinclozolin reduced lesion size by more than 90%, compared with untreated plants, when applied 1 day before inoculation with the fungus; vinclozolin and tebuconazole were also effective when applied 2 days after inoculation. In field experiments in Cambridgeshire and Lincolnshire, significant reductions were observed in secondary smoulder symptoms (leaf lesions and stem rot) following fungicide sprays. Spray programmes of the novel fungicides azoxystrobin, cyprodinil, kresoxim-methyl, tebuconazole and pyrimethanil were as effective, or more so, than the standard treatments (chlorothalonil, vinclozolin) used by growers. Mixtures of carbendazim + tebuconazole and azoxystrobin + tebuconazole also gave effective control of smoulder. Programmes of four to six sprays, using two or three fungicides with different modes of action, applied alternately, reduced smoulder by 35–69% and increased bulb yields by 7–59%. Although treatment around and after flowering resulted in the greatest control of secondary smoulder, treatment before flowering was required for the highest bulb yields. The choice of fungicides for use in spray programmes to provide effective and reliable control of smoulder, and the possibility of control using fewer sprays, are discussed.     

Temporal expression of effects of varying nitrogen supply on canopy growth, photosynthesis and fruit production for Actinidia deliciosa vines in the field

The effects of varying nitrogen supply on canopy leaf area, response of leaf net photosynthesis (A_n) to quantum flux density (Q), and fruit yields of kiwifruit vines (Actinidia deliciosa var. deliciosa) were examined in a two-year field experiment. Vines were grown with 0, 250 or 750 kg N ha^?1 year^?1. The responses to nitrogen supply were compared with responses to shade, to examine the impact of reduced carbon assimilation on canopy leaf area and fruit yields. Nitrogen supply did not affect significantly any of the measured variables during the first season of the experiment. In the second season, canopy leaf area was reduced significantly where nitrogen supply was limited. The quantum efficiency of photosynthesis (φ_q) increased from 0. 03 mol CO₂ mol^?1 Q soon after leaf emergence to more than 0. 05 mol CO₂ mol^?1 Q during the middle of the growing season. The quantum saturated rate of A_n (A_sat) also increased during the season, from 7–10 μmol CO₂ m^?2 s^?1 soon after leaf emergence, to 15–20 (μmol CO₂ m^?2 s^?1 during the middle of the growing season. φ_q and A_sat increased significantly with nitrogen supply at all measurement times during the second season. For vines with high nitrogen, fruit yields in both seasons were similar, averaging 3. 05 kg m^?2. Fruit yields in the second season were reduced significantly where nitrogen supply was limited, due to reduced fruit numbers. The relative effects of reduced leaf area and reduced leaf photosynthesis for carbon assimilation by nitrogen deficient vines were examined using a mathematical model of canopy photosynthesis for kiwifruit vines. Simulations of canopy photosynthesis indicated that effects on leaf area and on leaf photosynthesis were of similar importance in the overall effects of nitrogen deficiency on carbon assimilation. The effects of nitrogen supply on fruit numbers (i. e. flower development) preceded the measured effects on carbon assimilation, indicating that the nitrogen supply affected carbon partitioning to reserves in the first season.     

Effect of the Duration of the Vegetative Phase on Shoot Growth, Development and Yield in Pearl Millet (Pennisetum americanum (L.) Leeke)

Craufurd, P. Q. and Bidinger, F. R. 1988. Effect of the durationof the vegetative phase on shoot growth, development and yieldin pearl millet (Pennisetum americanum (L.) Leeke).–J.exp. Bot. 38: 124–139 The duration of the vegetative phase (DVP) in millet, whichis the major cause of variation in the crop duration, has markedeffects on the number of productive tillers per plant and onmainshoot (MS) and tiller grain yield. Daylength extensionswere used to vary the DVP and the effect on factors affectingpanicle (tiller) number per plant and panicle yield examinedin millet hybrid 841A x J104, grown in the field at Hyderabad,India. Tiller appearance, shoot leaf appearance and leaf area,and stem and panicle growth, in both MS and primary tillers(PTs), were monitored at frequent intervals over the season.At maturity grain yield per shoot was measured The concept of thermal time was used to describe shoot development.The rates of tiller appearance and shoot leaf appearance werelinearly related to thermal time and were not affected by DVPtreatments. The duration of the growth phase from panicle initiationto flowering (GS2) and from flowering to maturity (GS3) was320 and 390 degree days (°Cd), respectively. There was nodifference in rates of leaf or tiller appearance or developmentbetween MS and PTs. Tiller appearance, tiller leaf appearanceand tiller apical development all ceased at the same time inthe later initiated PTs, approximately 550 °Cd from sowing,shortly after rapid stem growth had begun. Tillers that didnot survive were all vegetative or in the early stages of reproductivedevelopment at this time The rate of accumulation of dry matter per plant was similarin all DVP treatments, but in the longer DVP treatments a greaterproportion of the dry matter was partitioned to the MS. Mainshootstem and panicle growth rates were increased by a longer DVP,as was grain yield on the MS, and these were related to increasedMS leaf area. Concurrently, growth rates and yields in laterinitiated tillers were reduced in relation to their leaf areas.Stem growth rate was proportionately increased more than paniclegrowth rate in the longer DVP treatments and this, combinedwith a longer duration of stem growth, resulted in greater stemdry matter at maturity and, therefore, in reduced harvest index.     

Effect of Bulb Size on the Growth of Tulips

A study of the growth in the field of tulip plants from bulbsof four different sizes showed marked differences of leaf areaand shoot dry weight, those produced by larger bulbs being thegreater. Relative growth rates of the smaller plants were higherthan those of the large ones; this was due to different proportionsof total plant weight being non-growing mother bulb, as therelative growth rates of the shoots were not affected by bulbsize. The relative growth rates of daughter bulbs were alsounaffected by the mother bulb size, being very similar to previouslydetermined values in other sites and seasons. The final bulbyield was proportional to daughter bulb weight early in theseason. It is suggested that daughter bulb weight, shoot weight,and leaf area are directly related to the size of the motherbulb, and controlled by the factors determining mother bulbsize during its development.     

The Levels of Nitrogen, Phosphorus, Potassium, Calcium and Magnesium in the Leaves of Cacao (Theobroma Cacao L.) as affected by Shade, Fertilizer, Irrigation, and Season

The results are given of chemical analyses of leaves collectedover a period of two years from cocoa trees in a field trialreceiving fertilizer, shade, and irrigation treatments. Thegreatest variation in concentration of nutrients in the leaveswas due to the time of year the leaves were collected. The lowestconcentrations of nitrogen, phosphorus, and potassium were foundin the leaves collected during the peak of the main season harvest.The highest levels of these elements were found in leaves collectednear the end or a few weeks after the end of the main harvest.The levels of calcium in the leaves were just opposite, withthe highest levels coinciding with harvest and the lowest levelsoccurring just after the harvest period. The levels of magnesiumshowed no marked variations between seasons. Shade increased the levels of nitrogen, phosphorus, and potassium,and decreased the levels of calcium in the leaves. Fertilizerincreased the levels of nitrogen, phosphorus, calcium, and magnesium,and decreased the level of potassium in the leaves. The effectof irrigation was small, but it decreased the levels of nitrogen,potassium, calcium, and magnesium in the leaves. The levels of nitrogen, phosphorus, and potassium in the leavesover the 21 harvesting times were found to be positively correlatedwith each other, and all three were negatively correlated withthe levels of calcium in the leaves over the same period. Noneof the levels of these four elements was significantly correlatedwith the levels of magnesium in the leaves over the period.     

Effects of silicon on the chemical composition of rice plants

Summary Rice plants were grown in nutrient culture solutions. Silicon was supplied to these plants at different rates. The plant samples of early vegetative, vegetative and flowering stages were analysed for nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, silicon, protein and carbohydrate contents. The application of silicon generally decreased the nitrogen, protein and potassium content of rice plants. Its application also decreased the iron and manganese contents. The use of silicon resulted in an increase in phosphorus, calcium, magnesium, silicon and carbohydrate contents of rice plants.Reader and Head of the Department of Soil Science, University of Dacca, Dacca, East Pakistan.     

The effect of nitrogen and phosphorus addition on the growth,reproduction, and nutrient dynamics of two ericaceous shrubs

Summary Aboveground growth, reproduction, and foliar nitrogen and phosphorus contents of two ericaceous shrub species were compared over two seasons in (a) an undisturbed shrub bog (pocosin), and (b) a factorial fertilization design in which three levels each of nitrogen and phosphorus were added in all possible combinations. One species, Zenobia pulverulenta, is deciduous whereas the other species, Lyonia lucida, is evergreen. In the nutrient-poor undisturbed pocosin the two species exhibited similar foliar nitrogen and phosphorus concentrations and aboveground growth rates. Neither species flowered. In response to nutrient-addition Zenobia increased growth rates more than Lyonia. Foliar phosphorus concentrations of both species increased in response to enhanced phosphorus availability. in the first season neither species flowered in any treatment. In the second season Zenobia flowered only in the fertilized plots, with the most flowering in the high phosphorus treatments. I conclude that, by virtue of high growth rates and efficient use of nutrients and despite differences in leaf phenology and morphology, both Lyonia and Zenobia are successful in a competitive community under conditions of extremely low phosphorus availability. However, unlike Lyonia, Zenobia can take advantage of temporarily increased nutrient availability, which occurs following fire in the pocosin, to increase growth and reproduction.     

Day and night temperature responses in Arabidopsis: effects on gibberellin and auxin content,cell size,morphology and flowering time

The effect of 16 different day (DT) and night (NT) temperature combinations (DT and NT 12, 17, 22 and 27 degrees C) on rosette leaf growth, flower stem elongation and flowering time in Arabidopsis thaliana Ler was investigated. Final leaf length decreased with increasing NT due to a combination of reduced elongation period and reduced elongation rate. Final stem length increased with increasing DT due to increased elongation rate, and decreased with increasing NT due to a decrease in elongation period. Under NT 27 degrees C, however, stem elongation rate increased greatly, resulting in the same final stem length as under NT 12 degrees C. The transition to flowering was accelerated by increasing NT. A linear regression analysis was performed to clarify the relationship between final leaf length, final stem length and flowering time with DIF (DT minus NT) and/or ADT (average daily temperature). For all three variables, the effect of DIF depended on ADT and vice versa. The relationship of final stem length with DIF also depended on the temperature range. Increased cell volume in flower stems developing at DT/NT 22/12 degrees C gave rise to longer and thicker stems compared with stems developing at DT/NT 12/22 degrees C. GC-MS analysis (gas chromatography-mass spectrometry) showed that the endogenous level of IAA was 56 % higher in stems grown under DT/NT 22/12 degrees C compared with DT/NT 12/22 degrees C. Of the 12 gibberellins analysed, however, only the level of non-bioactive GA29 was affected by the temperature treatment.     

Seasonal patterns of nutrient deposition in a Quercus douglasii woodland in central California

The monthly deposition of total nitrogen, phosphorus, potassium, calcium and magnesium via canopy throughfall, and various components of the litterfall was measured for 31 months under mature Quercus douglasii and in the bulk precipitation in the surrounding open grassland. Seasonal patterns of nutrient concentration in leaf litter, throughfall, and precipitation were also measured. Total annual subcanopy deposition exceeded open precipitation deposition by approximately 45–60x for nitrogen, 5–15x for phosphorus, 30–35x for potassium, 25–35x for calcium, and 5–10x for magnesium. Total annual subcanopy deposition was low in comparison to other oak woodland sites reported in the literature. Throughfall and leaf litter were the primary sources of nutrients and thus determined the seasonal peaks of nutrient deposition. The first autumn rains and leaf fall were associated with one peak in nutrient deposition, and throughfall during early spring leaf emergence was associated with a second peak in potassium, magnesium and phosphorus. Non-leaf plant litter (excluding acorns) provided approximately 15–35% of most nutrients, with twigs and bark depositing over 12% of the annual calcium flux in 1987–1988, and flower litter depositing over 8% of the annual nitrogen flux in 1986–1987. Acorns had high concentrations of phosphorus and nitrogen and during the mast season of 1987–1988 they contained a large proportion of the total subcanopy annual flux of these elements. With acorns excluded, total annual nutrient deposition was similar between years, but timing of nutrient deposition differed. Late summer leaf fall associated with drought, variation in precipitation, and variation in deposition of non-leaf parts were associated with seasonal differences in nutrient deposition between years.     

INFLUENCE OF SUPPLEMENTAL INORGANIC NUTRIENTS ON GROWTH,SURVIVORSHIP, AND MYCORRHIZAL RELATIONSHIPS OF SCHIZACHYRIUM SCOPARIUM (POACEAE) GROWN IN FUMIGATED AND UNFUMIGATED SOIL

Little bluestem grass Schizachyrium scoparium ([Michx.] Nash) plants were grown under field conditions for 2 years in soils fumigated with methyl bromide and chloropicrin, or in unfumigated soil, and treated with supplemental inorganic nutrients (bases calcium and magnesium) phosphorus, nitrogen, and potassium. Most differences in measured plant responses were due to interactions between fumigation and nutrient treatments. These included biomass production, root mass per unit length (μg/cm), root lengths, flowering culm production, percent colonization, colonized root length, and spore production in rhizosphere soil. Plants generally responded to mycorrhizal fungal colonization by reducing total root length and producing thicker roots. Treatment of plants with bases appeared to profoundly affect the mycorrhizal association by reducing sporulation of vesicular-arbuscular mycorrhizal fungi and increasing colonization. When fumigated or unfumigated soils were considered separately, base-treated plants produced more biomass than other treatments. Base-treated plants grown on unfumigated soil had more flowering culms and longer colonized root lengths than all other plants. Percent colonization by mycorrhizal fungi and colonized root length were positively correlated with phosphorus/nitrogen ratios, but the ratio was not correlated with plant biomass production. This suggests that phosphorus is not a limiting nutrient in our soil and investment in a mycorrhizal association may not result in enhanced plant growth. The base-nutrient effects may indicate a need to reevaluate earlier studies of macro nutrient effects that did not take into account the role played by calcium and magnesium in assessing fungus-host plant interactions.     

Effects of Nitrogen on the Development and Growth of the Potato Plant. 1. Leaf Appearance, Expansion Growth, Life Spans of Leaves and Stem Branching

Potatoes (Solanum tuberosum L) were planted in pots in a temperature-controlledglasshouse to collect data on the rate of leaf apearance, leafexpansion, apical lateral branching and active life spans ofleaves The treatments consisted of three rates of nitrogen supply,i e the NI treatment with 2 5 g N per pot and the N2 and N3treatments with 8 and 16 g N per pot, respectively The rate of leaf appearance was 0·53 leaves d^–1(one leaf per 28 °C d) and was negligibly affected by nitrogensupply The rate of leaf expansion was related to leaf numberand nitrogen supply The areas of mature leaves increased withleaf number on the main stem to reach a maximum for leaf numbers12–14, and declined for higher leaf numbers Leaves onapical lateral branches declined in mature area with increasein leaf number The expansion rate of leaves was the dominantfactor that determined the mature leaf area, irrespective ofleaf number and nitrogen treatment The smallest leaves wereobserved at the lowest rate of nitrogen supply Nitrogen promotedapical branching and hence the total number of leaves that appearedon a plant The proportion of total leaf area contributed byleaves on apical branches increased with time and nitrogen supply Active life span, i e the period of time between leaf appearanceand yellowing of the leaf, showed a similar relation to leafnumber as mature leaf area, at least in qualitative terms Leavesof the N3 treatment showed systematically longer life spansthan leaves of the NI and N2 treatment in the order of 3 weeksThe number of main stem leaves was not affected by nitrogensupply Potato, Solanum tuberosum L, leaf development, leaf extension, plant structure, nitrogen nutrition     

The Relation between the Putrescine Content and Potassium Status of Black Currant Leaves

Black currant cuttings were grown with six levels of potassiumand two levels of phosphorus. Shoot length, leaf number, leafweight, and deficiency symptoms were recorded 11 and 16 weeksafter commencement of the treatments, and leaf samples wereanalysed for putrescine, potassium, and nitrogen. Shoot length,leaf number and leaf weight were reduced by potassium deficiency,the greatest effect being observed in leaf weight Potassium-deficiencysymptoms appeared first on the lower branches, the most severedeficiency symptoms being found on the plants grown with highphosphate. In terms of the fresh weights, the highest concentrationof both putrescine and potassium were found in the leaves ofthe upper shoots. Lower putrescine and higher potassium levelsin the leaves were found in the low-phosphate nutrient series.In terms of cation equivalents the deficit of potassium wascompensated to the extent of 30 per cent by the formation ofputrescine.