共查询到20条相似文献，搜索用时 31 毫秒
1.
G. C. Head 《The Journal of Horticultural Science and Biotechnology》2013,88(2):169-180
Measurement of the white root, visible through glass panels, from young apple and plum trees showed that production of new white root was reduced during periods of intense shoot growth. On the apple trees maximum quantities of white root occurred in May, at about the time of full bloom, and again in August or September after shoot growth had ceased. In contrast, on some of the plum trees with only a few weak shoots, maximum white root was recorded in June and only small amounts of new white root were present during the remainder of the year. The effect of branch pruning was to stimulate more intense shoot growth: the more intense the shoot growth the greater and more prolonged was the reduction in new white root production in mid-summer. The interpretation of these results in terms of the physiological relationship between root and shoot is discussed. 相似文献
2.
D. G. Hill-Cottingham R. R. Williams 《The Journal of Horticultural Science and Biotechnology》2013,88(4):319-338
Fertilizer nitrogen was applied to pot-grown trees during the year of initial scion growth either as “spring N”, “summer N” or “autumn N”, while other trees were left untreated—“minus N”. Tree performance was followed until fruit set the following summer.At regular intervals whole trees were sampled, divided into as many as seven different parts, which were separately weighed, dried and analysed for total nitrogen. Specimens were also taken for histological examination of flower bud development.The large amount of fertilizer given as “spring N” resulted in extensive root damage from which the trees did not recover fully; nevertheless they produced large, vigorous scions. After “spring N” and “summer N” at lower dosages the total N content of all parts increased substantially and rapidly. “Autumn N” was absorbed more slowly and remained largely in the roots during the winter, when a considerable amount of root growth took place.Flowers were initiated in late July or early August on all trees except those given “spring N”, on which flower primordia were not initiated until September. The development of flower buds was accelerated during September on “summer N” trees compared with those left untreated. From the end of November until the end of March no further differentiation took place on “minus N” or “spring N” trees, but it continued on the other treatments, especially following “autumn N”.“Summer N” and “autumn N” trees were 4–5 days in advance of the others in flowering. “Summer N” trees had large flowers and large green primary leaves, whereas those on “autumn N” trees were smaller and the leaves were initially pale, though turning dark green during blossoming.When the blossoms were self-pollinated under controlled conditions virtually no fruit was set on “minus N” and “spring N” trees, but “summer N” gave an appreciable set and “autumn N” a heavy set. Only the “summer N” and ”autumn N” flowers had ovules that remained viable six days after anthesis, which was the minimum period found necessary for the pollen tubes to effect fertilization.It is suggested that fertilizer nitrogen stimulates the synthesis of a kinin-like factor in the roots and that the difference in response to applications at different times of year depends upon the stage of development of the flower buds when this factor reaches them. 相似文献
3.
G. Bi C. F. Scagel L. Cheng S. Dong L. H. Fuchigami 《The Journal of Horticultural Science and Biotechnology》2013,88(6):853-858
SummaryJune-budded ‘Nonpareil’/‘Nemaguard’ almond (Prunus dulcis (Mill) D. A. Webb) trees were fertigated with one of five nitrogen (N) concentrations (0, 5, 10, 15, or 20 mM) from July to September. The trees were sprayed with either water or 3% urea in October, then harvested bareroot after natural leaf fall, and stored at 2°C. One set of trees was destructively sampled for total N content; the remaining trees were transplanted into N-free media in the spring after cold storage. After budbreak, these trees were supplied for 70.d with either N-free Hoagland’s solution or Hoagland’s solution containing 15N-NH4NO3. Nitrogen concentrations in both stem and root tissues were positively correlated with the N-fertigation concentration. Fall foliar urea applications increased levels of stem and root N regardless of the N-fertigation concentration. During the first 70 d of spring growth, the trees utilized nitrogen from both their reserves and spring fertilizer applications. The amount of N reserves used for growth of new shoots and leaves was proportional to the total amount of reserves. Trees with low N reserves relied primarily on the spring fertilizer as their source of nitrogen. We conclude, therefore, that both reserve N and spring-applied N fertilizers are important for enhancing the regrowth of bareroot almond nursery trees during establishment after transplanting. Nitrogen fertilization in the spring can especially improve the performance of trees with low N reserves. 相似文献
4.
蚯蚓对苹果园土壤生物学特性及幼树生长的影响 总被引：2，自引：0，他引：2
以果园褐土、潮土和棕壤以及2年生红富士苹果(Malus domestica Borkh. ) 幼树为试材, 在盆栽条件下, 通过向盆土埋放蚯蚓, 研究蚯蚓对土壤酶、土壤微生物量碳和氮以及苹果根系和新梢生长的影响。结果表明, 引入蚯蚓后, 3类土壤中脲酶、酸性磷酸酶和碱性磷酸酶活性以及微生物量氮均显著提高, 其中棕壤脲酶活性提高78.9% , 潮土碱性磷酸酶活性提高170.0% , 棕壤微生物量氮提高180.4%。蚯蚓处理也显著提高褐土和潮土微生物量碳, 其中潮土微生物量碳提高幅度最大, 达299.2%。3类土壤经蚯蚓处理后, 苹果幼树根系活力、根系和新梢生长量均显著提高, 其中, 棕壤中的幼树根系活力最高, 褐土中的幼树根系生长量最大, 潮土中的幼树新梢生长量最大。 相似文献
5.
G. C. Head 《The Journal of Horticultural Science and Biotechnology》2013,88(2):197-206
A method of estimating the length of root visible in observation windows by counting the intersections between roots and the lines of a half-inch grid, marked on the glass, is described. Seasonal changes in the amounts of white, unsuberized root present varied between different kinds of apple trees growing in the same environmental and soil conditions. The cortex of apple roots often took three months to turn brown in the winter but this interval had decreased to an average of 2-3 weeks by May and remained fairly constant at this level until the end of September. Fluctuations in the quantities of white root present during the summer thus gave a fair indication of fluctuations in the production and growth of new roots. 相似文献
6.
In a study on the growth and cropping of strawberries under contrasting soil nitrogen conditions in a trial extending over six years, annual split applications of Nitrochalk maintained distinct regimes of mineral nitrogen in the soil but 30 tons/acre F.Y.M., prior to planting, had little additional effect. Nitrogen deficiency was achieved by preplanting applications of straw but this only lasted for one season.There was a regular pattern in leaf nitrogen concentration associated with the different phases of strawberry growth. The concentration showed a linear response to increments of fertilizer nitrogen. Leaf colour gave visual evidence of these differences.F.Y.M. did not affect plant growth or cropping but nitrogen applications resulted in small increases in both plant spread and number of crowns per plant.Nitrogen at 200 lb. N/acre depressed the yields of marketable fruit in each of the four years. This was due only in part to an increase in wastage and it is suggested that a high nitrogen status in the plant could reduce the number of fruits per truss. The lower rate (50 lb. N/acre) gave yields generally similar to the nil control.Nitrogen levels had little influence on the intensity of flowering in spring, whereas autumn flowering decreased sharply as nitrogen levels increased. Floral initiation thus appears much more sensitive to the nitrogen status of the plant in July than in September. 相似文献
7.
G.C. White D. W. P. Greenham 《The Journal of Horticultural Science and Biotechnology》2013,88(4):419-428
The seasonal levels of ammonium and nitrate nitrogen were determined, over 3 years, within the top 24 inches of soil of a long-term NPK trial on dessert apples. The four treatments selected provided comparisons of cultivated and grassed plots receiving spring applications of Nitrochalk with those having received no nitrogen since 1930. The three seasons included a very dry one in 1959 and the unusually wet summer of 1960.Ammonium nitrogen did not persist as such for long periods, and nitrate nitrogen was the major form of mineral nitrogen.There was a marked contrast between the levels under the two management systems. Grass maintained a low level throughout most of the season, whereas a steady rise in nitrate nitrogen took place until July or later in the cultivated soil; thereafter, the level fell in response to rainfall. By mid-winter, very little nitrate nitrogen remained in the 24-inch profile.Applications of nitrogenous fertilizer did not markedly affect the mineral nitrogen status in the grassed plots but, in the cultivated soil, levels substantially exceeding the annual applications were found. These seasonal trends are discussed in relation to the processes involved in the cycling of mineral nitrogen.Estimates of the annual amounts mineralized in the cultivated soil receiving no added nitrogen suggest that even after 30 years this amount may be of the same order as the net uptake by the trees, thus explaining their apparently satisfactory nitrogen status.In the grassed plots, the rapid re-cycling of nitrogen from the clippings may be an important factor in maintaining an adequate supply to the tree. 相似文献
8.
9.
Moreno Toselli Elena BaldiGiovambattista Sorrenti Maurizio QuartieriBruno Marangoni 《Scientia Horticulturae》2010
We assessed the effect of soil-applied derivatives of melia (Melia azedarach L.) and neem (Azadirachta indica A. Juss) on nitrogen (N) soil availability, root uptake and peach (Prunus persica L.) growth. First we evaluated the effectiveness of experimentally prepared amendments made with fresh ground melia leaves or commercial neem cake incorporated into the soil as nitrification inhibitors, then we evaluated the effect of fresh ground melia fruits and neem cake on growth and N root uptake of potted peach trees, and on soil microbial respiration. Soil-applied fresh ground melia leaves at 10 and 20 g kg−1 of soil as well as commercial neem cake (10 g kg−1) were ineffective in decreasing the level of mineral N after soil application of urea-N as a source of mineral N, rather they increased soil concentration of nitric N and ammonium N. The incorporation into the soil of fresh ground melia fruits (at 20 and 40 g kg−1) and neem cake (at 10 and 20 g kg−1) increased N concentration in leaves of GF677 peach × almond (Prunus amygdalus) hybrid rootstock alone or grafted with one-year-old variety Rome Star peach trees. An increase in microbial respiration, leaf green color and plant biomass compared to the control trees were also observed. The Meliaceae derivatives did not affect, in the short term (7 days), N root uptake efficiency, as demonstrated by the use of stable isotope 15N, rather they promoted in the long term an increase of soil N availability, N leaf concentration and plant growth. 相似文献
10.
果梅幼树对春施~(15)N-硫铵的吸收与分配 总被引：5，自引：0，他引：5
以盆栽3年生细叶青梅/毛桃为试材,研究了早春施用~(15)N-(NH_4)_2SO_4条件下,果梅对~(15)N的吸收分配规律。结果表明:由于春季土温较低,限制了植株对肥料氮的利用率。在新梢旺长期,植株从肥料氮中吸收的氮素营养主要用于新生器官的建造,且新梢成为~(15)N的主要分配中心,其次即为果实,再其次为细根。至花芽分化期,植株的生长中心已发生转移和分散,但春施氮对促进当年生枝的花芽分化和维持叶片正常光合功能仍有重要作用,此期亦是根系生长的关键时期之一,且与贮氮相比,春施氮更有利于当年新根的萌发和根系的扩大。 相似文献
11.
分期施肥对富士苹果钙素吸收的影响 总被引：2，自引：0，他引：2
为了确定苹果钙的吸收利用与施肥时期的关系,以盛果期的富士苹果(Malus domestica cv.Fuji)为试材,比较了相同钙素含量分期施肥的效果,结果表明,春季一次性施肥能够大幅度提高当季土壤总钙和交换性钙、根系及幼果的钙浓度,但后期下降显著;春夏2次施肥能极显著提高夏季根系钙浓度,促进膨大期的果实吸收和积累大量的钙;分3次施肥能保持整个生长季节土壤和根系钙素供应水平的稳定,成熟果实钙的浓度和积累量明显高于其它施肥处理。研究结果进一步证实,幼果期能够吸收积累成熟果实46.8%～62.4%的钙,膨大期的果实能够继续吸收积累约总钙的33.85%～45.42%,即使是秋季,如果施肥也能积累较高比例的钙(占总钙量的13%～18.6%)。长期、适量的连续补充钙肥有利于改善果实的钙素营养。 相似文献
12.
D. Stephens 《The Journal of Horticultural Science and Biotechnology》2013,88(1):75-90
In about 70 trials on small African Robusta coffee farms and 100 similar trials on small Arabica farms mean responses to nitrogen fertilizers were profitable and became increasingly so with continued applications. A soil treatment with magnesia in 21 Robusta trials gave no increase in yield when applied in addition to the nitrogen fertilizer. The other Robusta trials compared urea with ammonium sulphate and showed that there was no significant difference in their effects on yields. The ratio of dried to fresh cherry weight was not decreased by the nitrogen fertilizer.Over 100 correlations of yields or responses with agronomic details and soil and leaf analyses were tested for significance. Routine soil analyses proved disappointing indicators of coffee yield or response to nitrogen, which confirms other evidence that nitrogen is the only major deficiency in Ugandan coffee. Agronomic practices seemed to have only minor effects on yield. Leaf nutrient contents were often significantly correlated with yields, but none with sufficient regularity to indicate a real and common association. Correlations between leaf nitrogen and yield were never significant even though the treatments significantly affected the levels of leaf nutrients. This is contrary to the results in earlier station experiments. 相似文献
13.
2014—2016年,以‘黄冠’梨为材料,采用15N示踪技术研究了从幼树期到结果初期梨树对春季施用氮素的吸收利用及土壤残留与损失情况。研究结果表明,幼树期(2014—2015年)梨树生长以中心干和粗根等树体骨干结构建立为主,生长量相对较小;进入结果初期(2016年)后树体生长表现为树体骨干结构建立为主,枝梢等营养器官生长与产量形成并存,生长量大幅增加。整个试验期间,树体贮藏器官的标记氮素吸收量较大,其中幼树期中心干吸收量最大,结果初期粗根吸收量最大。0~100 cm土层标记氮素残留量随土层深度和施用年限增加逐渐降低,其中,施用标记氮素后第1年(2014年),土壤标记氮素残留量较高,残留率达63.61%,梨幼树对标记氮素利用率仅为3.25%。随后两年(2015—2016年)土壤残留量较低,树体对标记氮素利用率仅为0.51%和0.80%。试验结束时,幼树期到结果初期梨树对标记氮素的累计利用率为4.57%,土壤标记氮素残留量为20.34%,损失率达75.07%。 相似文献
14.
15.
Soil aeration is an important factor in tree growth. Oxygen must be taken from the atmosphere for root respiration, and carbon dioxide must be discharged to the atmosphere. Because the pore space of the soil could be considered the “dead end” of the free atmosphere, topsoil gas diffusivity is particularly important for soil aeration. Due to diverse land uses, several soil cover types alternate on a small scale at urban sites, competing with the natural function of soil as the living space for roots.During Documenta 7 in 1982, the artist Joseph Beuys initiated the spectacular landscape art project “7000 Oaks”. Seven thousand trees of approximately the same age were planted over the whole city of Kassel, Germany, offering best possible conditions for investigating the influence of specific site factors on root and tree development. At 8 different sites featuring 36 Beuys-oaks and 15 Beuys-planes, topsoil gas diffusivity, soil CO2 concentration and soil respiration of different soil cover types were measured and correlated with fine root density and tree growth.Topsoil gas diffusivity and soil respiration depend on soil cover type. The lowest gas diffusivities and respiration rates were found at sealed sites, and the highest values were measured at vegetated sites such as lawn or flower beds. Soil gas diffusivity primarily controls soil respiration. Soil CO2 concentration is not strictly linked to the coverage type and does not show a strictly directed dependence on top soil gas diffusivity and soil respiration. Tree root density and height as well as diameter at breast height (1.3 m) of the oaks were decisively shaped by the gas diffusivity of the soil cover, whereas the investigated planes were not affected by soil aeration deficiencies. The vitality of urban trees can be controlled by the design of the tree site and the choice of the species. 相似文献
16.
Nitrogen fertilization during planting and establishment of the urban forest: A collection of five studies 总被引：1，自引：0，他引：1
Today's urban forest increasingly consists of planted trees, especially as native forest fragments yield to urban sprawl. These trees are usually larger (over 2-m tall) than typical reforestation trees and grow very little for the first few years after planting. Stressful urban sites exacerbate this effect and many practitioners hope to shorten the time required to reach environmentally functional size by fertilizing at planting. This is a controversial practice since nitrogen (N) application creates the potential for water quality impairment and effectiveness is uncertain. It is not clear how nitrogen application affects large trees with radically altered root:shoot ratios or how nursery production methods and restrictive sites affect response. In a series of five separate studies, we tested several N rates on ten shade tree species (both field- and container-grown) and transplanted to a range of urban sites, from a relatively undisturbed forest fragment to a highly compacted cutover soil with an absent A horizon. Trunk diameter increase, as an integrative metric of tree biomass accumulation, was followed for up to 4 years on each experiment. Overall, we saw little effect from fertilizing at planting at any rate we tested, regardless of location. Three studies that included leaf analysis with a SPAD-502 chlorophyll meter indicated that neither SPAD meter values or N concentration within leaves was increased by fertilizing at planting, suggesting that the newly planted shade trees took up very little of the applied N. Overall, SPAD-502 readings correlated well with actual leaf N concentration (r=0.692). This group of studies indicates that fertilization at planting does not increase post-transplant growth, even in stressful urban sites and it is therefore not effective at shortening the establishment period of transplanted shade trees. 相似文献
17.
The root extension rate of Betula pendula, transplanted at two phenological stages, was studied in a Nordic climate. Landscape-size trees were transplanted from the field into root-study boxes (rhizotron) in early and late spring of 1999 and 2000. In early spring, 6 trees were transplanted when the leaves had just started to unfold; likewise, in late spring, six trees were transplanted when the leaves were fully unfolded and the shoot extension was in progress. Root growth was recorded during the first post-transplant season and the tree roots were finally excavated. Results indicate that the root extension rate of B. pendula follows seasonal soil temperature. The mean root extension rates at ten days intervals varied from 4 to 11 mm/day with a total average for the growing season of 7 mm/day in 1999 and varied from 4 to 9 mm/day with a total average for the growing season of 4 mm/day for 2000. The average length of new roots was 89 cm and there was no significant difference in length, dry weight or number of new roots between the two transplant times. It appears, therefore, that the phenological stage at transplanting during the period from bud break to fully developed leaves has minor effect on landscape establishment of B. pendula, when an adequate amount of water is provided. 相似文献
18.
Plastic film mulches are often associated with increases in plant growth and yield of vegetable crops. Few studies, however, report on the effect of plastic film mulches on root zone temperature on broccoli. The objectives of this study were to determine the effects of colored plastic mulches on root zone temperature and broccoli plant growth and yield Broccoli (‘Packman’) plants were grown using plastic film mulch and drip irrigation. The treatments consisted of plastic film mulch (black, blue, gray on black, red, silver on black, and white on black mulches) and bare soil. Colored plastic film mulches affected root zone temperature and the accumulation of soil degree-days. Mean daily RZT, maximal daily RZT and degree day accumulation in the soil were highest in dark-colored mulches (blue, black, red, and gray) and lowest in light-colored mulches (silver and white), while minimal daily RZT was highest in silver mulch and lowest in white mulch. Silver mulch showed the smallest diurnal fluctuations in RZT among plastic mulches, with the highest RZT during the night and among the lowest in the afternoon. Colored plastic mulches also affected broccoli plant growth and yield, although the effect of mulches was more dramatic in the spring than in the fall seasons. Broccoli yield was linearly related to both the vegetative top dry weight and root dry weight of mature plants. Broccoli yield was little affected at mean RZT of <21 °C but increased with increasing mean RZTs above 21 °C up to 25 °C. Thus, broccoli plant growth and yield responded more favorably to dark-colored mulches than to light-colored mulches, suggesting that broccoli benefited from increased soil warming. No high RZT stress effects on broccoli plant growth or yield were observed in this study. Thus, this study suggests that plastic film mulches, particularly the dark-colored mulches, may be an option for spring broccoli production in areas with cool conditions early in the spring. 相似文献
19.
SummarySeeds of Fagus sylvatica, Prunus avium and Acer pseudoplatanus were sown on 10 May and covered with four materials: white polyethylene, white polypropylene, yellow net or green net for 90 d to study the effect of a temporary covering on soil and air temperature, increment in dry weight, and root cellular diameter of nursery tree seedlings in a northern climate. Root collar diameter, height and dry weight of covered seedlings were compared with those of uncovered control seedlings at the end of growing season. The increase in soil and air temperature under white polyethylene, white polypropylene and yellow net and the decrease in soil temperature under the green net influenced the growth of F. sylvatica and P. avium seedlings. Dry weight, as well as root collar diameter and height, was increased under the coverings increasing temperature. A. pseudoplatanus responded less to temperature, but increased dry weight and root collar diameter when cultivated under white polypropylene and green net. Hence temporary coverings can be used to improve the quality of seedlings grown in a northern climate. 相似文献