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SummaryEffects of organic and inorganic nitrogen fertilizers and soil moisture content were determined on the emergence of lettuce seedlings in controlled environment conditions. The effect of various nitrogen fertilizers and potassium chloride were also studied on emergence of lettuce and carrot seedlings in the field. Seedling emergence declined with increasing rate of applied nitrogen fertilizer, irrespective of the form supplied. However, fewer seedlings emerged with ammonium nitrate under dry soil conditions compared with organic sources, whereas the opposite was true in soil with a high moisture content. There was little effect of applied potassium chloride on seedling emergence. Factors affecting emergence of seedlings in soil amended with organic and inorganic N fertilizers are discussed. 相似文献
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The use of pre-germinated seeds for establishing glasshouse lettuce in peat blocks was compared with dry and pelleted seeds. Sowing pre-germinated seeds gave between 1 and 6% higher seedling emergence than from pelleted seeds and between 1 and 3% higher emergence than from dry seeds. Seedling emergence was reduced from 100% to 56% when the seeds were covered with 5 mm of silver sand compared with no cover. Seedling emergence from seeds covered with Agrigel (sodium alginate) was reduced by 24% at a concentration of 0.25% and by 62% at 0.7% compared with no cover.Guar (a natural gum) and Laponite (a synthetic clay) gels also reduced emergence on certain occasions but not by as much as Agrigel. Satisfactory levels of emergence were obtained when seeds were sown into blocks having an inverted, cone-shaped depression for locating the seeds, but the seedlings showed poor root-hair development and had elongated hypocotyls. Normal seedling growth and high levels of emergence were obtained from the seeds sown into blocks having cylindrical holes 10 mm in depth and 5 or 10 mm in diameter. Pre-germinated seeds invariably emerged earlier than pelleted or dry seeds. At low propagating-temperatures (12.0°C maximum and 5.0°C minimum), emergence was 4 days earlier from pre-germinated than from dry or pelleted seeds and 2–3 days earlier at high temperatures (21.0°C maximum and 9.0°C minimum). Coefficients of variation of seedling weight at planting were lower from sowing pre-germinated than pelleted or dry seeds, but these differences were not evident at harvest. 相似文献
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Sowing pre-germinated seeds with radicles 2–3 mm long reduced the time from sowing to seedling emergence to 17 days compared with 41 days in untreated seeds at soil temperatures of 10°C, and to 5 days compared with 11 days at 18°C. Sowing pre-germinated seeds also improved percentage seedling emergence and reduced the variability of times of emergence of individual seedlings. Seeds imbibed for 56 h before sowing (radicles just emerging) emerged about 3 days earlier at both 10°C and 18°C than untreated seeds. Seeds soaked in a solution containing 1.5% each of KNO3 and K3PO4 for 5 days at 24°C, or in “Carbowax 20 M” for 20 days at 15°C, and then dried before sowing, gave results similar to imbibed seeds. Soaking seeds in 70% of their weight of water followed by drying for different lengths of time and for different numbers of cycles of wetting and drying did not improve germination or seedling emergence. 相似文献
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《Scientia Horticulturae》1986,29(3):239-249
The response of passionfruit hybrids (Passiflora edulis f. edulis × P. edulis f. flavicarpa cultivar E-23 on P. edulis f. flavicarpa seedling rootstocks) to soil moisture was evaluated in a heated glasshouse by irrigating when soil water pressure potential fell to −0.0025, −0.01, −0.14 and −1.5 MPa. Leaf, stem and root dry weight, leaf area, vine extension and node, flower bud and open flower number were reduced by soil moisture stress. Changes were also noted in a range of morphological characteristics. Reductions in growth and flowering were associated with reduced nutrient uptake and leaf water potential, but not leaf conductance. It was concluded that moisture stress may be one of the major environmental factors responsible for seasonal fluctuations in passionfruit yields. 相似文献
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以"金棚8号"番茄为试材,采用基质栽培法,普通自来水配制的营养液(CK)为对照,研究了有效氯浓度分别为20 mg·L^-1(SAEW20)、40 mg·L^-1(SAEW40)、60 mg·L^-1(SAEW60)、80 mg·L^-1(SAEW80)的微酸性电解水配制的营养液对番茄幼苗生长和光合作用的影响,以期验证微酸性电解水作为一种功能水对番茄幼苗生长是否具有促进效应。结果表明:SAEW80处理下的番茄幼苗干鲜质量均显著高于对照;SAEW80处理能显著增加番茄幼苗叶面积,且提高壮苗指数的效果显著;微酸性电解水的有效氯浓度对番茄幼苗叶片中叶绿素和类胡萝卜素的影响较小;根施微酸性电解水可以提高番茄幼苗的净光合速率和水分利用效率;SAEW80处理下的番茄幼苗根系总表面积、总体积和平均直径最高且显著高于对照。总之,低有效氯浓度的微酸性电解水配制营养液对番茄幼苗根施不会影响植株的正常生长,而高有效氯浓度在一定程度上可以促进番茄幼苗的生长,可以使用高有效氯浓度(80 mg·L^-1)微酸性电解水进一步研究作用机理。 相似文献
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P. J. M. Sale D. J. Harrison 《The Journal of Horticultural Science and Biotechnology》2013,88(3):147-161
The effect of irrigating a seedbed after sowing has been compared with the effect of irrigating before the final cultivation and sowing. The total numbers emerged and rate of emergence of lettuce, spinach and beet were reduced if the soil surface was capped by post-sowing irrigation and the cap then dried out; a wet cap did not affect emergence. On the other hand, post-sowing irrigation with small drops, which caused little or no soil capping, tended to increase seedling emergence compared with presowing irrigation when the sowing depth was \ in. or i in. Moreover, when lettuce were sown at \ in. depth pre-sowing irrigation gave poor emergence because of rapid drying of the soil round the seed before it could germinate ; post-sowing irrigation with small drops again resulted in good emergence, however, as did post-sowing irrigation with large drops if the resulting cap was broken by light cultivation as soon as it dried. 相似文献
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P. I. Orphanos 《The Journal of Horticultural Science and Biotechnology》2013,88(3):447-455
The failure of Phaseolus vulgaris seedlings to emerge when irrigated after seeding was found to be caused mainly by mechanical impedance of the wet soil and not by soaking injury. Seeds sown deeper than 2-5 cm and then irrigated produced abnormal seedlings with thickened, flattened and hollow hypocotyls. In addition, such seedlings often sustained damage such as the loss of a cotyledon or the breaking of the hypocotyl. Seeds soaked in 1% hydrogen peroxide, which is known to prevent soaking injury and to promote seedling growth in germination boxes, emerged poorly in soil, presumably due to bruising of the water-saturated cotyledons while pushing through the soil. Satisfactory emergence can be obtained, however, from seeds sown 2-5 cm deep and then irrigated provided the soil is not allowed excessively either to dry out or become heated by solar radiation. 相似文献
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温度和光周期对苦瓜性别表现的影响 总被引:7,自引:0,他引:7
苦瓜苗期所处的环境条件会影响其性别表现,株洲长白和英引苦瓜品种的光周期反应表现为短日效应,即短日使植株的发育提早,并促进雌性发育,长日的效果恰好相反。苦瓜苗期短日处理时期以出苗至6片真叶(苗龄20天)为宜。低温可以增强短日效应,高温则使苦瓜的生殖生长推迟,并削弱短日效应,短日低温是苦瓜苗期最适宜的环境条件。 相似文献
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T. W. Hegarty 《The Journal of Horticultural Science and Biotechnology》2013,88(1):133-146
Calabrese, carrot, onion and red beet seeds were sown at approximately weekly intervals throughout the spring and early summer of 1972–4. In a situation where soil tilth and seed placement in the soil were apparently non-limiting, regression analysis showed that in eight of the twelve crop × year combinations there were no significant relationships between seedling emergence and soil moisture or temperature at sowing. In 1972 emergence levels of beet and calabrese were depressed by either excess or lack of soil moisture at sowing, and calabrese emergence was positively related to temperature; in 1973 and 1974 onion emergence was negatively related to temperature at sowing. Rainfall occurring shortly after sowing was identified as a major factor causing emergence problems, apparently through the formation of a soil cap, but its effect varied with crop type, seed vigour and soil moisture content at the time of seedling emergence. The results suggest that low plant stands often found in agricultural practice may be due not to soil temperature or moisture, factors dependent largely upon the weather, but to soil tilth, fertilizer level, seed or soil infection, seed drill performance and seed vigour, over all of which except the last there is, theoretically, some control. 相似文献
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Idowu Babadele Famuwagun Samuel O Agele O.Peter Aiyelari 《International Journal of Fruit Science》2018,18(2):153-176
ABSTRACTThe deployment of plantain shade and irrigation (5- and 10-day) intervals) for enhancing survival, field establishment, flowering and pod production of field-grown cacao seedlings in the dry season was investigated. The effects of dry season irrigation was profound on cacao growth, field establishment (over 90% seedling survival) and development, flowering and pod production. For the non-irrigated moderately shaded cacao, about 30% of the transplanted seedlings survived and the achievable percent survival from the various shade-irrigation combinations ranged from 47–90%. Open sun in combination with 5-day irrigation interval had best results in term of growth (root and shoot development and biomass accumulation) and establishment, flowering and pod production. Lower values of air and soil temperatures were obtained for combination of irrigation and shade regimes (dense and moderate) and higher soil moisture contents. The shade-irrigation combinations ameliorated microclimate and enhanced growth and development, seedling survival, root and shoot development, advanced flowering and promoted uniform fruiting/pod production and total bean yield. The effects of dry season irrigation at 5- or 10-day intervals was profound on cacao growth, field establishment (over 90% seedling survival), flowering and pod production. Irrigated unshaded (open sun) cacao had best results in term of growth (root and shoot development and biomass accumulation) and establishment, flowering and pod production. The achievable percent survival from the various shade-irrigation combinations ranged from 47–90%. The drip irrigation strategy adopted ameliorated dry season terminal drought (hydrothermal stresses) and promoted cacao growth, survival and flower/pod production. 相似文献