Weed competition in cauliflower (Brassica oleracea L. var. botrytis) in the Jordan Valley

A field experiment was carried out in 1996/1997 and repeated in 1997/1998 at the Jordan University Research Station located in the central Jordan Valley to determine the effect of weed competition on growth and yield of cauliflower Brassica oleracea var. botrytis cv. “White Cloud”. The treatments consisted of either allowing weeds to infest the crop or maintaining plots weed-free for increasing durations after transplanting. Results showed that longer periods of weed/cauliflower competition greatly reduced crop growth and head yield. Average reductions in shoot dry weight and head yield were 81% and 89%, respectively. Maintaining a weed-free crop for any period after transplanting increased cauliflower growth and head yield compared with the weed-infested control. Weed competition for 14 days after transplanting reduced cauliflower average head yield by 41%. To determine the critical period of weed competition and the influence of weed infestation on cauliflower head yield the Gompertz and logistic equations were fitted to data representing increasing duration of weed-free and weed-infested periods, respectively. Based upon an arbitrary 5% level of head yield loss, the critical period of weed competition occurred at 0–38 days after cauliflower transplanting which corresponded with the rapid increase in weed biomass. Results indicated that early weed removal is necessary to prevent yield loss.     

不同肥料处理对青花菜产量和品质的影响

研究了不同施肥处理对青花菜产量与主要品质指标的影响,试验结果表明,生物有机肥能提高青花菜的产量和品质,效果以酵素菌生物有机肥和复合微生物肥复配最显著,有机肥对产量和品质无显著影响。2种生物有机肥复配使青花菜产量提高20.78%,抗坏血酸、可溶性蛋白、可溶性糖、干物质含量分别提高34.2%、46.0%、43.8%、6.13%。     

Study of some factors affecting the growth and development of myoga (Zingiber mioga Roscoe)

In order to optimise production of the edible flower buds produced by myoga (Zingiber mioga Roscoe) a greater understanding of the growth and development of the plant and factors influencing flower initiation and development are required. The vegetative growth phase in myoga was characterised by a distinct period of pseudostem development from the planted rhizome piece followed by an extended period of rhizome growth from both the base of pseudostems and the planted rhizome piece. The transition from pseudostem formation to the initiation of rhizome growth occurred at the same time as the dry weight of the planted rhizome piece ceased to decline. Flower bud initiation and development occurred over an extended period, beginning soon after the commencement of new rhizome growth and ending prior to foliage senescence. Flower buds were observed at the terminal meristem of first, second, third and fourth order rhizomes. Increasing temperatures stimulated both increased vegetative growth and flower bud initiation and development. Low flower bud yields recorded under conditions of low temperature were the result of reduced rate of floral initiation and not abortion of flower buds. Increased shading of plants grown under glasshouse conditions resulted in reduced flower bud yield and similarly the response resulted from decreased initiation rather than abortion.     

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 conventional and organic fertilization on spinach (Spinacea oleracea L.) growth,yield, vitamin C and nitrate concentration during two successive seasons

Current experiment was laid out in order to compare different kinds of organic manure and chemical fertilizer application in growing spinach under the open-field conditions in two successive seasons. Matador type spinach (Spinacea oleracea L.) was cultivated organically and conventionally and spinach growth, yield, vitamin C and nitrate concentrations were checked throughout two successive seasons (autumn and winter). Commercial chemical fertilizer was used as conventional application, and chicken manure (CM), farmyard manure (FM) and blood meal (BM) were used as organic manure applications as a single and as mixtures at different quantities by aiming to receive 150 kg N ha⁻¹ for each, totally 19 applications. In general, autumn season gave the better results in terms of spinach growth, yield and resulted in lower nitrate concentration, whereas the vitamin C concentration was found to be higher in winter season. Reasonable applications to be recommended should be as follows with regard to the seasons; 3.5 ton ha⁻¹ CM and 0.6 ton ha⁻¹ BM + 0.85 ton ha⁻¹ CM + 4.0 ton ha⁻¹ FM for spinach growth; 3.5 ton ha⁻¹ CM and 5.0 FM + 1.2 CM + 0.4 BM applications for spinach yield; 5.0 ton ha⁻¹ FM + 2.5 ton ha⁻¹ CM and 15.0 ton ha⁻¹ FM for vitamin C and nitrate concentration in the autumn and the winter season, respectively. In conclusion, FM and CM can be used effectively in growing organic spinach especially in the autumn season and can be transferred successfully into an asset.     

Effect of light,temperature and CO2 on the growth of Campanula isophylla stock plants and on the subsequent growth and development of their cuttings

Stock plants of Campanula isophylla Moretti were subjected to different temperature and light conditions and to various CO₂ regimes. The number and the fresh and dry weight of the cuttings produced were recorded. The after-effect of stock-plant treatment on root formation and growth of cuttings was studied.Increasing light intensity and CO₂ supply strongly promoted cutting production and increased both fresh and dry weight of the cuttings. These factors also markedly influenced root formation and root growth of the cuttings. Stock plant conditions also strongly influenced the growth and lateral shoot formation of the rooted cuttings. It is concluded that cuttings from stock plants grown under favourable light (10 Klx) and CO₂ conditions (900 v.p.m.) contain factors beneficial for root formation, growth and shoot formation. The results are discussed in relation to the carbohydrate content of the cuttings.     

青花菜小孢子胚植株再生及倍性研究

以庆农70和庆农80为试材对青花菜小孢子胚状体植株再生因素进行研究。结果表明:胚龄为30～35d且发育健壮的子叶形胚再生成苗率最高,超过75%,胚龄超过40d再生成苗率显著降低;琼脂浓度为1.2%时,小孢子胚再生成苗率最高,达60%～70%;大多小孢子胚不能直接成苗,二次分化频率较高;植株继代和复壮培养适宜培养基为MS+3%蔗糖+1.0%琼脂;小孢子再生植株一半左右为单倍体,二倍体率为30%～35%,存在少数四倍体和嵌合体。     

Effects of elevated CO2 on growth and morphological characteristics of ornamental bromeliads

Three ornamental bromeliads, i.e. Aechmea ‘Maya’ (CAM), Aechmea fasciata ‘Primera’ (CAM) and Guzmania ‘Hilda’ (C₃) were grown under greenhouse conditions at ambient (380 ppm) and elevated (750 ppm) CO₂. The effects of long-term exposure (34 weeks) to elevated CO₂ on growth and morphological traits constituting the ornamental value were assessed.     

Root zone temperature,plant growth and yield of broccoli [Brassica oleracea (Plenck) var. italica] as affected by plastic film mulches

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.     

Effect of partial rootzone drying on growth, gas exchange, and yield of tomato (Solanum lycopersicum L.)

Three levels of partial rootzone drying (PRD) were evaluated and compared with conventional irrigation, in terms of gas exchange, water relations, growth, yield, fruit quality, and water use efficiency in tomato (Solanum lycopersicum L.) saladette-type plants growing in pots with volcanic material and drip irrigation. There were four treatments, a control, in which available water (AW) in the whole root system was allowed to fall to 90%; PRD90-30, in which on one side of the divided root AW was allowed to fall to 90% and on the other side it was allowed to fall to 30%; PRD70-30, in which on one side of the divided root AW was allowed to fall to 70% and on the other side it was allowed to fall to 30%; PRD50-30, in which on one side of the divided root AW was allowed to fall to 50% and on the other side it was allowed to fall to 30%. When each treatment reached the desired AW level they were then irrigated. At the same time, when on one side AW reached values ≤30% irrigation was shifted to the other side. Results showed a significant decrease of leaf water potential up to 14% in PRD plants compared with control. Shoot dry weight and leaf area decreased in relation to substrate available water in PRD plants. Stomatal conductance and transpiration rate were lower, up to 31 and 18%, respectively, in plants with PRD compared with control. However, CO₂ assimilation rate was similar among treatments which along with the reduction of transpiration in PRD plants, increased instantaneous water use efficiency by 28, 25, and 33% in PRD90-30, PRD70-30, and PRD50-30 treatments, respectively, compared to control. Yield, number of fruits and fruit total soluble solids content were similar among treatments. An increase of 25% in fruit titratable acidity was reached in PRD50-30. Fruit firmness increased up to 31% in PRD treatments. PRD treatments allowed a water irrigation saving up to 46%.     

不同镉水平对白菜生长及抗氧化酶活性的影响

 不同镉(cd)水平对白菜[Brassica campestris L．ssp．chinensis (L．)Makino]两个品种生长及抗氧化酶活性研究结果表明：cd 1 mg·L^-1 对两品种生长(除‘杭州油冬儿’地上部干质量)及叶绿素 含量无显著影响，cd 10 mg·L^-1显著抑制植株生长(除‘沪青1号’根干质量)，减少叶绿素含量。cd可诱导叶片中活性氧0₂^-. 、H₂O₂的产生，引起膜脂过氧化产物丙二醛(MDA)的累积。Cd 1 mg’L 显著增加‘沪青1号’过氧化物酶(POD)、过氧化氢酶(CAT)及‘杭州油冬儿’抗坏血酸过氧化物酶(APx) 活性。cd 10 mg·L 显著降低两品种叶片超氧化物歧化酶( SOD ) 、CAT、APX及‘沪青1号’POD活性， 显著增加脱氢抗坏血酸还原酶(DR)和谷胱甘肽还原酶(GR)活性。     

植保康对普通白菜生长发育和营养品质及土壤状况的影响

采用田间施药方法,研究了不同浓度植保康对大棚中普通白菜生长、硝酸盐含量、营养品质及土壤性质的影响。结果表明,施用植保康后,普通白菜叶片数、最大叶面积和产量均有所提高,其中以植保康施用量22.5 kg?hm-2的效果最为明显。在营养品质方面,不同浓度植保康的施用效果不同,22.5 kg?hm-2处理的植株硝酸盐含量最低,而15.0 kg?hm-2处理的植株VC含量较高。添加植保康有效降低了土壤全盐量,提高了土壤微生物数量。综合各项因素,生产中植保康施用量以22.5 kg?hm-2为最佳。     

CO2加富及亏缺灌溉对菜豆中期与后期生长的影响

为了探明菜豆中期与后期生长对CO₂加富与亏缺灌溉的生理响应,试验设两个CO₂水平:正常大气浓度和倍增CO₂浓度,两个灌溉水平:自然灌溉12次和亏缺灌溉6次,研究CO₂加富及亏缺灌溉对菜豆生长的影响。结果表明,CO₂加富显著提高菜豆生长中期株高与干质量,净光合速率(Pn)与胞间CO₂浓度(Ci)分别显著降低15.48%、37.67%,气孔导度(Gs)显著提高95.83%,菜豆生长后期的叶绿素a/b(Chla/b)显著提高12.29%,水分利用效率(WUE)显著提高46.51%,Ci显著降低12.87%。CO₂加富显著提高亏缺灌溉下生长中期菜豆的株高与干质量,但显著降低根冠比,显著提高叶绿素含量以及Gs;CO₂加富下生长后期的核酮糖-1,5-二磷酸羧化酶(Rubisco)及果糖-1,6-二磷酸酶(FBPase)活性分别显著提高78.05%与88.69%,CO₂加富使亏缺灌溉下碳酸酐酶(CA)与FBPase活性分别显著提高83.73%与64.84%。综上所述,CO₂加富提高菜豆生长中期对亏缺灌溉的适应性,对生长后期影响作用减小。     

Effect of 24-epibrassinolide on growth,yield, antioxidant system and cadmium content of bean (Phaseolus vulgaris L.) plants under salinity and cadmium stress

The plants of Phaseolus vulgaris L. were grown in the presence of NaCl and/or CdCl₂ and were sprayed with 5 μM of 24-epibrassinolide (EBL) at 15 days after transplanting (DAT) and were sampled at 30 DAT and at the end of experiment. The plants exposed to NaCl and/or CdCl₂ exhibited a significant decline in growth, the level of pigment parameters, green pod yield and pod protein. However, the follow up treatment with EBL detoxified the stress generated by NaCl and/or CdCl₂ and significantly improved the above parameters. The NaCl and/or CdCl₂ increased electrolyte leakage, lipid peroxidation and plant Cd²⁺ content, and decreased the membrane stability index (MSI) and relative water content. However, the EBL treatment in absence of the stress improved the MSI and relative water content and minimized plant Cd²⁺ content but could not influence electrolyte leakage and lipid peroxidation. The antioxidative enzymes and the level of proline exhibited a significant increase in response to EBL as well as to NaCl and/or CdCl₂ stress.     

氮、锌营养与青花菜花球发育过程中核酸及钙调素的关系

 青花菜生长发育过程茎端DNA、RNA、总核酸( TNA) 含量在花序分化前逐渐上升, 分化时达到高峰, 分化后一度下降, 分化1 周时开始回升, 至花球膨大期达到小高峰,花球膨大后期逐渐下降。RNA/ DNA 比值于花序分化前急剧下降, 分化后进一步下降, 现蕾后花球发育膨大期间逐渐回升。茎端钙调素( CaM) 含量在花序分化前逐渐上升, 分化1 周时达到高峰, 花球发育和膨大过程中逐渐下降。氮( N) 、锌( Zn) 营养可促进核酸和CaM 的代谢, 但不同N、Zn 营养组合使核酸合成活力有所不同, 适宜的N 以及增施Zn 对CaM 的合成有显著促进作用。     

The impact of sodium chloride on root growth,cell division,and interphase silver-stained nucleolar organizer regions (AgNORs) in root tip cells of Allium cepa L.

To evaluate genetic damage, parameters including root growth, chromosomal aberrations, and interphase silver-stained nucleolar organizer regions (AgNORs) in root tip cells of Allium cepa L. were investigated after treatment with NaCl (40–160 mM). The results showed that NaCl caused a decrease in root growth. All concentrations of NaCl showed an inhibitory effect on dividing cells in root tips of A. cepa L. and caused a reduction in mitotic index values. Upon exposure to NaCl, roots exhibited various mitotic abnormalities, including c-mitosis, anaphase bridge, and chromosome stickiness. In addition, interphase cells with micronuclei, budding nuclei, and unequal-sized nuclei were observed. Moreover, total cell aberration increased with increasing NaCl concentration. For AgNOR parameters, the average number of AgNORs per nucleus decreased in roots treated at all NaCl concentrations. The singular AgNOR area and whole AgNOR area in the nucleus containing 1–3 AgNORs were inversely proportional to NaCl concentrations.     

Effects of N–P–K deficiency and temperature regime on the growth and development of Lilium longiflorum ‘Nellie White’ during bulb production under phytotron conditions

One-year-old scale bulblets of Lilium longiflorum Thunb. ‘Nellie White’ (Easter lily) were grown under a combination of six constant day/night temperature regimes and five N–P–K nutrient treatments under short days for 107 d (growing period 1 or GP-1) to compare the effects on growth and development and bulb production. Results during GP-1 were as follows: failure of bulblets to produce a shoot (“no-shows”) was found at high temperatures (30/26 and 26/22 °C) and not influenced by the nutrient treatments. Flower bud abortion was observed in the minus-N, minus-P, and minus-N–P–K treatments at high temperatures (30/26 or 26/22 °C), but not observed at any temperatures in the complete and minus-K treatments. The loss of bulb fresh weight in minus-N treated bulblets was less than in the other treatments resulting in less root and shoot growth in the minus-N treatment. At the intermediate temperatures where growth was highest, omission of N, P, K, or all three resulted in losses in stem bulb fresh weight, stem plus leaf fresh weight, number of flowers, and stem root fresh weight. Omission of N, P, or all three nutrients resulted in lowest basal root fresh weight. Bulb N and K concentrations were lowest in plants grown with complete nutrient solution at the two coldest temperature regimes (14/10 and 10/6 °C). Bulb P concentration was lowest at the three coldest (18/14, 14/10 and 10/6 °C) and the warmest (30/26 °C) temperature regimes. Stem length was shorter when P was omitted. Omission of any of the three nutrients resulted in lower concentrations of the other nutrients. The one exception was where low K did not affect N concentration. In the second phase of the experiment, plants grown at 18/14 °C and irrigated with the complete nutrient solution for 107 d (GP-1) were continued at this day/night temperature regime and five N–P–K nutrient treatments for another 89 d under long days (growing period 2 or GP-2). Results during GP-2 were as follows. Basal bulb yield was not impacted by omission of N, P, or K, or all three. Of all growth measurements, only stem plus leaf fresh weight was lower and only when all three nutrients (minus-N–P–K) were omitted. At the end of GP-2, basal bulb concentrations of N and P did not differ from the concentrations in bulbs at the beginning of GP-1; however, K concentration was lower at the end of GP-2. Omission of N or P further resulted in lower bulb K concentration, suggesting that a moderate supply of N, P, and K be applied during GP-2 since an additional year of bulb production is needed to produce forcing-sized bulbs.     

Effects of diurnal temperature alternations and light quality on growth,morphogenesis and carbohydrate content of Cucumis sativus L.

The effects of the difference (DIF) between day/night temperature (DT/NT) and end-of-day (EOD) light quality on growth, morphology, dry matter (DM) content and carbohydrate status in cucumber (Cucumis sativus L.) were examined. Plants were grown under a 12 h high light intensity period and DT/NT of 25/19 °C (positive DIF) or 19/25 °C (negative DIF) in combination with an exposure of 30 min EOD-red (EOD-R) or far-red (EOD-FR) light. A significant interaction between DIF and EOD light quality was found on morphology, DM and carbohydrate content in axial plant organs like stems and petioles, but not in leaf blades and roots. Positive DIF induced taller stems, and higher DM and carbohydrate content than negative DIF when the plants were grown under EOD-R. The stems developed under EOD-FR were tall and accumulated the highest content of DM and carbohydrates and only small differences were found between positive DIF and negative DIF. Under EOD-R a higher content of glucose and fructose was found under positive than negative DIF, while EOD-FR light resulted in a high glucose and fructose content under both positive and negative DIF and thereby equalized the effect of the two temperature treatments. The results show that positive DIF can induce similar responses in elongation growth, DM and carbohydrate accumulation as EOD-FR, and further that phytochrome status interact with the responses to alternating DT and NT.     

The effects of foliar applied CaCl2·2H2O,Ca(OH)2 and K2CO3 combined with the surfactants Glucopon and Plantacare on gas exchange of 1 year old apple (Malus domestica BORKH.) and broad bean (Vicia faba L.) leaves

Calcium chloride, calcium hydroxide, potassium carbonate and the alkylpolyglycoside surfactants Glucopon 215 CSUP and Plantacare 12 UP are salts applied to leaves as foliar nutrients and fungicides. These chemicals were sprayed on apple (Malus domestica BORKH.) and broad bean (Vicia faba L.) leaves. Stomatal conductance and rates of net photosynthesis were measured continuously in the light and in the dark using a Portable Photosynthesis System CIRAS-1. All compounds with the exception of Ca(OH)₂ affected stomatal conductance and net photosynthesis, albeit to different degrees. In light, Plantacare either alone (0.2 g l⁻¹) or in combination with CaCl₂·2H₂O (5 g l⁻¹) or K₂CO₃ (5 g l⁻¹) caused a rapid initial increase in stomatal conductance during the first 1–3 h after spraying on the leaves, maximum conductances were observed about 6 h after application. A rather high stomatal conductance was observed during the dark period when Glucopon (0.2 g l⁻¹) was applied either alone or in combination with Ca(OH)₂. The combination CaCl₂·2H₂O + Glucopon did not cause this elevated stomatal conductance during the dark. CaCl₂·2H₂O reduced stomatal conductance in combination with both Glucopon and Plantacare. The surfactant Plantacare reduced net photosynthesis during the first light period (12 h), if applied alone or in combination with CaCl₂·2H₂O. Treatment of broad bean leaves with K₂CO₃ + Plantacare resulted in a rapid decrease in net photosynthesis during the first hour, and then the rates of net photosynthesis increased rapidly and approached to those of the water control. The effects of surfactants and salts on net photosynthesis had nearly disappeared by the beginning of the second light period. Non-specific glycosidases presumably cleaved the glycosidic bond between the alkyl and the sugar moieties during the preceding night. Our data showed that foliar applications of CaCl₂·2H₂O and K₂CO₃ together with alkyl polyglycoside surfactants can affect gas exchange. However, the effects of the chemicals at the concentrations used in our study were not very large and were transient. They practically vanished within 24 h and a detrimental effect on growth and development of crops was not likely.     

Effects of thermoperiodicity and plant population density on stem and flower elongation, leaf development, and specific fresh weight in single stemmed rose (Rosa hybrida L.) plants

Thermoperiodicity, i.e. growth in the alternating temperature regime with the same diurnal mean compared with growth at the constant temperature at which optimal growth occurs, was studied at three plant population densities in four cultivars of Rosa hybrida L. Single-node cuttings with five-leaflet leaves were excised and grown as single-stemmed rose plants at an average photosynthetic photon flux density of about 260 μmol m⁻² s⁻¹ and supplied with carbon dioxide at about 1000 μmol mol⁻¹. The optimal constant temperature regime was 22 °C day (20 h)/22 °C night (4 h); alternating temperatures were 23 °C day (20 h)/18 °C night (4 h). The plant population densities were 100, 131 and 178 plants m⁻² of bench area. Thermoperiodicity was absent, or could not be detected, in the parameters related to the growth period, the formation of fresh biomass, the bloom quality, and most parameters related to shoot elongation. However, classic thermoperiodic effects of alternating regime were significant in the cultivars Red Velvet and Sonia, with shoot elongation promoted (7.1 and 10.5%, respectively) in the growth phase from onset of axillary bud growth until the flower bud became visible. Compared with the other two cultivars, plants of Red Velvet and Sonia tended to develop longer internodes. The results, obtained concurrently at three different plant population densities, suggest that thermoperiodicity can affect (single-stemmed) plant growth and development in R. hybrida. Increased plant population density also increased plant height at visible flower bud, but the bloom quality, expressed as specific fresh weight, and the flower height at anthesis was decreased at the highest density. Increased plant population density increased the number of five-leaflet leaves developed in Red Velvet, but had no effect on leaf number in Texas and Sonia, while, in Lambada the leaf number was decreased at the highest density.