A Note on Vessel Structure in the Xylem of Roots of M.XVI Apple Rootstock

A strain of arabis mosaic virus, introduced in unsterilized compost, caused severe disease and complete loss of crop in cucumbers under glass. The virus was transmitted by sap inoculation to 42 out of 73 plant species. Infected Nicotiana clevelandii plants were freed from the virus when grown at 38° C. for three weeks. Although closely related serologically to isolates of arabis mosaic from raspberry and Sambucus nigra, the cucumber isolate did not protect some plants against the Sambucus isolate. Purified virus preparations contained “ spherical ” particles about 30 mμ diameter, and produced specific light-scattering zones in density-gradient centrifugation.     

Production of virus-free plantlets by anther culture of LiliumבEnchantment’

Anthers of the LiliumבEnchantment’, excised at the uninucleate microspore stage, were cultured on MS media containing 6% sucrose with auxin and cytokinin. When anthers were cultured on the medium with 2 mg l⁻¹ picloram and zeatin, 12–86% of them formed nodular calli. Anthers excised from greenhouse- and field-grown plants showed different responses: anthers of greenhouse-grown plants had a significantly higher capability to form callus and regenerate bulblets than those of field-grown plants. In anthers from greenhouse-grown plants, bulblet formation was dependent on the time at which anthers were excised from donor plants: anthers collected from early forced mother-plants had a higher capability of forming bulblet than others. All regenerated plantlets were diploid, which was substantiated by histological observation showing that the anther-derived calli originated from anther wall tissues. Virus tests by ELISA were made for 49 plantlets selected randomly at transplanting: 20 plantlets (41%) were virus-free, and the rest showed positive reactions for lily symptomless virus, cucumber mosaic virus and/or tulip breaking virus.     

The oxygen content of flowing nutrient solutions used for cucumber and tomato culture

The oxygen (O₂) content of flowing nutrient solutions was monitored periodically at various points along and across the gullies of a nutrient-film culture system (NFT). The O₂ content of solution in which mature cucumber plants were growing was more depleted than that of those in which tomatoes were growing. In good weather there was a marked depletion of O₂ in the nutrient solution as it flowed from the inlet to the lower end of gullies containing cucumber plants, which was not found in gullies with tomato plants. On sunny days, the O₂ content of the solutions in which cucumbers were growing varied through the day at all points in the gullies and was lowest in the afternoons.A cucumber crop was grown from the seedling stage to maturity in 3 NFT gullies containing nutrient solutions with O₂ contents controlled at different levels. Day-to-day variations in O₂ content of the nutrient solutions were recorded throughout the duration of the experiment and the effects of these on the growth, development and yield of the plants was measured. Growth rates, root mass, root appearance, leaf area, water consumption and yield were reduced by low O₂ levels in the nutrient solutions.     

Growth of the Strawberry Plant in Relation to Nitrogen and Phosphorus Nutrition

Strawberry plants were grown in conditions producing moderate or severe deficiencies of phosphorus and nitrogen, and the effect on leaf growth assessed in terms of weight and area increases, and the number and size of their constituent cells. Deficiency of both phosphorus and nitrogen reduced the rate of leaf production. Decreased leaf areas were due almost entirely to lower cell numbers and, to a lesser extent in severe deficiency, to smaller cells. The rate of cell production was markedly reduced by phosphorus and nitrogen deficiency, but continued until maximum leaf area was attained, increases in mean cell size having ceased earlier. There was no nutritional effect on cell number or cell size before leaf emergence and it is suggested that the rapid divergence of response thereafter may be related to photosynthetic development after emergence.

The effect of phosphorus and nitrogen deficiency on potential fruit yield was confined to the inhibition of branch crown proliferation and the lack of available sites for flower initiation. There was no effect of nutrient level on the number of flowers initiated on each apical meristem. Results suggest that any manipulation of nutrient status aimed at increasing fruit yields should be predominantly concerned with increasing branch crown formation, thus providing additional sites for flower initiation.     

菊花缺镁症的营养诊断研究

以镁不同浓度砂诱导菊花缺镁的典型症状，研究缺镁后植株体内矿质成分及生理生化特性的变化，提出营养诊断方法。结果表明，初花期是进行诊断的可靠时期，叶片能良好地反映供镁状况，此时，菊花叶片镁素营养的监界范围是０．２０４％～０．２１５％，缺镁的监界值为０．１９％，叶片钾镁比值低于３２为正常，过氧氢酶活性可作为诊断的辅助指标。菊花无土栽培时，营养液中镁浓度至少应在１４ｍｇ／１以上才不致发发生缺镁症。     

Against the wall—Root growth and competition in four perennial winter hardy plant species grown in living walls

Plants in living walls face challenges from intraspecific and interspecific competition from plants around them, as well as water and nutrient availability in the growing media. This paper explores these challenges using four different species of hardy perennials.Campanula poscharskyana ‘Stella’, Geranium sanguineum ‘Max Frei’, Sesleria heufleriana and Veronica officinalis ‘Allgrün’ were grown in two types of vertical growing media, made of either coir or stone wool, in transparent boxes under greenhouse conditions. In the media, plants were placed above each other, two plants of same species, two plants of different species, or a plant grown alone. Root frequency was registered over 56 days and the activity of individual root systems was studied through uptake of ¹⁵N. In addition, plant dry weight and N content as well as water content in the growing media were measured at cessation of the experiment.Shoot and root growth as well as nutrient content in plants were higher in coir than in stone wool and plants placed at the top position had significantly higher biomass than at the bottom position. The stone wool media had significantly higher water content in the lower part of the media while the coir media had water more evenly distributed. Species differences in root frequency were found. Campanula and Geranium showed strong root growth and had root frequencies of up to 0.9, whereas Sesleria and Veronica had less root growth, in some cases only root frequencies around 0.3. The species reacted differently to root competition and planting position and there were differences in the competitive ability between the species. Campanula and Geranium were not affected by competition, whereas both Veronica and Sesleria showed altered root growth due to competition depending on the growing medium. When Geranium was grown above Veronica in stone wool, plant biomass and ¹⁵N uptake increased in Veronica indicating environmental modification, with one species improving the growing conditions for another.The results revealed that growing plants vertically in a living wall is complex, and that choice of growing medium and species composition is important for a successful living wall. Planting combinations should therefore be tested before being used in commercial applications.     

杜鹃无土栽培基质配方的研究

 采用发达国家已经大量应用的潮水式(Ebb&Flow)底面灌施营养液栽培系统，以盆栽杜鹃品种‘Mission Bell’作为试材，筛选出适合杜鹃盆花无土栽培 基质配方。混有草炭的M1(体积比：草炭土3+蛭石3+珍珠岩3)、M2(草炭土3+蛭石3+砻糠3)和M4(草炭土2+蛭石2+珍珠岩2+著糠2+腐叶土2)基质配方栽培的植株表现较好，尤以M1处理，即‘草炭土3+蛭石3+珍珠岩3’的等量配方为最优，而椰壳并不适合盆栽杜鹃的植株生长。土壤的理化分析和植物体分析结果表明，营养液灌溉处理后基质的pH值基本相同，但EC值的增幅很大，是由封闭系统内营养液中盐分累积所致；盆内基质中的矿质营养元素和阳离子交换量也明显增加；植物体的营养元素含量水平普遍较高，非常符合杜鹃类植物的生长条件与特殊需求。     

球根鸢尾的病毒鉴定及试管脱毒成球技术

对上海地区球根鸢尾进行了病毒病害调查。经检测初步确定球根鸢尾普遍存在鸢尾重花叶病毒、鸢尾轻花叶病毒、水仙潜隐病毒３种病毒的复合侵染。对带毒种球进行茎尖组培脱毒,得出了茎尖诱导成芽、芽成球及小球生根的培养基配方。将组培苗在试管苗、成球苗、移栽苗等不同时期进行病毒检测,结果表明,小于１．０ｍｍ的茎尖诱导的幼苗可脱去上述３种病毒。     

Growth and mineral nutrient content of developing fruit on banana plants (Musa acuminata AAA, ‘Grand Nain’) subjected to water stress and recovery

Summary

The effects of progressive water stress and subsequent re-hydration on fruit growth and mineral nutrient content were investigated in banana plants (Musa acuminata AAA, ‘Grand Nain’) under field conditions. Water stress was imposed by suspending irrigation from flower emergence for 63 d, then continuous re-watering was restored. These adverse conditions reduced fruit growth, fruit size, yield, and delayed fruit maturation. Fruit fresh and dry weights decreased with photosynthetic rate and soil moisture content during the stress period. In relation to nutrient accumulation, the main effect of drought was to reduce potassium levels, which is the major mineral nutrient in banana. In contrast, all the other minerals analysed either increased (i.e., calcium, sodium, iron and zinc), or remained stable (i.e., nitrogen, phosphorus, magnesium, manganese and copper) under the drought treatment, which generated a positive effect on the organoleptic properties of the fruit. After re-hydration, the mineral nutrient content of banana fruit was similar between stressed and non-stressed plants. The data illustrate the ability of banana to maintain relatively normal mineral contents and functional fruit tissues, which continued to expand after re-hydration, despite the long period of water stress. However, banana fruit lost commercial value, with a reduction in size and biomass after the water stress period.     

BTH诱导西瓜甜瓜抗病毒病研究

为了考察S-甲基苯基(1,2,3)噻二唑-7-硫代羧酸酯(benzothiodiazole,BTH)诱导西瓜对小西葫芦黄花叶病毒(Zuccini yellow mosaic virus,ZYMV)、西瓜花叶病毒(Watermelon mosaic virus,WMV)与甜瓜对黄瓜花叶病毒(Cucumber mosaic virus,CMV)的抗病效果,分别在接种ZYMV、WMV、CMV前喷施BTH。结果表明:在接种ZYMV、WMV、CMV前3d用25μg/mLBTH处理西、甜瓜,4周后植株的病情指数减少,相对防效分别为55.6%、56.8%、78.2%;进一步研究发现,经BTH处理后,诱导时间的长短对病情指数有一定的影响;BTH对病毒病的防治效果优于病毒A、病毒K、宁南霉素、芸薹素内酯。     

Sucrose,water and nutrient use during stage II multiplication of two turmeric clones (Curcuma longa L.) in liquid medium

Two clones of turmeric (Cucruma longa L.) were assessed nine times during a 28-day culture period in double phosphate MS liquid medium containing 2%, 4% and 6% sucrose. The phase of rapid shoot bud multiplication lasted for 21 days or less, in both clones in all media. The maximum multiplication rate was 3.4× at 20 and 19 days, with 3.9% or 4.7% initial sucrose concentration being optimal for the clones 9-3 and 35-1, respectively. Dry mass increased over the entire culture period and was greatest with 4.8% or at least 6% initial sucrose concentration for the two clones, 9-3 and 35-1, respectively. Maximum tissue water mass required 2.8% and 3.9% initial sucrose, respectively, in the two clones. Tissue relative water content (tissue water mass/fresh mass) was better correlated with sucrose concentration in medium, than the osmolality of medium, for both clones at all sucrose concentrations. Relative water content increased over time (water was incorporated more rapidly than dry mass in growing tissue) and sucrose concentration in media decreased over time (sucrose was used at a relatively more rapid rate than water). The concentrations of 10 nutrients (P, K, S, Zn, Mg, Fe, B, Ca, Mn and Cu) and Na assayed in time course all decreased rapidly over time. The rates of nutrient use were better related to growth of plant mass than shoot bud multiplication. P and Cu were completely depleted from medium before the end of the culture period. P concentration in tissues was in the lower ranges of that considered optimal, and Cu was in excess concentrations, based on comparison to high-yielding field-grown plants. Sugar, water, and nutrient use were more closely related to plant mass than shoot multiplication. The stationary phase of bud multiplication was coincident with continued growth of tissue dry and water mass. Among inorganic nutrients, lowered concentrations of P were most likely related to the stationary phase of bud multiplication, but still permissive of dry and water mass increases. Lowered availability of sugar, other inorganic nutrients, or less available water, did not precede day 21 and the end of active shoot bud multiplication. In batch culture, the concentration of a nutrient that is rapidly used (e.g. sucrose) does not remain at an optimal range for a prolonged period of time.     

Flowering,vegetative growth and mineral nutrition of pot chrysanthemums in sawdust and peat-life media

Plants of Chrysanthemum morifolium Ramat ‘Mountain Peak’, ‘Goldstar’ and ‘Cir Bronze’ were grown in sawdust, sawdust mixed with Ca(NO₃)₂ 7 weeks before planting and held at 20°C (unheated), or at 43°C (heated), and in a sphagnum-peat/vermiculite mix (peat-lite). C:N ratios for the sawdust media at planting were 265.9, 125.7 and 123.3, respectively. Plants grown in each medium received nutrient irrigation containing macro- and microelements, with N at 150, 200 or 250 mg l^?1.Days to full flower development, and flower diameter at harvest were not influenced by medium or irrigation N concentration. Plants grown in peat-lite produced the thickest and longest stems, although the stature of plants in all media was judged to be commercially acceptable. Plants grown in unheated sawdust pre-mixed with Ca(NO₃)₂ produced the thinnest and shortest stems.Leaf concentrations of N, P, K and Mg at harvest were highest in plants grown in peat-lite. Accumulation of Ca, B, Fe, Mn, Cu and Zn was more variable. With the exception of P, foliar nutrient concentrations in all plants were optimal or above published optimal ranges. The onset of flower senescence occurred an average of 1 day earlier in sawdust-grown plants.     

Induced androgenesis as a biotechnology method for obtaining DH plants in Daucus carota L.

The influence of various factors on the efficiency of obtaining double haploid lines in anther cultures was examined in Daucus carota L. The impact of the genotype, the formation of donor plants and the growth conditions was investigated. The effects of various regeneration media were analysed. Acclimatisation of androgenic plants and their evaluation were also conducted. Androgenesis was induced on B₅ medium containing 2,4-D and NAA at 0.1 g·L^?1. Depending on the genotype, 1.2–305.3 embryos per 100 anthers were obtained. The highest number of embryos (5.5 per 100 anthers) was obtained from donor plants with the first-order shoots containing one umbel. Cultivation of donor plants under controlled conditions improved the number of embryos from 305 in the open field to 1764 in the growth chamber. Regeneration of plants from androgenetic embryos proceeded most effectively on B₅ medium without hormones and amino acids. Regenerated plants adapted in over 60%. Ploidy analysis showed the presence of 92% of plants with a doubled chromosome set and 8% with a tetraploid number of chromosomes. Plants with a doubled chromosome set were 73% homozygous for the glucose phosphate isomerase isoenzyme and 100% homozygous for the aspartate aminotransferase isoenzyme, which confirms their gametic origin.     

The effect of nitrate and plant size on nitrate uptake and in vitro nitrate reductase activity in strawberry (Fragaria × ananassa cv. Selva)

Nitrogen plays a major role in the growth and yield of strawberry. For optimizing nitrogen fertilizer application, it is necessary to understand the response of strawberry to nitrogen supply. The objective of this study was to determine the effect of nitrate supply and plant size on strawberry nitrate uptake and nitrate reductase activity (NRA). Strawberry plants cv. Selva were grown under growth chamber conditions in nutrient solutions containing 0, 0.1, 0.25, 0.7 or 4 mM nitrate. Cumulative nitrate uptake increased with the increase in nitrate supply. Increasing nitrate concentrations from 0 to 0.25 mM decreased leaf NRA; however, further increases to 4 mM nitrate restored NRA to activities observed at 0 mM nitrate. The activity of NADH- and NADPH-dependent NR was similar at every external nitrate concentration. Activity of NR was greater in the smallest plants and decreased as plant size increased. However, increasing external nitrate concentration increased nitrate uptake, but had not the same effect on nitrate reductase activity, showing that NRA and nitrate uptake are not necessarily correlated.     

Vector analysis in the study of the nutritional status of Philodendron cultivated in compost-based media

Compost (CP) made from 70% ligno-cellulosic compounds and 30% sewage sludge was studied as a component of growing media in a 6-month Philodendron cultivation. CP's agronomic viability was evaluated via four plant-growth media containing 25–50–75–100% CP and white sphagnum peat (WP) in comparison to a commercial substrate with white and black peat. Plant nutrition conditions were investigated by determining macro- (TKN, P, K, Ca, Mg and micronutrients (Mn, Fe, Cu, Zn, Na) and heavy metals (Ni, Cd, Cr, Pb) in roots and shoot tissues. Data were compared by vector analysis against control. Even if no leaf injuries were visible after 6-months’ growth, a CP ratio of up to 50% caused growth depression of canopy tissues, as attested by the 37 and 36% reduction in total leaf dry weight and leaf area, respectively. Root growth decline was also notable at 25% CP, where 38% root dry weight reduction implied a significant increase (46%) in shoot–root dry weight ratio. The investigation on nutrient tissue content showed high accumulation of Ni, Fe, Cr, Zn, Cd, Mn, Mg and P in roots; Mg appeared related to K deficiency. Above-ground nutritional status showed a severe lack of P, Mg and Mn. Vector analysis suggests the sewage sludge CP in Philodendron pot cultivation produces many such effects like direct toxic action and antagonistic action, resulting in a general nutrient imbalance in plants.     

果树根构型及其与营养和激素的关系

不仅树型(株型)影响果树产量和质量,根构型对果树生产也有重要意义。介绍了根构型的特点、根构型对环境营养状况的反应及其对养分吸收的影响,以及营养因素和激素对根构型的影响。指出果树根构型比1年生作物更加多样化,骨干根与毛细根的发生和生长状况是影响根构型的主要因素,果树可以通过根系变长、变细以及数量和密度的增加等方式改变根构型;生长素、细胞分裂素、乙烯和赤霉素等植物激素对根构型构建起主要调节作用,营养元素可以通过内源激素调控果树的根构型。根构型与养分吸收有很大的关联,通过构型的改变,可以增加根系与介质的接触表面积,促进营养元素的吸收利用。加强果树根构型研究,揭示果树根构型与营养的关系,构建理想根构型,对于果树根系管理和养分的高效利用有重要价值。     

Micropropagation of Cryptanthus with leaf explants with attached intercalary meristems excised from greenhouse stock plants

By using the leaves with attached intercalary meristems from greenhouse grown stock plants, five cultivars of Cryptanthus were cultured on modified MS media with 4.5 μM NAA and IBA and 3 μM BA to induce adventitious shoot formation from callus tissue. Contamination was 17–21% for explants taken from stock plants which were sprayed weekly with Agribrom and 27–75% for those taken from stock plants which were not treated. More than 99% true to type plantlets were obtained from non-chimeric plants. Green and albino plantlets were obtained from chimeric plants. The chimeric C. ‘Coster's Favorite’ DeCoster also produced a few chimeric plantlets with intermarginal pink stripes in addition to the green and albino plantlets. Most of the non-chimeric plants took a shorter time to produce plantlets of transplantable size (8–12 mm) than the chimeric ones. Except for albino plantlets, survival rate of plantlets exceeded 95%. A minimum average of 500 rooted plantlets can be obtained in a year from a single well-callused leaf explant. The protocol in this report should speed up the mass production and introduction of desirable new cultivars and hybrids of non-chimeric Cryptanthus.