Effect of different levels of nitrogen in nutrient solution and crop system on nitrate accumulation in endive

With the objective of studying the effect of two nutrient solutions and two crop systems (greenhouse and openfield) on nitrate accumulation, incidence of tipburn and chlorophyll content, endive (cv. Cuartana) was planted in 8 L pots, filled with a mixture of coconut coir:perlite (1:1) in three different cycles C1 (winter), C2 (spring) and C3 (summer). Plants were irrigated with two nutrient solutions of different nitrate content: S1, low ([NO^?₃] = 7.91 mmol L^?1) and S2 moderate nitrate content ([NO^?₃] = 16.91 mmol L^?1). Nitrate content was determined by reflectometry, tipburn was evaluated using a qualitative scale and chlorophyll content by soil plant analysis development(SPAD) values. Plants irrigated with S2 showed higher nitrate accumulation in leaves in all cycles, however, no influence of the nutrient solution was observed on the incidence of tipburn. Greenhouse-cultivated plants accumulated more nitrates than those cultivated in open field and also showed a higher incidence of tipburn and SPAD values.     

Genotype by environment interactions of heat stress disorder resistance in crisphead lettuce

Lettuce is a cool season crop susceptible to physiological disorders when exposed to supra optimal temperatures. Genotype (G) by environment (E) interaction (GE) of rib discolouration, tipburn, premature bolting and ribbiness in crisphead lettuce was characterized under high temperature and long day growing conditions. Replicated data of 10 crisphead lettuce varieties from two plantings in each of four growing seasons at two locations in Quebec were analysed using the GGE biplot method. Head-weight-over-stem-length ratio, ribbiness, rib discolouration incidence and tipburn incidence were affected (P = 0.00001) by E, G and GE. E explained more variation in head-weight-over-stem-length ratio (77.1%) and rib discolouration incidence (77.3%) than G and GE, whereas GE explained more variation (72.4%) in tipburn incidence and G explained more variation (38%) in ribbiness. Strong crossover GE was detected with rib discolouration and tipburn incidence, but not with head-weight-over-stem-length ratio and ribbiness. Under heat stress, varieties of the Vanguard group had lower ribbiness than those of the Great Lakes group. Cultivar 'Estival' showed consistent resistance to bolting, ribbiness, tipburn and rib discolouration across all E.     

盐钙胁迫下大白菜干烧心病的发生及矿质营养分配

以大白菜抗、感干烧心病自交系(C8、651A)及其杂交种F1代(651AXC8,C8X651A)为试验材料,进行无钙营养液和100mmol.L-1NaCl处理,20d后调查植株的矿质元素含量、干重和发病率。结果表明,苗期营养液无钙处理比根际盐胁迫更容易导致大白菜干烧心病的发生,无钙处理下651A的发病率显著高于盐胁迫处理,且叶柄和叶片中钙含量与干烧心病发生正相关,正反交均能提高品种抗性。盐钙处理均抑制了氮磷钙的吸收,盐处理下品系651A叶片的氮、磷、钙吸收抑制率分别为25.43%、22.00%、31.18%;无钙处理使叶柄中钾镁含量显著增加,651A叶柄中钾镁含量分别比对照增加51.00%和12.08%;抗病品系651A和正反交F1代的钙钠含量均显著高于感病品系C8。     

Increase of leaf tipburn in chervil and lettuce by restricting volume of growing medium

Abstract

The objective of this investigation was to examine the effect of restriction of growing medium volume on the level of tipburn in chervil and leaf lettuce. Chervil: The plants were grown in different sizes of rock wool cubes: a. 31 cm³, b. 64 cm³, c. 135 cm³. The incidence of tipburned leaves decreased by increasing the size of cubes. Leaf lettuce: Plants were grown in different sizes of pots: 12 cm pots with capacity of 0.6 L and 8 cm pots with capacity of 0.25 L. The incidence of tipburned leaves increased by decreasing pot size.     

Effects of salt concentration and cation balance in soils on leaf tipburn and calcium content of strawberry leaves and fruit

Abstract

Strawberry plants cv. Cambridge Favourite were grown in pots of soil in a glasshouse. A relationship was found between the function ^aCa: S^aCations(soil solution) x guttation score, the severity of leaf tipburn and the calcium concentration in the emerging leaf. Slightly less well related but of more practical use was the function ^cCa: S^cCations/electrical conductivity of the soil solution; values below 0.15 mS^‐1 resulted in increased tipburn and reduced calcium concentrations in emerging leaves and in the fruit.     

Evaluation of butterhead lettuce cultivars for winter production under a shadenet structure

Incorrect selection of cultivar leads to profit loss due to variability in yield and in quality characteristics of butterhead lettuce. Nine butterhead lettuce cultivars were evaluated in soil cultivation under a 40% white shadenet structure during the winter season on an experimental farm of the Agricultural Research Council – Vegetable and Ornamental Plant Institute (ARC-VOPI). The experiment was laid out as a randomised complete block design with five replicates. During harvest, 10 plants from each cultivar per replicate were assessed for yield, and five uniform heads were cut longitudinally for internal quality assessment. Quality assessment included compactness, uniformity, tipburn, disease tolerance and bolting tolerance. Results showed that head mass, height, diameter, uniformity, compactness, tipburn, disease tolerance and internal quality were significantly affected by cultivar choice. Recommended cultivars which outperformed the control (Ofelia) based on uniformity, tipburn and percentage marketable harvest were Analena, Fabieto RZ, Lobela and Rousso RZ. Results thus indicate that improved yield and quality of butterhead lettuce cultivars can be obtained by selecting the correct cultivar for winter production.     

The relationship between leaf growth,calcium accumulation and distribution,and tipburn development in field-grown butterhead lettuce

The change in calcium (Ca) concentration with time, the distribution of Ca within various leaves, and leaf and tipburn development were studied in field-grown lettuce (Lactuca sativa L.) cultivar ‘Cobham Green’.Ca distribution between and within leaves followed two distinct patterns. The average concentrations in the outer leaves were always higher than in the inner leaves. The concentrations at the periphery of the outer leaves was always greater than in the midrib, whereas for the inner leaves the converse was true.Tipburn only occurred in the inner leaves; it developed on only those leaves and those parts of the leaf which expanded most rapidly.Thus, tipburn development appears to depend on the supply of Ca relative to the rate of leaf growth.     

Inheritance of resistance to tipburn in cabbage

Summary Tipburn resistance was identified as being highly but not completely dominant in three nearly isogenic populations of cabbage. Narrow sense heritability estimates of 0.14, 0.34, and 0.49 and broad sense heritability estimates of 0.64, 0.74, and 0.77 were obtained with 2–4 genes controlling resistance. Analysis of resistance was made under conditions of high fertility, especially high N and plentiful moisture and generally high humidity which together resulted in very severe tipburn in susceptible plants.Journal Paper No. 3038 of the New York State Agricultural Experiment Station, Geneva, New York, USA.     

根际通电栽培对植物工厂生菜生长及叶烧病发生的影响

针对人工光植物工厂内由钙缺乏而引起的叶菜叶烧病频发的问题,以较易发生叶烧病的生菜作为试验材料,采用在生菜根际建立电压为-15kV全天工作的通电系统,使生菜植株带负电,并在地上部生长空间形成正向电场的方法,设置根际通电处理为试验组,无通电处理为对照组,探究根际通电栽培对生菜生长、钙离子吸收以及叶烧病发生的影响。结果表明:1)对照组的生菜植株在第13天发生叶烧病现象,而试验组的生菜则在第15天出现叶烧病,且在第20天叶烧病的发生率降低了46.9%;2)移栽第20天,与对照组相比,试验组生菜植株的地上部和地下部鲜质量分别提高了6.3%和30.9%,干质量分别提高了17.2%和22.4%;3)移栽第10天,试验组生菜的根系活力和Ca~(2+)吸收能力分别较对照组提高了133.3%和108.9%;4)移栽第20天,试验组生菜的气孔导度、蒸腾速率和胞间二氧化碳浓度分别较对照组提高了46.2%、49.0%和5.2%,生菜光合产物的积累也得到提高。综上,在植物工厂综合环控条件下,根际通电栽培能显著改善生菜的生长发育,并能有效地减缓叶烧病的发生。     

The effect of Mg: Ca ratio and osmotic potential of nutrient solutions on calcium transport into emergent leaves of the strawberry plant cv. Cambridge favourite

Strawberry plants, cv. Cambridge Favourite were grown at osmotic potentials of ‐0.2 and ‐0.8 bars in nutrient solutions with magnesium : calcium ratios ranging from 0.3 to 5.6: 1. When the OP was ‐0.8 bars, all plants showed leaf tipburn, guttated little, yielded small volumes of exudate overnight from cut stolons and had small calcium concentrations and contents in their emergent leaves, regardless of the Mg: Ca ratio of the nutrient. No symptoms were seen in plants grown at an OP of ‐0.2 bars, although the calcium concentration in the emergent leaves was smaller when the Mg: Ca ratio of the nutrient exceeded 0.8: 1. The overall salt concentration, which reduced the water potential gradient through the root and prevented development of root pressure at night, was more important than the magnesium to calcium balance of the nutrient solution in causing a local calcium deficiency in emergent leaves of the strawberry plant.