´╗┐ Journal of Applied Horticulture Selected Contents of Year

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Maureen N. Situma, Mariam Mwangi and Richard M.S. Mulwa

Department of Crops, Horticulture & Soils, Egerton University, P.O. Box 536, Egerton - 20115, Kenya.

Key words: Lily, bulb, dormancy, gibberellic acid, benzyl adenine, chilling, flowering

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 26-30.

Abstract: Dormancy in Oriental lily bulbs (Lilium spp) is a major bottleneck in lily flower production by small scale farmers because they cannot afford expensive chilled bulbs that have been induced to break dormancy. Thus for developing alternative and low cost dormancy mitigation techniques, the study investigated the effects of lily bulb pre-treatments with benzyl adenine (BA) and gibberellic acid (GA3) on dormancy breaking, emergence rates, time to flowering and bulb multiplication. Bulbs were pre-soaked for 24 hours in prepared solutions of various concentrations of BA and GA3 (0; 25; 50; 100 and 150 mg/L) and their combinations, plus a positive control of chilled bulbs. An unbalanced factorial arrangement in a randomized complete block design with three replications was used. The experiment was repeated in two seasons. Results showed that treating bulbs with BA and GA3 significantly influenced dormancy breaking in both the trials and was comparable with the chilling treatment. The highest sprouting was observed in bulbs treated with 50 mg/L BA (92%) and 50 mg/L GA3 (96.67%) in both trials; compared to chilled bulbs with 100% sprouting. The number of days to 50% bulb emergence was significantly reduced in trial 1 with various combinations of GA3 and BA (50 mg/L:100 mg/L; 150 mg/L:100 mg/L and 150 mg/L :150 mg/L ). Combining the plant growth regulators also decreased the number of days to flowering; with 25 mg/L BA + 150 mg/L GA3; 50 mg/L BA + 100 mg/L GA3; 50 mg/L BA + 150 mg/L GA3 and 100 mg/L BA + 100 mg/L GA, respectively, significantly decreasing the number of days to flowering to 124 compared with 132 for the control in trial 2.
P. Kaur, N. Singh and D. Mukherjee

Laboratory of Plant Physiology and Biochemistry, Kurukshetra University, Kurukshetra-136119, Haryana, India.

Key words: 5-Sulfosalicylic acid, 6-benzylaminopurine, ascorbate peroxidase, catalase, ethanol, guaiacol peroxidase, malondialdehyde, membrane stability index, protein, senescence, sucrose, superoxide dismutase and vase life

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 31-39.

Abstract: This investigation was carried out to assess not only the efficacy of ethanol (EtOH) with that of sucrose (both are the product of plant metabolism) but also with 6-benzylaminopurine (6-BAP) and 5-sulfosalicylic acid (5-SSA) which are well known plant growth regulators (PGRs) to minimize the decline in certain antioxidant enzymes in the cut flowers of Calendua officinalis L. and Salvia splendens Sellow ex J. A. Schultes. An effect of sucrose was also studied when it was present either alone or in combination with other chemicals (EtOH/6-BAP/5-SSA) in the vase solution. Control cut C. officinalis flowers looked fresh for 1-day, while flowers in sucrose solution lasted for about 2-day whereas other chemicals could extend the vase life from 4 to 7 days. The order of effectiveness of applied chemicals was EtOH + sucrose (Suc) > 5-SSA + Suc > EtOH/5-SSA > 6-BAP > 6-BAP + Suc > Suc in C. officinalis whereas it was EtOH/EtOH + Suc > 5-SSA > 5-SSA + Suc > 6-BAP + Suc > 6-BAP > Suc in S. splendens. In both the plants, petals of untreated flowers exhibited a gradual reduction in activities of ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD); and protein levels and membrane stability index (MSI) values whereas malondialdehyde (MDA) level and guaiacol peroxidase (GPOX) activity registered increment. However, individual treatment of metabolites like ethanol and sucrose, plant growth regulators like 6-BAP and 5-SSA were able to reduce not only protein content but also activities of APX, CAT and SOD. The combined effect of EtOH + Suc was more effective than 6-BAP + Suc or 5-SSA + Suc.
P. Verdi, M. Cano and E. Liem

Canadian Humalite International Inc., 15723-116 Ave, Edmonton, Alberta, Canada T5M 3W1.

Key words: Lactuca sativa L., deep water culture growing units, humic substances, plant, root, leaf, growth

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 40-43.

Abstract: Seedlings of lettuce (Lactuca sativa L.) variety Grand Rapids were grown in deep water culture growing units. The units contained growing solution with limited amount of nutrients and different concentrations of humic substances. Six treatments and one control, 12 replications each, were evaluated in a two month period. Only one plant perished from a total of 84, indicating that the growing units were effective. A liquid product containing 13,800 mg L-1 humic substances of small particulate sizing (1.1 ▒ 0.64 ?m in mean diameter) was utilized as a source of humic substances. Significant plant (root and leaf) growth was observed at low product rates between 70 and 500 mg L-1, corresponding to 1 and 7 mg L-1 humic substances. At increased rates, the growth was reduced. At much higher rates, plant growth was again observed, that was likely caused by the presence of nutrients in the product. These experiments demonstrated the efficacy of humic substances on plant growth, a critical finding in the context of sustainable horticulture, in which maximum yields from minimum input would be desired.
N.D. Polara, N.N. Gajipara and A.V. Barad

College of Agriculture, Junagadh Agricultural University, Junagadh - 362 001 (Gujarat), India.

Key words: African marigold, chlorophyll content, flower yield, nitrogen, phosphorus, variety

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 44-47.

Abstract: A field experiment was conducted to study the effect of N and P2O5 nutrition on growth, flowering, yield and chlorophyll content of different varieties of African marigold on the medium black calcareous soil during two consecutive years. The treatments consisted of all combination of three levels of nitrogen (100, 150 and 200 kg N ha-1) and three levels of phosphorus (50, 100 and 150 kg P2O5 ha-1) with three varieties of African marigold viz., Local Orange (V1), Pusa Basanti (V2) and Pusa Narangi (V3). The growth parameters like plant height, number of primary and secondary branches as well as leaf area exhibited increasing trend with increase in nitrogen level which were highest at N3 (200 kg N ha-1). The phosphorus application failed to influence the growth of plant except plant spread. The maximum total chlorophyll content, 1.452 and 1.431 mg g-1, respectively was found due to addition of nitrogen and phosphorus. The higher number of flowers, diameter of flower, number of ray florets per flower and flower yield was recorded at higher level of each nutrient i.e. N3 (200 kg N ha-1), and P3 (150 kg P2O5 ha-1). Number of days to first flower was advanced with increasing levels of N. Variety Pusa Narangi produced the biggest flower diameter (6.20 cm), highest number of flowers per plant (56.34), flower yield (183.0 quintal ha-1), leaf area (13.89 cm2) and total chlorophyll content (1.432 mg g-1) in leaves. The interaction effect of N and P was found significant for plant spread at 60 DAT and at the end of harvest season. The combination N3P3 (200 kg N ha-1 and 150 kg P2O5 ha-1) recorded maximum plant spread (42.87 and 56.65 cm) at 60 DAT and at the end of harvest season, respectively. Treatment combination N2P3 (150 kg N ha-1 and 150 kg P2O5 ha-1) recorded significantly larger flower diameter (7.79 cm).
D.B. Singh, N. Ahmed, A.A. Pal, R. Kumar and A.A. Mirza

Central Institute of Temperate Horticulture, Srinagar-1900 07. J & K. India.

Key words: Apple, Red Chief, anti browning agents, drying, quality, ascorbic acid, citric acid

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 48-51.

Abstract: Apples of Red Chief variety after stabilization at room temperature (20▒2 ░C) were initially washed with chlorinated water (100 ppm sodium hypochlorite) to prevent surface contamination. After manual peeling, apples were cut in to disc shaped slices of 2 and 3 mm thickness (having uniform diameter of 20 mm) and treated with 1% ascorbic acid and 1% citric acid (anti browning agents) for studying their effect on drying time and quality of apple slices. Slice size and pre-drying treatments of ascorbic acid and citric acid has resulted in significant (P<0.05) variation for drying time, rehydration, dry matter contents, firmness, quality and total colour change. Significantly minimum time (300 minutes) for drying of apple slices, maximum rehydration ratio (4.9), and maximum firmness (11.9 RI) was recorded in case of 2 mm slices treated with 1% ascorbic acid and 1% citric acid. Maximum TSS (18.9░ Brix) was recorded in 2 mm slices and 3 mm slices (18.7░ Brix) treated with citric acid and ascorbic acid. Ascorbic acid and citric acid were effective to stabilize the ascorbic acid content and maximum (18.0 mg/100g) was recorded in case of slices of 2 mm thickness treated with 1 % ascorbic acid and 1% citric acid. Similarly size of slices and anti browning agents were significantly effective to reduce the total colour change in apple slices and minimum colour change was observed in 2 mm slices (10.0) treated with 1 % ascorbic acid and citric acid and 3 mm slices (12.25) treated with 1% ascorbic acid and 1% citric acid. It can be concluded that apple slices of 2 mm thickness and pre drying treated with 1% citric acid and 1% ascorbic acid as anti browning agents took minimum time for dehydration with minimum changes in colour, firmness, quality, and retained maximum compositional attributes with minimum browning.
Ravindra Kumar, R. Chithiraichelvan, S. Ganesh, K.K. Upreti and V.V. Sulladmath

Division of Fruit Crops; Division of Plant Physiology & Biochemistry, Indian Institute of Horticultural Research, Hessaraghatta Lake, Bangalore-560 089, Karnataka, India. Faculty of Agriculture, Gandhigram Rural Institute (Deemed University), Gandhigram,

Key words: Fig, growth characters, pruning, fruit quality, tree spacing, fruit yield, photosynthesis, leaf water potential

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 52-57.

Abstract: Effects of tree spacing (5x2 m, 5x2.5 m, 5x3 m, 5x3.5 m and 5x4 m) and pruning (8 buds/cane, 6 buds/cane and 4 buds/cane) on growth, physiological parameters, fruit yield and quality were studied in fig cv. Poona during 3rd and 4th years of planting. Results indicated that the fig responded more to tree spacing than the pruning levels in terms of morpho-physiological characters and yield. With increase in in-row tree spacing from 5x2.5 m to 5x4 m, the vegetative growth parameters like leaf number, shoot length, internodal length, tree spread, tree height and tree circumference and the fruit yield both in terms of fruit number and fruit weight per tree declined under different pruning levels and closer tree spacing of 5x2.5 m recorded higher values. Physiological parameters like photosynthesis rate and leaf water potential remained at higher levels under closer spacing as compared to the wider spacing under different pruning levels. The increased pruning levels from 8 buds/cane to 4 buds/cane resulted in reduction of tree height while yield characters were marginally influenced by the pruning. The interaction effects between pruning and spacing levels were, however, non-significant. Under 5x2.5 m, the average fruit size and TSS recorded the highest values with no marked differences in acidity. The fruit yield calculated on per tree basis showed highest fruit number of 84.3-253.0 and 232.3-321.5 and fruit weight of 2.69-8.61 and 7.43-9.44 kg, respectively during 3rd and 4th year of planting under closer spacing of 5x2.5 m with 8 buds/cane pruning. The yield per hectare under various pruning levels recorded high values under the closer spacing of 5x2.5 m or 5x2.0 m with 8 buds/cane pruning. Overall results showed that 5x2.5 m tree spacing in combination with light pruning level of 8 buds/cane is ideal for achieving higher growth and yield in fig during 3rd and 4th year of planting.
S.K. Dwivedi and Enespa

Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow-226025, U.P., India.

Key words: Wilt disease, Fusarium solani, Fusarium oxysporum f. sp. lycopersici, cellulolytic enzyme, pesticides, Solanum melongena, Lycopersicon esculantum

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 58-65.

Abstract: Soil-borne pathogens (Fusarium solani and Fusarium oxysporum f. sp. lycopersici) were isolated from the diseased plants of brinjal and tomato, identified by morphological analysis viz., PCM (Phase contrast microscopy) and SEM (Scanning Electron Microscopy). These pathogens produced cellulolytic enzyme in vitro and the activity of this enzyme increased with the increase in age of the culture. F. oxysporum f. sp. lycopersici produced more cellulolytic enzyme than F. solani. The activity of cellulolytic enzyme by F. oxysporum f. sp. lycopersici was more in 14th day-old culture and decreased with the increase of culture age whereas the activity of cellulolytic enzyme produced by F. solani did not decrease and enzyme activity increased with the increase in the age of culture (23rd day-old culture). In vitro efficacy of systemic fungicides viz., Roco (Thiophanate methyl 70% WP) and Chlorothalonil (non-systemic fungicide), herbicides viz., Syncore (Metribuzin 70% WP), 2, 4- D (2, 4- Dichlorophenoxy acetic acid) and insecticides viz., Nuvan (Dichlorvos 76% EC), Prima (Acetamiprid 20% SP) against F. solani and F. oxysporum f. sp. lycopersici were evaluated using poisoned food technique at 100, 200, 400 ppm concentrations on 7th day of inoculation. The fungicide (Chlorothalonil) inhibited the mycelial growth of F. solani by 82.34%, while Thiophanate methyl inhibited F. oxysporum f. sp. lycopersici by 77.96% respectively at 400 ppm concentration. Herbicide (Metribuzin) inhibited the mycelial growth of F. oxysporum f. sp. lycopersici and F. solani by 75% and 62.50%, respectively at same concentration followed by insecticides Dichlorvos (56.87%) and Acetamiprid (53.12%), respectively.
Shivali Sharma, K. Kumar and Amit Kumar

Department of Fruit Science, UHF, Nauni-Solan (Himachal Pradesh), Division of Fruit Science, SKUAST-Jammu, India.

Key words: Growth, divergence, exotic cultivars, local selections, walnut germplasm

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 66-69.

Abstract: Exotic cultivars introduced from abroad and local selections from seedling population of walnut were subjected to Non-hierarchical Euclidean cluster analysis based on 12 nut and kernel characters. Studied accessions were grouped into four clusters, where cluster 1 and 3 had majority of the accessions. The clustering pattern of walnut genotypes belonging to the same eco-geographical region revealed their distribution in more than one cluster showing between geographic and genetic diversity. The first component presented maximum eigen root value and per cent variation. The mean intra and inter cluster distance (D) revealed that cluster 4 had highest intra cluster distance (2.206), while the inter cluster distance was maximum between cluster 3 and 4 (5.806). Maximum mean nut yield, nut length, nut weight and kernel weight was recorded in cluster 4, whereas, maximum kernel percentage and fat percentage was recorded in cluster 1 and 2, respectively. Minimum shell thickness was observed in cluster 2. The accessions of cluster 3 and 4 were found highly diverse from each other and will give better segregants after hybridization which can be used as a parent in further breeding programme.
Srilatha Vasanthu, K. Sunil Kumar, B. Padmodaya and C. Kiran Kumar Reddy

KVK, ANGR Agricultural University, Utukur, Kadapa, Andhra Pradesh-516003. ARS, ANGR Agricultural University, Utukur, Kadapa Andhra Pradesh-516003

Key words: Papaya, boron deficiency, leaf boron, deformed fruits and yield

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 70-75.

Abstract: Boron deficiency in papaya causes deformation of apical meristem, distortion of young leaves, dwarfing of plants, fruit deformities and uneven fruit ripening that severely reduces the yield and quality. Hence, an experiment on effects of foliar application of boron on yield and quality of papaya with a commercially important variety Red lady was conducted at fifteen locations of Andhra Pradesh where the boron deficiency is wide spread due to tropical climate and high soil pH. Foliar application of 0.03 % borax at every 60 days interval from planting to harvest recorded significant increase in the leaf boron content from 18.44 mg kg-1 to 26.62 mg kg-1. Borax application recorded 29 % more number of fruits per plant, 37 % higher yields (65.28 kg plant-1) and reduced deformed fruits (13.58 %) compared to control (21.34 %). The study clearly indicated that, the regular supply of boron through foliar application in tropical climate is vital for realizing higher yields in papaya.
D. Singh, M.I.S. Gill, R.S. Boora and N.K. Arora

Department of Fruit Science, Punjab Agricultural University, Ludhiana-141004, Punjab. PAU Regional Fruit Research Station, Bahadurgarh, Patiala, Punjab

Key words: Psidium guajava, genetic variability, heritability, genetic advance, correlation

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 76-78.

Abstract: The study was conducted to assess the genetic variability, heritability, genetic advance and correlation coefficient among 35 guava (Psidium guajava L.) genotypes, evaluated for tree, vegetative, reproductive, fruit and seed characters during 2010 to 2013. Wide range of phenotypic variability in the studied material was observed as phenotypic coefficients of variation for different traits ranged from 8.17 for fruit width to 35.00 for number of seeds per fruit. Genotypic coefficient of variation for all the characters ranged from 6.95 to 33.11 percent. Heritability ranged from 73.97 to 99.77 percent. Very high heritability estimates were obtained for fruit length to width ratio. The genetic advance as per cent of mean was highest for number of seeds per fruit (64.52 %). Characters like seed weight per 100 g fruit, seed weight per fruit, 100-seed weight, thickness of outer flesh and fruit weight had high heritability and higher genetic advance, which indicate that the expression of these characters is governed by additive gene action. Genotypic correlation coefficients, in general, were higher in magnitude than the corresponding phenotypic correlation coefficients indicating an inherent association among various characters under study. Presence of genetic variability along with high heritability and genetic advance indicate that these genotypes can be further utilized in guava breeding programme, keeping in mind the inherent association of various agronomical important traits to combine the desired traits into a single line/cultivar.
Angrej Ali and B.P. Singh

Department of Horticulture, Narendra Deva University of Agriculture and Technology, Narendra Nagar, Kumarganj, Faizabad, Uttar Pradesh-224 229 (India).

Key words: Cape gooseberry, crop residue, NPK fertilizers, Physalis peruviana L., plant spacing, soil properties

Journal of Applied Horticulture, 2015, volume 17, issue 1, pages 79-84.

Abstract: The cape gooseberry (Physalis peruviana L.), a quick growing herbaceous crop, leaves behind a good amount of crop residue in the field after fruit harvest that can be utilized as organic source of plant nutrient supply to next crop to be cultivated. In present investigation, crop residue of cape gooseberry grown in sodic soil of Eastern Uttar Pradesh (India) at three planting density (S1 - 75 x 60 cm, S2 - 75 x 75 cm and S3 - 90 x 75 cm) and four levels of NPK fertilizers (F0 - without fertilizers, F1 - 60:40:40, F2 - 80:60:60 and F3 - 100:80:80 NPK kg ha) was estimated. Soil properties were also studied before and after cropping seasons. Mean data of two consecutive years recorded crop residue (fresh biomass) production 34.51, 29.7 and 27.95 t ha-1 at S1, S2 and S3 plant spacing, respectively. The application of NPK fertilizers significantly increased crop residue production and mean value recorded with fertilizer level F0, F1, F2, and F3 was 22.00, 28.71, 34.24 and 36.63 t ha-1, respectively. Increased plant population per unit area as well as higher doses of NPK levels showed a little improvement in bulk density, porosity, organic carbon, pH and EC of soil but influence was non-significant, however, plant spacing and NPK fertilizer treatments exhibited significant improvement in available nitrogen, phosphorus and potassium of the soil at the end of the second cropping season.
Andrew G. Reynolds and Javad Hakimi Rezaei

Cool Climate Oenology and Viticulture Institute, Brock University, St. Catharines, ON, Canada L2S 3A1.

Key words: Global positioning systems, geographic information systems, precision viticulture, soil moisture, leaf water potential

Journal of Applied Horticulture, 2014, volume 16, issue 3, pages 167-192 .

Abstract: The possible influence of vine water status upon berry composition was studied in ten commercial vineyard blocks of Vitis vinifera L. cv. Cabernet franc in the Niagara Peninsula, Ontario from 2005 to 2007. Soil texture, soil chemical composition, soil moisture and leaf water potential (?), as an indicator of vine water status, were determined on ? 80 sentinel vines in each vineyard. In each block, water status zones were identified in GIS-generated maps using leaf ? and soil moisture measurements. Areas of low soil and vine water status were positively correlated linearly and spatially with areas of high Brix, color intensity, anthocyanins and phenols, and were negatively correlated with titratable acidity. In most vineyards, areas of high and low color intensity were positively correlated linearly and spatially with areas of high and low anthocyanins and phenols. Temporal stability was also noticeable for several variables including soil moisture, yield, berry weight, Brix, anthocyanins, and phenols. These data suggest that low soil moisture and low vine water status zones in vineyards are related to corresponding areas of superior berry composition. These data further suggest that precision viticulture techniques may be utilized in this region to delineate vineyard sub-zones of differing quality levels.
Kathryn Kamo, Kanniah Rajasekaran and Jeffrey Cary

Floral and Nursery Plants Research Unit, U.S. National Arboretum, U.S. Department of Agriculture, Bldg. 010A, Beltsville, MD 20705-2350, USA. Food and Feed Safety Research Unit, U.S. Department of Agriculture, Southern Regional Research Center, New Orle

Key words: Flower bulbs, biolistics, transgenes, regeneration, tissue culture, corms, ornamentals, gene gun bombardment, callus

Journal of Applied Horticulture, 2014, volume 16, issue 3, pages 193-198 .

Abstract: The growth characteristics of transgenic Gladiolus plants cvs. ´┐ŻPeter Pears´┐Ż and ´┐ŻJenny Lee´┐Ż were compared to non-transformed plants either regenerated from embryogenic callus or micropropagated in vitro. Micropropagated and regenerated plants of ´┐ŻPeter Pears´┐Ż showed similar sprouting percentage of corms in vitro and daughter corm production after one season in the greenhouse. Differences were found in the weight of corms produced in vitro and the length of leaves with the regenerated corms weighing less and having shorter leaves than those of micropropagated plants. Transgenic plants of ´┐ŻPeter Pears´┐Ż had similar corm weights to those from regenerated plants, but the greenhouse sprouting percentage, leaf length, and daughter corm production was less than that of regenerated plants. Micropropagated plants of ´┐ŻJenny Lee´┐Ż were similar to regenerated plants in weight of corms grown in vitro, sprouting efficiencies, and the length of leaves. Transgenic plants of ´┐ŻJenny Lee´┐Ż produced larger corms in vitro than regenerated plants, and both the final weight of transgenic corms and leaf length after one season in the greenhouse were comparable to that of regenerated plants of ´┐ŻJenny Lee´┐Ż. ´┐ŻJenny Lee´┐Ż plants were less affected by the regeneration and transformation conditions than ´┐ŻPeter Pears´┐Ż.
V.P. Sosa-Flores, F. RamÝrez-Godina, A. Benavides-Mendoza, H. RamÝrez

Departamento de Horticultura, Departamento de Fitomejoramiento, Universidad Autˇnoma Agraria Antonio Narro, Buenavista, Saltillo, Coahuila, C. P. 25315, MÚxico.

Key words: Irradiance, photoreceptors, signaling, seed irradiation, seed priming, Cucumis melo.

Journal of Applied Horticulture, 2014, volume 16, issue 3, pages 199-204 .

Abstract: It is well known that exposure of plant seedlings or plants to UV-B radiation induces changes in gene expression resulting in biochemical and morphological modifications. However, there is little information on the effects and potential utility of irradiation of seeds with UV-B. The aim of this study was to apply UV-B radiation in melon seeds using various irradiation times and then assess the effect on growth and morphology of the plant. Seeds of cultivar ĹTopmarkĺ were exposed to UV irradiation with wavelength centered at 302 nm, for periods of 0, 15, 30 and 45 minutes (UV dosages of 0, 99, 198 and 297 mJ cm-2, respectively). The irradiated seeds were seeded in a mixture of peat moss and perlite for greenhouse germination. Morphological parameters such as plant height, stem diameter, number of leaves, leaf area, fresh and dry weights were evaluated. Stomatal frequency, stomatal index, and length and width of stomata were studied. Histological analyses were conducted to determine the areas of the stem vascular bundle and xylem vessels, width and length of vascular bundles, and the area of the lumen of xylem vessels. The analysis of variance indicated significant differences between treatments, with the treatment of 15 minutes (99 mJ cm-2) of seed exposure to UV-B radiation generating 24.87 and 32.42 % more fresh and dry weight of the plants, respectively. Stomatal index was augmented on the adaxial surface by 52.26, 7.14 and 13.55 %, in the treatments of 99, 198 and 297 mJ cm-2, respectively, in contrast with the control treatment, while the length of stomata was increased by 6.99% in the treatment with 30 minutes exposure time (198 mJ cm-2). Stomatal frequency was unchanged by exposure to radiation. The irradiation of the seeds caused decrease in P, Ca and Na in the leaves of plants.
Yun-wen Wang, Bruce L. Dunn, Li Jiang and Daryl B. Arnall

Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing 100193, The People´┐Żs Republic of China. Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater OK 740

Key words: Euphorbia pulcherrima, NDVI, bract colour, greenhouse

Journal of Applied Horticulture, 2014, volume 16, issue 3, pages 205-209 .

Abstract: Normalized difference vegetative index (NDVI) values are vegetative indices, calculated from active canopy sensor measurements using the reflectance values for red and near-infrared. Use of NDVI sensors offers the possibility of rapid, non-destructive readings that correlate with plant properties such as plant biomass and plant nutrition when plants are green, however, the affects of color on NDVI sensor readings has not be investigated. Poinsettia cultivars ´┐ŻEnduring Marble´┐Ż, ´┐ŻIce Punch´┐Ż, ´┐ŻWinter Rose Early Red´┐Ż, ´┐ŻPrestige Red´┐Ż, ´┐ŻPrestige Maroon´┐Ż, ´┐ŻPeterstar White´┐Ż, ´┐ŻMaren´┐Ż, and ´┐ŻOrange Spice´┐Ż were analyzed by an NDVI sensor starting four weeks after transplanting and through bract color development. The results indicated that cultivar effect, time effect and the interaction of cultivar and time on NDVI value were significant (P < 0.0001). An increase of NDVI value occurred from initial measuring date, and reached the greatest value (ranged from 0.718 to 0.837) between week 6 and week 7 for all cultivars except ´┐ŻOrange Spice´┐Ż and ´┐ŻWinter Rose Early Red´┐Ż. From the peak readings, all NDVI values in tested cultivars declined significantly, especially after bract coloration. This result demonstrated an inverse relationship with increased bract coloration and reduced NDVI readings, so use of NDVI readings to detect N deficiencies should be before bract coloration in poinsettias. However, the NDVI sensor could be used to monitor bract colour development. Because the effects of cultivar, time, and the interaction between cultivar and time were significant, standards using a pocket NDVI sensor in specific cultivars during determined growth stages may need to be established at each growing facility.

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