scholarly journals A SEASON EXTENSION TECHNIQUE FOR COOL SEASON VEGETABLES USING POLY TUNNELS AND ROW COVERS

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 269E-269
Author(s):  
Gloria McIntosh ◽  
Gerald Klingaman

Spunbonded polyester or polystyrene row covers were used as additional cold protection for spinach (Spinacia oleracea), kale (Brassica oleracea), pak choi (Brassica rapa) and P-types of lettuce (Lactuca savita) grown in ground beds under unheated polyethylene tunnels during the fall and winter of 1991 and 1992 in climatic zone 6. Temperatures inside poly tunnels averaged 2.4C warmer than outside. Average temperatures were 1.9C warmer than control under polystyrene and 1.5C warmer under spunbonded polyester. Average hourly temperatures showed both row covers offered significantly more cold protection than the greenhouse covering alone; but the two row covers offered similar protection from the cold. Row covers did not result in fresh weight differences in most of the species tested, except kale which had greater fresh weight in control. It may be concluded that during a similar mild winter, these cool season vegetables could be grown under unheated polyethylene tunnels with no additional protection necessary. When temperatures are lower, row covers could provide the protection required to produce these crops.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 480e-480
Author(s):  
Nancy H. Furness ◽  
Mahesh K. Upadhyaya ◽  
Douglas P. Ormrod

Relative sensitivity of selected vegetable and weed seedlings to ultraviolet-B (UV-B) radiation (280–320 nm) was investigated. Seedlings were grown for 4 weeks in a greenhouse, in chambers equipped with UV-B-emitting fluorescent tubes and Mylar (control) and cellulose acetate (UV-B) filters. UV-B radiation reduced seedling height, leaf area, and leaf fresh weight in tomato (Lycopersicon esculentum `Cour Di Bue'), broccoli (Brassica oleracea var. Italica `Purple Sprouting'), cabbage (Brassica oleracea var. Capitata `Red Drumhead'), and cucumber (Cucumis sativus `Straight Eight'), leaf area and leaf fresh weight in beet (Beta vulgaris `Cylindra' and `Early Wonder'), seedling height and leaf area in spinach (Spinacia oleracea `Long Standing Bloomsdale'), lettuce (Lactuca sativa ``Red Salad Bowl Everest') and `Savoy' cabbage, and seedling height in `Chinese Tip Top' cabbage and lettuce (`Saladin'). `Winterton' cabbage was not affected. UV-B radiation decreased leaf area and leaf fresh weight in common chickweed (Stellaria media) and corn spurry (Spergula arvensis) and seedling height in green foxtail (Setaria viridis) and redroot pigweed (Amaranthus retroflexus). Tillering was stimulated in response to UV-B in green foxtail. There was no effect of UV-B on lady's-thumb (Polygonum persicaria) growth. Leaf number was not affected by exposure to UV-B in any species. The differential morphological sensitivity of vegetable and weed seedlings may result in altered competitive relationships under enhanced UV-B levels expected with the depletion of the earth's ozone layer.


1987 ◽  
Vol 59 (5) ◽  
pp. 425-430
Author(s):  
Seija Ahonen ◽  
Iris Kuokkanen ◽  
Pirjo-Liisa Penttilä

Nitrate concentration of some domestic vegetables at Helsinki district market was studied during the summer and autumn months of the year 1984.The species were cabbage (Brassica oleracea var capitata), Chinese cabbage (Brassica pekinensis), kohlrabi (Brassica oleracea var gongylodes), turnip (Brassica rapa), carrot (Daucus Carola subsp. sativas) and crisphead and butter head lettuce (Lactuca saliva var. capitata). The 395 samples were analysed with an ion specific electrode. There was a wide range of nitrate concentrations within each species. The mean concentrations mg nitrates/kg of fresh weight were the following: butter head lettuce 1835, Chinese cabbage 1057, kohlrabi 1008, crisphead lettuce 964, turnip 908, cabbage 607 and carrot 264. The nitrate concentration of butter head lettuce in the autumn was more than twice as high as that in the summer, and vice versa as to cabbage samples. The nitrate concentration of carrot samples in the summer was about 40 % higher than in the autumn.


AGRICA ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 131-141
Author(s):  
Emilia S.A. Wangge ◽  
Imanuel Sedi Benu

This study aims at determining the impact of planting distance on the growth and yield of Pak Choy and determining the optimal distance that can optimize the growth and yield of Pak Choi.  This study employed group random design with 6 treatments of planting distance, namelyJ1 = 20 cm x 25 cm, J2 = 20 cm x 20 cm, J3 = Planting distance 20 cm x 15 cm, J4 = Planting distance 20 cm x 10 cm, J5 = 10 cm x 15 cm, J6 = 10 cm x 10 cm.Each treatment was repeated 4 times so that there were 24 specimen garden-beds. It is found out that planting distance did not have any impact on plant height, the width of leaves, and numbers of leaves at age of 10–20 days after planting, whereas there was an impact on plant age of 25–35 days after planting on plant height of 15.59 cm, a number of leaves of 9.17 cm, the width of leaves of 52.28 cm and fresh Pak Choy weight of 148.4g per plant, fresh weight per ha 1204.43 ha.


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1023C-1023
Author(s):  
Lurline Marsh ◽  
Corrie Cotton ◽  
Elizabeth Philip ◽  
Salina Parveen ◽  
Fawzy Hashem

Excessive amounts of poultry waste on the Delmarva Peninsula of the United States, coupled with the availability of yard waste, may be potential inexpensive nutrient sources for growing vegetables. However, these composts may contain unsafe microorganisms. This study, therefore, was conducted to determine the presence and persistence of biological agents in soil treated with poultry compost and yard waste. Tatsoi [Brassica rapa (Narinosa Group)] and spinach (Spinacia oleracea L. `F415' and `Seven R') were planted under a high tunnel to extend their fall growing season. Samples of soil–compost mixture and original poultry compost were collected once a month for 4 months. Escherichia coli O157:H7 in the samples was determined by enrichment and immunomagnetic separation, and was not detected in any of the soil-mixtures. However, this bacterium was detected in the original poultry compost in very low numbers. Plant leaves were harvested periodically. Results showed that tatsoi plants significantly produced larger leaves and higher fresh weight in soils amended with organic compost with the tendency for yield to increase with the increase in harvest date. Generally, the organic amendments did not influence size and total fresh weight of spinach leaves, although earlier harvests tended to produce significantly larger leaves and higher fresh weight.


Author(s):  
Santosh Shiwakoti, Valtcho D. Zheljazkov ◽  
Vicki Schlegel

Plastic tunnels are the viable options for the successful production of cold-tolerant vegetables during cold months of the milder climate regions. However, growing vegetables in northern climates can be a challenge because of long and severe winters. Therefore, we conducted a plastic tunnels study on carrot, radish, spinach, and pak choi in northern Wyoming, USA to explore the viability and quality of the vegetable production under winter stress. The objective was to quantify the effect of different season extension methods on the produce yield, its total phenol content, and antioxidant activity. The experiment consisted of three tunnel systems: high tunnel (Ht), low tunnel (Lt), and low tunnel within high tunnel (LtHt). We were able to harvest vegetables in the freezing November of Wyoming. Spinach, and pak choi had markedly higher yield in LtHt (6,410 kg ha-1 spinach and 20,644 kg ha-1 pak choi) than Ht (4,574 kg ha-1 for spinach and 12,076 kg ha-1 for pak choi) and Lt (3,253 kg ha-1 spinach and 8,242 kg ha-1 pak choi).  The concentrations of nutrients in the vegetables weren’t affected by the tunnel systems. Greater antioxidant activity of pak choi was evident in Ht than in Lt and LtHt. This experiment demonstrated that challenges of severe winter for growing cool-season vegetables can be mitigated largely by opting for LtHt rather than Lt or Ht alone.


HortScience ◽  
1999 ◽  
Vol 34 (4) ◽  
pp. 696-699 ◽  
Author(s):  
Charles F. Forney ◽  
Michael A. Jordan

Methanethiol (MT) is a volatile compound responsible for the unpleasant odor evolved when fresh broccoli (Brassica oleracea L., Italica group) is held under anaerobic conditions. Inductive atmospheres can develop in storage, transportation containers, or modified atmosphere packages, resulting in reduced quality. To determine if related vegetables are capable of producing MT, 12 different vegetables from the genus Brassica were cut into ready-to-eat forms. Fifty-gram samples were sealed in 500-mL glass jars and flushed with N2. After 24 h in the dark at 20 °C, headspace samples from the jars were analyzed for MT and other volatiles. Headspace concentration of MT was greatest in broccoli florets, followed by pak choi (Brassica rapa L., Chinensis group) leaf blades, savoy cabbage (Brassica oleracea L., Capitata group), broccoflower (Brassica oleracea L., Botrytis group), and green and red cabbage (Brassica oleracea L., Capitata group). Broccoli stems, kale (Brassica oleracea L., Acephala group), Brussels sprouts (Brassica oleracea L., Gemmifera group), pak choi petioles, rutabaga (Brassica napus L., Napobrassica group) root, cauliflower (Brassica oleracea L., Botrytis group) florets, Chinese cabbage (Brassica rapa L., Pekinensis group), and kohlrabi (Brassica oleracea L., Gongylodes group) tubers produced <3% of the MT produced by broccoli florets. Green tissues appeared to have a greater capacity to produce MT than nongreen tissues. Anaerobic production of CO2 and ethanol did not relate to the vegetable's ability to produce MT. The production of dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) were also induced by the anaerobic conditions. Green cabbage produced the greatest concentration of DMDS, followed by savoy cabbage and broccoli florets. Production of DMTS was similar to the pattern observed for MT, but DMDS production was not highly correlated with MT production.


2010 ◽  
Vol 36 (8) ◽  
pp. 1280-1285 ◽  
Author(s):  
Jun LI ◽  
Li-Xia LUO ◽  
Zhuan WANG ◽  
Jun LI ◽  
Kun-Rong CHEN ◽  
...  

2021 ◽  
Vol 64 (1) ◽  
Author(s):  
Hyeon Ji Yeo ◽  
Seung-A Baek ◽  
Ramaraj Sathasivam ◽  
Jae Kwang Kim ◽  
Sang Un Park

AbstractThis study aimed to comprehensively analyze primary and secondary metabolites of three different-colored (white, pale green, and green) pak choi cultivars (Brassica rapa subsp. chinensis) using gas chromatography attached with time-of-flight mass spectrometry (GC-TOFMS) and high-performance liquid chromatography (HPLC). In total, 53 primary metabolites were identified and subjected to partial least-squares discriminant analysis. The result revealed a significant difference in the primary and secondary metabolites between the three pak choi cultivars. In addition, 49 hydrophilic metabolites were detected in different cultivars. Total phenolic and glucosinolate contents were highest in the pale green and green cultivars, respectively, whereas total carotenoid and chlorophyll contents were highest in the white cultivar. Superoxide dismutase activity, 2,2-diphenyl-1-picrylhydraz scavenging, and reducing power were slightly increased in the white, pale green, and green cultivars, respectively. In addition, a negative correlation between pigments and phenylpropanoids was discovered by metabolite correlation analysis. This approach will provide useful information for the development of strategies to enhance the biosynthesis of phenolics, glucosinolates, carotenoids, and chlorophyll, and to improve antioxidant activity in pak choi cultivars. In addition, this study supports the use of HPLC and GC-TOFMS-based metabolite profiling to explore differences in pak choi cultivars.


2018 ◽  
Vol 20 (1) ◽  
pp. 93
Author(s):  
Jin Wang ◽  
Feiyi Huang ◽  
Xiong You ◽  
Xilin Hou

In plants, heptahelical proteins (HHPs) have been shown to respond to a variety of abiotic stresses, including cold stress. Up to the present, the regulation mechanism of HHP5 under low temperature stress remains unclear. In this study, BcHHP5 was isolated from Pak-choi (Brassica rapa ssp. chinensis cv. Suzhouqing). Sequence analysis and phylogenetic analysis indicated that BcHHP5 in Pak-choi is similar to AtHHP5 in Arabidopsis thaliana. Structure analysis showed that the structure of the BcHHP5 protein is relatively stable and highly conservative. Subcellular localization indicated that BcHHP5 was localized on the cell membrane and nuclear membrane. Furthermore, real-time quantitative polymerase chain reaction (RT-qPCR) analysis showed that BcHHP5 was induced to express by cold and other abiotic stresses. In Pak-choi, BcHHP5-silenced assay, inhibiting the action of endogenous BcHHP5, indicated that BcHHP5-silenced might have a negative effect on cold tolerance, which was further confirmed. All of these results indicate that BcHHP5 might play a role in abiotic response. This work can serve as a reference for the functional analysis of other cold-related proteins from Pak-choi in the future.


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