Papers by Usha Palaniswamy
Effects of nitrate: ammonium nitrogen ratio on the oxalate level of purslane
to yield NO 3 - -N: NH 4 + -N ratios of 1:0, 0.75:0.25, 0.5:0.5, and 0.25:0.75. The solutions als... more to yield NO 3 - -N: NH 4 + -N ratios of 1:0, 0.75:0.25, 0.5:0.5, and 0.25:0.75. The solutions also contained macronutrients (in µg mL -1 ) 31 P, 207 K, 200 Ca, 48 Mg, and 64 S and the micronutrients (in µM) 2 Na, 50 Cl, 25 B, 2 Mn, 2 Zn, 0.5 Cu, 0.5 Mo and 50 FeEDTA. The nutrient solutions in the hydroponic systems were aerated for 1 min every 30 min using a time-controlled air bubbler. The solution pH was monitored at 4 d intervals and maintained at 6.6 to 6.8 by adding 0.5 M HCl or NaOH as needed. Treatments were arranged in randomized complete blocks design with five replications. There were six plants in each treatment replication.
INTRODUCTION Curry leaf (Murraya koenigii Spreng., Rutaceae), is a popular leafy-spice used in As... more INTRODUCTION Curry leaf (Murraya koenigii Spreng., Rutaceae), is a popular leafy-spice used in Asian-Indian cuisine for its characterizing authentic flavor and distinct aroma (Fig. 1). The curry leaf is used by Asian Americans originating from South Asia almost daily in its fresh form when available and is preserved as dried or frozen for long-term storage. Interest in greater use of curry leaf has been stimulated since its high antioxidant and anticarcinogenic potential were reported (Khan et al. 1997; Khanum et al. 2000), as well as the changing demographics nationwide that have created a ready market and greater demand for this spice (Palaniswamy 2001). Curry leaf is used in very small quantities for its distinct aroma due to the presence of volatile oils and as a result most studies report on the concentrations of volatile oils and not on the nutritional value and functional properties attributed to antioxidant vitamins and plant pigments. The objective of this study was to eval...
INTRODUCTION Purslane (Portulaca oleracea L., Portulacaceae) is eaten extensively as a potherb, a... more INTRODUCTION Purslane (Portulaca oleracea L., Portulacaceae) is eaten extensively as a potherb, and added in soups and salads around the Mediterranean and tropical Asian countries (Fig. 1). There is a newer interest in cultivation of purslane as a crop since its identification as one of the best sources in the plant world for omega-3 fatty acid, α-linolenic acid (LNA). LNA is a precursor of a specific group of hormones (prostaglandins) and may offer protection against cardiovascular disease, cancers and a number of chronic diseases and conditions throughout the human life. Research indicates that omega-3 fatty acids will eventually receive the attention and broad recommendations now given to fiber (Philipson et al. 1985). Purslane is also reported as an excellent source of the antioxidant vitamins α-tocopherol, ascorbic acid, and β-carotene as well as glutathione, and the amino acids isoleucine, leucine, lysine, methionine, cystine, phenylalanine, tyrosine, threonine, and valine (Mi...
Effects of storage temperature on the nutritive value of curry leaf
HortTechnology
There is an amazing variety of Asian vegetables that, even today, are largely unknown in the Unit... more There is an amazing variety of Asian vegetables that, even today, are largely unknown in the United States. However, as Asian populations increase in numbers and diversity, local demand has increased and opened up opportunities to identify suitable crops for successful cultivation and possible export of these vegetables back to Asian countries. Production strategies for successful cultivation of Asian vegetable crops include the identification of suitable species; access to genetic material and germplasm collections; evaluation of imported genotypes; development of technologies, skills, and resources to collect production data; monitoring of the risks from pests and diseases; identification of new pests and pest management techniques; and organization of research on postharvest handling, packaging, and transport for a wide range of products to meet the consumer demands.
Introduction to the Workshop
HortTechnology
HortScience
Omega-3 fatty acids (O3FA) are essential for normal human growth, development, and disease preven... more Omega-3 fatty acids (O3FA) are essential for normal human growth, development, and disease prevention. Purslane (Portulaca oleraceae L.) is an excellent source of alpha-linolenic acid (LNA, an O3FA) and the anti-oxidant alpha-tochopherol. Twenty-one-day-old seedlings of cultivated purslane seedlings were transplanted into greenhouse (≈18-20 °C) and arranged in a randomized complete-blocks design with six replications. Plants were fertilized with nitrogen at 25 mg·mL-1 for the first week, 50 mg·mL-1 for the next week, and 100 mg·mL-1 until harvest using a 20N-4.4P-16.6K water-soluble fertilizer in the irrigation water. The terminal three nodes of shoots were harvested at 6, 10, and 14 trueleaf stage. At each harvest the dry mass (DM), fresh mass (FM), and leaf area were determined. The leaf and stem LNA concentration were determined using gas chromatography. The leaf fatty acid concentrations were 30% to 52% higher at the 6- and 14-leaf stages than at 10-leaf stage. The fatty acid co...
Hortscience, Jul 1, 2005
Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to ... more Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to supply germanium to fruit have been carried out since tests have confi rmed germanium's role as a medical substance. Supplying germanium to orchards by soil and foliar application was not effective because of loss from rainfall. Also, tree injection with germanium solution required the insertion of a tube to the tree xylem at each injection site. In order to increase germanium absorption by fruit, this study carried out the postharvest dipping of fruit into germanium solution. 'Niitaka' pear (Pyrus pyrifolia) fruit was treated with two types of germanium, GeO (inorganic type) and Ge-132 (organic type), in a concentration of 50 mg•L-1 just after harvest in early Oct. 2004. Flesh browning after peeling the fruit was delayed by germanium treatment, and polyphenoloxidase (PPO) activities were lowered. Postharvest potentials were maintained at high levels for fruit fi rmness, physiological disorders, and decayed fruit during cold storage at 0 to 1 °C for 2 months. Antioxidant and some phenolic compounds were higher than those of control fruit.
Leaf yield and fatty acid composition of purslane (Portulaca oleracea L.) at different growth stages
Journal of Tropical Agriculture, 2000
Horttechnology, Oct 1, 2001
Enhancement of naturally occurring chemopreventive compounds in salad greens through environmental manipulation during crop growth
Medicinal plants of Asian origin and culture
Journal of the American Society For Horticultural Science, Sep 1, 2001
Portulaca oleracea L.) is an excellent source of the essential fatty acid α α α α α-linolenic aci... more Portulaca oleracea L.) is an excellent source of the essential fatty acid α α α α α-linolenic acid (LNA) but little is known of the effects of cultural conditions on LNA concentration. Purslane seedlings were grown under an instantaneous photosynthetic photon flux [PPF (400 to 700 nm)] of 299 or 455 µmol•m-2 •s-1 for a daily duration of either 8, 12, 16, or 20 hours. Thus, plants were exposed to a daily PPF of 8.6, 12.9, 17.2, or 21.5 mol•m-2 •d-1 in the low PPF treatment (299 µmol. m-2. s-1) and 13.1, 19.7, 26.2, or 32.8 mol•m-2 •d-1 in the high PPF treatment (455 µmol•m-2 •s-1). Plants in all treatments received a 20-hour photoperiod by providing ≈5 µmol•m-2 •s-1 from incandescent lamps starting at the end of the photosynthetic light period. At low PPF, purslane grown under a 16 hour PPF duration produced the highest concentrations of total fatty acids (TFA) and LNA per unit leaf dry weight (DW), but at high PPF, concentrations of these compounds were highest under 8 and 12 hour PPF duration. Trend analysis indicated that maximum TFA and LNA concentrations occurred with a daily PPF of 14.1 and 17.2 mol•m-2 •d-1 , respectively; and in the thylakoids, protein, chlorophyll, and LNA concentrations peaked at a PPF of 21.8, 19.9, and 16.1 mol•m-2 •d-1 , respectively. LNA as a percentage of TFA was unaffected by treatment. Shoot DW increased with PPF up to the highest PPF exposure of 32.8 mol•m-2 •d-1. ing increase in chlorophyll biosynthesis and LNA biosynthesis in Japanese morning glory (Pharbitis nil Choisy) (Tchang et al., 1985), pea (Pisum sativum L.) (Tremolieres, 1972; Tremolieres et al., 1973), and cotyledons of cucumber (Cucumis sativus L.) (Murphy and Stumpf, 1979). Tchang et al. (1985) described the rate of LNA synthesis in Japanese morning glory, as a "function of light and chlorophyll accumulation." Anderson and Beardall (1991) declared a "synchronized synthesis of chlorophyll, fatty acids and proteins for the correct assembly of lipids and proteins" for the formation of uniform lamellar bilayers of the thylakoid membranes in plants. Therefore, the objectives of this study were to examine effects of total daily PPF delivered under various combinations of irradiance and duration on growth, chlorophyll, and fatty acid concentrations, and to determine the environmental conditions that would maximize LNA in purslane leaves. Materials and Methods PLANT MATERIAL. Fourteen-day-old purslane seedlings (Valley Seed Service, Fresno, Calif.) were transplanted into 500-cm 3 square pots containing the commercial medium Metro 510 (O.M. Scotts, Marysville, Ohio), a mixture of sphagnum peat, vermiculite, and composted pine bark. Thirty-two pots were transferred to each of four growth chambers (model G-10; Environmental Growth Chambers, Chagrin Falls, Ohio), equipped with cool-white fluorescent/ incandescent light, programmed to maintain 12-h days/12-h nights of 27/22 °C. PLANT GROWTH ENVIRONMENT. Within each chamber, plants were arranged at two levels, so that 16 plants received an average instantaneous PPF (400 to 700 nm) of 455 µmol•m-2 •s-1 , and the other 16 plants received an average PPF of 299 µmol•m-2 •s-1. Plants were grown under a PPF of 299 or 455 µmol•m-2 •s-1 for a daily duration of either 8, 12, 16, or 20 h. Total cumulative PPF received by the plants per day was 8.6, 12.9, 17.2, or 21.5 mol•m-2 for low PPF (299 µmol•m-2 •s-1), and 13.1, 19.7, 26.2, or 32.8 mol•m-2 for high PPF (455 µmol•m-2 •s-1). The daily photoperiod was maintained at 20 h for all treatments by providing ≈5 µmol•m-2 •s-1 from incandescent lamps starting at the end of the photosynthetic light
Hortscience, Jun 1, 2000
Prune (Prunus domestica) producers have an increased incentive to produce larger fruit. Potassium... more Prune (Prunus domestica) producers have an increased incentive to produce larger fruit. Potassium is thought to be critical in prune production and the fruit utilize large amounts of K. Growers have been fertilizing heavily with K to maximize fruit size. We conducted a survey of 16 'French' prune orchards in 1998 and 1999 growing seasons. Low (≈1.0% mid-July) leaf K concentration is associated with leaf chlorosis, early leaf drop and shoot dieback, with symptoms pronounced in the upper canopy, particularly with heavy cropping. The survey orchards were chosen to represent a range of leaf K within and among orchards, and among counties. At harvest, fruit drying ratio, dry yield per tree, and dried fruit size were determined in order to develop relationships between fruit quality and yield, and leaf K over the growing season. To date we have determined the following: 1) spring (May 1998 and April-May 1999) leaf K concentration is correlated with midsummer (mid-July 1998) and early summer (late June 1999) leaf K concentration, respectively; 2) mid-April to mid-May leaf K concentration is being maintained by growers due to thinning and fertilizing, and to light cropping in 1998, at adequate to above adequate levels (2%) that increase through the growing season; 3) no beneficial relationship between fruit size, drying ratio or dry yield has been found with spring or summer (June or mid-July) leaf K concentration above 2%, either when evaluating all surveyed orchards together or as individual orchards.
Horttechnology, Apr 1, 2003
Vegetarianism dates back to a time before recorded history and, as many anthropologists believe, ... more Vegetarianism dates back to a time before recorded history and, as many anthropologists believe, most early humans ate primarily plant foods, being more gatherers than hunters. Human diets may be adopted for a variety of reasons, including political, esthetic, moral, environmental and economic concerns, religious beliefs, and a desire to consume a more healthy diet. A major factor influencing the vegetarianism movement in the present time is primarily associated with better health. Epidemiologic data support the association between high intake of vegetables and fruit and low risk of chronic diseases and provide evidence to the profound and long-term health benefits of a primarily vegetarian diet. Vegetables and fruit are rich sources of nutrients, vitamins, minerals, and dietary fiber as well as biologically active nonnutrient compounds that have a complementary and often multiple mechanisms of actions, including antioxidant, anti-inflammatory, hypoglycemic, hypocholesterolemic, and hypolipidemic properties, and mechanisms that stimulate the human immune system. Because of the critical link established between diet and health, consumers have begun to view food as a means of self-care for health promotion and disease prevention. Functional foods are targeted to address specific health concerns, such as high cholesterol or high blood sugar levels, to obtain a desired health benefit. Functional properties identified in a number of plant species have led to a modern day renaissance for the vegetarian movement.
Hortscience, Jul 1, 2006
Bulgaria is famous for its 330-year-old-tradition in rose oil production, which is based on the K... more Bulgaria is famous for its 330-year-old-tradition in rose oil production, which is based on the Kazanluk rose (Rosa damascena Mill. f. trigintipetala Dieck.). The Bulgarian rose oil (otto) is recognized as the ultimate rose oil. For successful selection and breeding work of oil-bearing roses, information is needed on the variation of morphological and phenological characteristics and essential oil composition of locally available genotypes. We estimated the correlation coefficients between yields and morphological characteristics of 15 genotypes of Bulgarian oil-bearing rose. It was found that rose yields depended mostly on the number of flowers, the number of flower branches per bush, and the weight of individual flowers (r = 0.99, 0.88, and 0.84, respectively). Also, we established correlations between the concentrations of various essential oil constituents of the Bulgarian rose oil. Generally, higher concentration of citronellol + nerol was associated with lower concentration of geraniol and stereo-terpens (r =-0.76 and-0.59, respectively). Also, higher concentration of citronellol + nerol was positively correlated to increased concentration of terpene aldehydes (r = 0.63) and esters (r = 0.48). The geraniol concentration was positively correlated to stearoptenes (r = 0.57). Both morphological characteristics and essential oil constituents should be used for further selection of high-yielding cultivars with desirable essential oil composition.
Archived Reusable Learning Objects From the International Crop Research in the Semi-Arid Tropics (ICRISAT) in Designing Online Teaching and Learning Activities
ABSTRACT
Fatty Acid Concentration in Portulaca oleraceae L. is Altered by Photosynthetic Photon Flux
HortScience, 1998
Purslane (Portulaca oleraceae L.) seedlings were grown under an instantaneous photosynthetic phot... more Purslane (Portulaca oleraceae L.) seedlings were grown under an instantaneous photosynthetic photon flux (PPF) of 299 or 455 μmol·m–2·s–1 for a daily duration of either 8, 12, 16, or 20 h. Thus plants were exposed to a daily PPF of 8.6, 12.9, 17.2, and 21.5 mol·m–2·d–1 in the low PPF treatment (299 μmol·m–2·s–1) and 13.1, 19.7, 26.2, and 32.8 mol·m–2·d–1 in the high PPF treatment (455 μmol·m–2·s–1). All treatments received a 20-h photoperiod using a PPF of ≈5 μmol·m–2·s–1. At low PPF, purslane grown under 16-h PPF duration produced the highest concentration of total fatty acid (TFA), linoleic acid (LA), and linolenic acid (LNA) per unit leaf dry mass (DM) and leaf area; but at high PPF, the concentration of these compounds was highest under 8- and 12-h PPF duration. Trend analysis indicated that maximum TFA, LA, and LNA concentrations occurred with a PPF of 14.1, 16.9 and 17.2 mol·m–2·d–1 respectively; and protein, chlorophyll, and LNA concentrations in thylakoid membranes were maximized at PPF of 21.8, 19.9, and 16.1 mol·m–2·d–1, respectively. LNA as percent of TFA was unaffected by treatment. DM increased with PPF up to the highest PPF exposure of 32.8 mol·m–2·d–1.
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Papers by Usha Palaniswamy