No abstract

Citrus rinds contain a tremendous amount of essential oils. The peels contain majority of the essential oils that are continuously wasted. One of the major constituents of the essential oils in the zest of different citrus fruits like orange, tangerine, lemon and grapefruit is limonene. The review aims at discussing various conventional and novel extraction methods of limonene from citrus fruits. The review also discusses various therapeutic properties of limonene and the mechanism behind these properties. Limitations in the use of limonene such as toxicity and side-effects will be delineated. Limonene is present in the range of 26.9-97.83% in the citrus essential oils. The percentage of limonene in the essential oil depends on the Citrus species and extraction methodology. There are different extraction methods such as hydrodistillation, steam distillation, cold pressing, microwave-assisted extraction, ultrasound sound assisted extraction and supercritical fluid extraction. Various therapeutic potential of limonene has been reported. Limonene is usually non-toxic but its epoxides can be toxic at the very high dose. This up to date and comprehensive review aims to provide a valuable overview of limonene and its therapeutic potential.

Tagetes is a genus of annual, perennial or herbaceous plant in the family Asteraceae. Most of the species have pinnate green leaves. Blooms are naturally occurring in golden, orangeyellow, and white colour, often with maroon highlights. Floral heads are 4 to 6 cm in diameter, generally with both ray florets and disc florets. The present study was conducted at the post graduate research laboratory at Department of Horticulture, Faculty of Agriculture, Annamalai University to find out the “Effect of plant growth regulators on flowering and yield of African marigold (Tagetes erecta Linn)”. The experiment was laid out in Randomized Block Design with three replications. There were ten treatments, viz., GA3 100 ppm, GA3 200 ppm and GA3 300 ppm, NAA 100 ppm, NAA 200 ppm, NAA 300 ppm, Ethrel 50 ppm, Ethrel 100 ppm, and Ethrel 150 ppm and control. Among the growth regulators tried, GA3 200 ppm as foliar application on 30 and 60 days after transplanting registered the highest values for plant characters like plant height (47.1 cm), number of branches ( 35.1), days taken to first flower bud appearance (39.3 days), days taken to flower opening (37.6 days), longevity of flower (11.17 days), stalk length (12.1 cm), diameter of flower (7.8 cm), number of flowers per plant (40.3), weight of the single flower (9.1 g), yield of flowers per plant (337 g) and flower yield per plot (11.1 kg). From the present study, it is recommended that spraying of GA3 200 ppm on 30 and 60 days after transplanting improved yield and quality of African marigold flowers.

Potassium is involved in a diverse range of processes within plants that are needed for their growth, yield and better quality. The polyhalite as a hydrated evaporate mineral that can be used directly as a source of potassic fertilizer. However, research on polyhalite's appropriateness and effectiveness, the present investigation aimed to evaluate the effect of polyhalite on growth, yield attributes, and yield of blackgram variety ADT 5 at Chinnakandiankuppam village, Vriddhachalam, Cuddalore district, Tamil Nadu, during 2021. The experiment was laid out in randomized block design consisting of ten treatments viz., T1 (absolute control), T2 (-K), T3 (12.5 kg K2O ha-1 as muriate of potash (MOP)), T4 (25 kg K2O ha-1as MOP), T5 (37.5 kg K2O ha-1 as MOP), T6 (50 kg K2O ha-1 as MOP), T7 (12.5 kg K2O ha-1 as polyhalite),  T8 (25 kg K2O ha-1 as polyhalite), T9 (37.5 kg K2O ha-1 as polyhalite), T10 (50 kg K2O ha-1 as polyhalite). The experiment revealed that the application of 37.5 kg K2O ha-1 as polyhalite (T9) significantly (5%) enhanced the growth attributes (plant height (38.7 cm), number of branches plant-1 (12.97), leaf area index (2.13), number of nodules plant-1 (18.76) and dry matter production (1972 hg ha-1), yield attributes (pod length (8.21 cm), number of pods plant-1 (20.05), number of seeds pod-1 (7.14) and test weight (3.53 g)) and grain yield (1439 kg ha-1), haulm yield (1876 kg ha-1) of blackgram. Thus the study would be helpful to farmers for yield maximization of blackgram through polyhalite as potassic fertilizer.

Tamilnadu is one of the leading states in rice production in India. Weeds are widely found and are tremendously grown everywhere on paddy fields. Ethnobotany have gained importance during recent years. Based on this, an ethnobotanical exploration has been carried to find out the medicinal values of weed plants growing in the paddy fields of Annamalai Nagar, Cuddalore district. The study reveals the importance of the weed plants associated with paddy fields, a total of 40 species of weeds belonging to 22 families has been recorded in meeting the multiple requirements of human beings.