Patchouli (Pogostemon cablin Benth.): botany, agrotechnology and biotechnological aspects

Patchouli (Pogostemon cablin Benth.) is an industrially valued aromatic medicinal plant currently having a huge demand for its essential oil. It is widely used in flavor and fragrance industries as well as in pharmaceuticals. Clonal propagation is therefore obligatory to obtain homogeneous patchouli plants from preferred germplasm in order to meet the global need. At present, farmers are showing keen interest towards its large scale cultivation mainly in the tropical and sub-tropical countries. Understanding the plant biology, chemistry and other uses allows better utilization of any industrial crops. Therefore, the present review discusses on the botany, agronomy and biotechnological aspects of patchouli. Also, the current market demand for patchouli raw material is being reviewed by highlighting the possible exploration of modern techniques in identifying the adulterants to authenticate this herb. This review provides a comprehensive information on both basic and applied aspects of patchouli crop cultivation and management. The applied aspect of patchouli biotechnology allows one to explore the newer potential for various industrial uses and improve the rural economy

Cryopreservation technology for conservation of selected vegetative propagules

Cryopreservation is the science of freezing biological materials and their subsequent storage at very low temperature in liquid nitrogen (-196°C). At such low temperature, metabolic rates are low or completely halted. Recently the need to conserve plant materials has increased tremendously due to extinction. Plants that produce orthodox seeds can be easily stored in the form of desiccated seeds at low temperature being the most convenient method to preserve plant germplasm. However, it is not applicable to crops that do not produce seed (e.g. bananas) or with recalcitrant or intermediate seed. In addition cryopreservation is now recognized as a powerful tool for the preservation of the unique genomic constitution of cultivars, tissue cultured lines and hybrids such as orchids. Various protocols, ranging from conventional slow freezing to the more modern vitrification based protocols have been established and utilized for various plant materials. To date there is still only limited number of plants whereby cryoconservation is readily used mainly because the techniques need to beadapted for each species. Therefore, continued efforts are needed in cryopreservation techniques to develop protocols for a wider range of plants. Conservation of plant germplasm has moved forward from the more costly slow cooling to vitrification based strategies. For effective adoption of the technique, simple reliable method with high regeneration ability has to be established. Our research in various plants has shown selection of plant material to be one of the most important steps in obtaining successful cryopreservation. In addition, different vitrification protocol can influence the success rate as well. This paper will highlight the importance of explant selection and the importance of method selection for successful cryopreservation using some selected crops

Study on karyotype of selected tea clones (Camellia sinensis) in Iran

In order to study karyotype of selected tea clones (Camellia sinensis) in Iran, squash technique was used. Root samples were pretreated with alpha-bromonaphthalene and then were fixed in Farmer solution. It was hydrolyzed by 1 normal of chloridric acid and stained byaceto-iron-haematoxylin. Total chromosome length, long and short arm length, ratio of long to short arm, and centromere index were measured and also numbers of chromosomes were counted. In all genotypes numbers of chromosomes were 2n=30. In table of correlation coefficients, ahigh positive correlation was observed between total length ofchromosome with length of long arm (r=0.987++), total length ofchromosome with length of short arm (r=0.973++), and length of long arm with short arm (r=0.925++), while there was a high negative correlation between the ratio of long to short arm with centromere index (r=-0.990++). Based on the analysis of main components, total length (TL), long arm length (LA), and short arm length (SA) contributed in creation of the first component, and the most contribution is attributed to long arm of chromosome with coefficient of 0.984. Also, in order to create the second component, parameters such aslong arm to short arm ratio (AR) and centromere index (CI) were involved from which centromere indexwith coefficient of 0.837 played the greatest role. The results showed that in terms of %TF statistics G1 and G7 respectively had the most symmetric and asymmetric karyotypes, and in terms of TL,DRL, TL, and L/S statisticsG2 and G7respectively had the most symmetric and asymmetric karyotypes

Simple and efficient in vitro method of storing Dendrobium sw. shavin white protocorm like bodies (PLBs)

In the present study, an efficient and simple in vitro method for storing orchid protocorm like bodies (PLBs) has been developed for Dendrobium Sw. Shavin. PLBs of Dendrobium Shavin White were kept in an empty airtight container without supplementation of any nutrient and stored for up to 135 days under dark condition at different temperatures namely 5, 10, 25 ± 2°C and 30 ± 2°C. The effects of storage period and temperature on the regeneration ability of the stored PLBs were evaluated. The results revealed that PLBs stored for up to135 days at 25 ± 2°C were found to remain unchanged (72%) and recorded higher germination percentage (88) with shoot proliferation ability of 12% after storage. Though, morphologically about 8% of PLBs were found to be brownish green during storage no morphological abnormalities were recorded after 8 weeks of culture. While, storage at 30 ± 2°C only 20% PLBs remained unchanged and 76% of PLBs turned into brownish during the storage which exhibited germination percentage of 16. Though, PLBs showed survival percentage at low temperatures (5 and 10°C), their survival percentages decreased rapidly as the storage duration was increased. The results clearly suggest that PLBs can be stored for only 15 and 75 days at 5 and 10°C respectively. Lower storage temperature of 5°C was not conducive for PLBs because the survival frequency recorded is very low (24) even when stored for a short period (15 days). Thus, PLBs of Dendrobium Shavin White can be stored for up to135 days at 25 ± 2°C. Ability to store PLBs is vital as it can ease the distribution of the propagules to the laboratories and commercial nurseries to facilitate the production of uniform plants. Furthermore, this in vitro storage method can reduce the need for frequent subculture cycles and conserve the genetic uniformity in germplasm

A study on the use of organic additives on the protocorm-like bodies (PLBS) growth of Phalaenopsis violacea orchid

The potential of different concentrations of various banana cultivars extracts, papaya extract, tomato extract and coconut water (0, 10, 20, 30%) to the control (without carbon source and plant growth regulator free medium) for reliable proliferation of Phalenopsis violacea protocorm-like bodies (PLB) under in vitro condition. The results indicated that organic extracts were taken up from the media as shown by the increased in percentage of PLB proliferation rate. Maximum growth of PLB was obtained in half-strength Murashige and Skoog (MS) semi-solid medium supplemented with 10% of Mas (AA) banana pulp extract. However, it has been noticed that at a higher concentrations of organic extract tend to be inhibitory to the PLB proliferation which could be due to the osmotic stress. PLBs grown in half-strength MS supplemented with papaya extract had the lowest PLB proliferation rate among the different organic extracts. It can be concluded that, adding Mas (AA) banana pulp extract at concentration of 10% can be a potential replacement of sucrose in the media. Therefore, the short time length of in vitro culture and its high efficiency makes addition of suitable organic extracts well suited for mass propagation of Phalenopsis violacea orchid

A Study on the Use of Organic Additives on the Protocorm-like Bodies (PLBS) Growth of Phalaenopsis violacea Orchid

The potential of different concentrations of various banana cultivars extracts, papaya extract, tomato extract and coconut water (0, 10, 20, 30%) to the control (without carbon source and plant growth regulator free medium) for reliable proliferation of Phalenopsis violacea protocorm-like bodies (PLB) under in vitro condition. The results indicated that organic extracts were taken up from the media as shown by the increased in percentage of PLB proliferation rate. Maximum growth of PLB was obtained in half-strength Murashige and Skoog (MS) semi-solid medium supplemented with 10% of Mas (AA) banana pulp extract. However, it has been noticed that at a higher concentrations of organic extract tend to be inhibitory to the PLB proliferation which could be due to the osmotic stress. PLBs grown in half-strength MS supplemented with papaya extract had the lowest PLB proliferation rate among the different organic extracts. It can be concluded that, adding Mas (AA) banana pulp extract at concentration of 10% can be a potential replacement of sucrose in the media. Therefore, the short time length of in vitro culture and its high efficiency makes addition of suitable organic extracts well suited for mass propagation of Phalenopsis violacea orchid

Histology and scanning electron microscopy observations of cryopreserved protocorm-like bodies of Dendrobium sonia-28

The genus Dendrobium possesses horticultural importance. Dendrobium sonia-28 is an important ornamental orchid in the flower industry. Cryopreservation is a favoured long-term storage method for orchids with propagation problems. Protocorm-like bodies (PLBs) of Dendrobium sonia-28 were cryopreserved using the vitrification technique. Histology and scanning electron microscopy (SEM) observations were conducted on stock, non-cryopreserved (control), and cryopreserved PLBs of Dendrobium sonia-28 to detect cryoinjuries resulting from the vitrification protocol. Histological observations of control PLBs indicated that the preculture, osmoprotection, and dehydration steps were not physically damaging to the PLBs. Histological and SEM analyses of cryopreserved PLBs indicated that the freezing and thawing cycles inflicted damages on the parenchymatic regions of the PLBs. Only embryogenic cells survived the treatment. Scanning electron microscopy studies of the control and cryopreserved PLBs indicated that both osmotic and freezing injuries occurred only in the interior regions of the PLBs

Damage potential of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) on cocoa beans: effect of initial adult population density and post infestation storage time

The effect of different initial adult population densities of Tribolium castaneum (Herbst) at several post infestation storage times on the final adult population density, the percentage of damaged beans, the percentage of weight loss, and the weight of insect feeding residues on cocoa beans was investigated in laboratory experiments. Both factors interactively had highly significant (P < 0.01) effects on variables assessed. The highest mean final adult population density of 129.7 ± 4.6 was recorded in samples infested with the highest initial adult population density and stored for 150 d, while the least mean adult population density of 10.8 ± 0.54 was recorded on samples infested with the lowest initial adult population density in samples stored for 30 d. The highest percentage damaged cocoa beans 51.0 ± 1.21% was recorded in samples infested with the highest initial adult population density, while the least mean percentage damaged beans of 16.9 ± 1.26% was also recorded on samples infested with the lowest initial adult population density. Similar trends of means were recorded for all the remaining variables. Correlation between factors was significant and positive. Multiple and simple linear regressions analyses were also significant (P < 0.01) and all equations fitted the regression models and perfectly described the relationship between the independent and the dependent variables. Our results show that T. castaneum can impact negatively on both the quantity and quality of stored cocoa within just 30 days of infestation, with the impact increasing with increasing population density and post infestation storage time