Rhizome

Rhizome tagging is not recommended for determining the plastochrone interval, but in the di-meristematic forms that have an apical rhizome meristem, tagging the rhizome is the only available method for determining P R and P S in these species (Hint 6). Rhizome marking is accomplished by wrapping a piece of wire or other tagging device around the rhizome, or the stem in some species, to determine the rhizome plastochrone interval (P R) ( Figure 8-4).

In all seagrass forms, the plant is tagged as closely behind the rhizome (or stem) meristem as possible ( Figure 8-4). To successfully tag the rhizome, sediments must be carefully excavated to expose the rhizome and to locate the rhizome meristem. This may be difficult in seagrass species with deep rhizomes, but there is no practical alternative. The tag is carefully secured around the rhizome, tightly enough to stay in place, but not too tightly to damage the tissue. After tagging, the rhizomes are re-buried to avoid physiological response to exposure.

Rhizome, horizontal underground plant stem that is capable of producing the shoot and root systems of a new plant. Rhizomes store starches and proteins and enable plants to survive underground during unfavorable seasons. Many plants use these structures for asexual reproduction.

Seagrass rhizome fragments for three growth forms showing how tagging is used to mark the rhizome (a) at the start of the growth study and (b) showing the new growth that has appeared after one plastochrone interval (P R=1). The meristem area(s) of growth (M 1, and M 2 if applicable) is indicated on each form.After an identified time interval (2-6 weeks, depending on the season and species), which must exceed the rhizome plastochrone interval (P R, Table 8-1), the tagged rhizome is excavated, including the new rhizome (beyond the tag) and at least three rhizome segments (each segment equals an internode plus one node) behind the tag. The rhizome segments and the new shoots produced since tagging are counted. To determine the rhizome and shoot plastochrone intervals:.nodes produced (nodes.

growing tip −1 day −1) is the count of new rhizome segments found on the rhizome between the node ahead of the tag and the youngest node.rhizome plastochrone interval, P R (days) is the time interval between production of new rhizome segments, measured as the number of days since marking divided by the number of rhizome segments produced.shoot production (shoots day −1) is the number of new shoots produced since rhizome tagging. Prabhakaran Nair, in, 2013 Storage of Seed RhizomeRhizomes, when required as seed, should be stored by heaping in well-ventilated enclosures and covered with turmeric leaves. Seed rhizome can also be stored in pits filled with sawdust (obtained from timber mills), sand, leaves of Glycosmis pentaphylla and Strychnos nux-vomica. The pits must be covered with wooden planks, with one or two holes made on their top for proper aeration and incidence of sunlight so that no rotting of the rhizomes takes place inside the pits. The rhizomes should be dipped in 0.075% of Quinalphos (a patented Indian fungicide) when scale infestations are observed and dipped in 0.3% Mancozeb (also a patented Indian fungicide) to contain storage losses due to fungal infestation. Venkatesha et al. (1997) found that rhizomes stored at 10°C, unlike in the case of all other treatments, did not rot, nor was there any sprouting.

However, these rhizomes showed low sprouting (33.05%) in the field. The most effective method for storage was to keep the rhizomes in 100-gauge polyethylene bags with 3% ventilation which ensures almost 100% (98.88% precisely) recovery of healthy rhizomes, which when subsequently planted in the field showed up to 91.9% sprouting. The above treatment showed. Prabhakaran Nair, in, 2013 Rhizome Scale ( Aspidiella hartii Ckll.)The rhizome scale ( A.

Hartii) (Diaspididae) infests rhizomes of ginger and turmeric both in the field and in storage in India. In the field, the pest infestation is generally seen during the dry post monsoon season and severely infested plants wither and dry.

In storage, the pest infestation results in shriveling of buds and rhizomes; when the infestation is severe, it adversely affects the sprouting rhizome ( Devasahayam and Koya, 2005). The adult females are minute in size, circular, and light brown to gray in color, measuring about 1.5 mm in diameter. Females are ovoviviparous and also reproduce parthenogenetically. The rhizome scale also infects yams, tannia, and taro ( Devasahayam and Koya, 2005). Management of the PestTimely harvest and discarding severely infested rhizomes during storage reduces further spread of the pest infestation in storage. Dipping of seed rhizomes in quinalphos 0.075% solution after harvest and storage in dry leaves of Strychnos nux-vomica L.+ sawdust in a 1:1 ratio is effective in controlling rhizome scale infestation on ginger and turmeric ( IISR, 2004–2005). Prabhakaran Nair, in, 2013 Rhizome EnlargementRhizome enlargement in ginger is by the activity of three meristematic zones.

Very early in the development of the rhizome, a zone of meristematic cells is formed at the base of a young scale leaf primordium of the developing rhizome. These meristematic cells develop into the primary thickening meristem (PTM) and procambial stands. The meristematic activity of the PTM is responsible for the initial increase in the width of the cortex. The second type is the actively dividing ground parenchyma. The third type is the secondary thickening meristem (STM), in which fusiform and ray initials are clearly visible. The STM develops just below the endodermoidal layer.At a lower level, in the rhizome from the shoot bud apex, the PTM can still be identified.

The scattered vascular bundles develop from the PTM or procambial cells. Such groups of cells can be identified by the plane of cell division.

The differentiation of procambial cells into vascular tissue takes place at different stages of rhizome growth. Unlike in many monocots, in the ginger rhizome there is a special meristematic layer along with the endodermoidal layer, and this layer consists of cambium-like cells. The cells are thin-walled and arranged in a biseriate manner. In certain loci, where the vascular bundles develop, these cells are elongated with tapered ends and appear similar to the fusiform initials with an average of 62.34 µm length and 8.12 µm width in mature stages. Between these fusiform initials, some cells show transverse divisions to form ray initials. The presence of the cambium-like layer is an important feature in rhizome development.

From this layer, inverted and irregularly distributed groups of xylem and phloem are formed along the intermediate layer. The cells outer and inner to the cambial layer become filled with starch gains. Prabhakaran Nair, in, 2013 RhizomeThe rhizome is the underground stem of turmeric, which can be divided into two parts, the central pear-shaped “mother rhizome” and its lateral axillary branches known as “fingers.” Normally, there is only one main axis.

Either a complete finger or a mother rhizome is used as planting material. It is also called the “seed rhizome.” Normally, the “seed rhizome” produces only one main axis, which develops into the aerial leafy shoot. The base of the main axis enlarges and becomes the first formed unit of the rhizome which ultimately develops into the mother rhizome.

Axillary buds from the lower nodes of the “mother rhizome” develop and give rise to the first order of branches, often called the “primary fingers.” Their number varies from two to five. Primary branches grow to some length and either develop into an aerial shoot or stop growing further. They grow in a haphazard manner in different directions and in some cases grow up to the ground level with one or two, or even no, leaves. Secondary branches developing at higher nodes of primary branches are diageotropic ( Raju and Shah, 1975). Some primary branches after hitting ground level do not form any aerial shoot, but, exhibit positive geotropic growth. Such branches arising from the mother rhizome may be diageotropic, orthogeotropic, plagiotropic ( Ravindran et al., 2007). Primary fingers branch further, resulting in secondary and tertiary branches, and these branches do not produce aerial shoots.

The majority of them show positive geotropic growth or obliquely downward growth. Longa types have more sideward growth, while the C. Aromatica types have more downward growth ( Ravindran et al., 2007). 1.Seed rhizome selection: The seed rhizomes should be selected from disease-free areas, as the disease can spread through rhizomes which appear to be normal. 2.Rhizome treatment: Seed rhizomes can be treated with a carbendazim + Mancozeb combination or carbendazim (0.25%) before planting.

Prochloraz, Tebuconazole, Chlorothalonil, Mancozeb, Captan, and Chlorothalonil + Copper gave the best control and increased ginger yield in Brazil ( De Nazareno, 1995). 3.The natural way to control leaf spot is to grow ginger under shade trees, such as coconut trees. Prabhakaran Nair, in, 2013 Host PlantsRhizome scale also infests a few other rhizomatous plants, such as tuber crops. In India, the pest has been recorded on ginger ( Zingiber officinale Rosc.), elephant foot yam ( Amorphophallus paeoniifolius (Dennst.) Nicolson), yams ( Dioscorea alata L., Dioscorea esculenta (Lour.) Burkill, and Dioscorea rotundata Poir), tannia ( Xanthosoma sagittifolium (L.) Schott), and taro ( Colacasia esculenta (L.) Schott) ( Ayyar, 1940). In other countries, such as West Indies, Ivory Coast, Ghana, and Nigeria, rhizome scale has been found to infest yams and tannia.

It also infests sweet potato in Africa ( Ballou, 1916). Rhizome extract of Zingiber officinale, which acts as both a reducing and a stabilizing agent, was used for the synthesis of AuNPs with a particle size ranging from 5 to 15 nm by Kumar et al. The particles were highly stable at physiological condition compared to citrate capped NPs ( Kumar et al., 2011). Karuppaiya et al. (2013) reported that the aqueous extract of Dysosma pleiantha rhizome was able to biosynthesize spherical AuNPs with an average of 127 nm within 20 min. The biosynthesized AuNPs were nontoxic to cell proliferation and also they could inhibit the chemo-attractant cell migration of human fibrosarcoma cancer cell line HT-1080 by interfering with the actin polymerization pathway ( Karuppaiya et al., 2013).

Nagajyothi reported the synthesis of spherical and rod shaped ZnO NPs in the range of 2.90–25.20 nm using Coptidis Rhizoma. They demonstrated the role of primary and secondary amine, aromatic and aliphatic amine, alcohol, carboxylic acid, alkyl halide, alkynes in the formation of ZnO NPs ( Nagajyothi et al., 2014). The list of species that have been used to synthesize metals nanoparticles by Rhizome extract were shown in Table 4.

PlantMetalSize (nm)ShapeReferenceZingiber officinaleAu5–15SphericalKumar et al. (2011)Dioscorea oppositifoliaAg 100 (DLS)14 (TEM)SphericalMaheswari et al.

(2012)Dysosma pleianthaAu127SphericalKaruppaiya et al. (2013)Gloriosa superbaAg63–70–Alagar Yadav et al. (2013)CoptidisZnO2.90–25.20Spherical, rodNagajyothi et al. (2014)Acorus calamusAgAu31.8315 and 20 (XRD)100–500 (SEM)SphericalSphericalNakkala et al. (2014))Ganesan and Gurumallesh Prabu (2015)Alpinia galangalAg–SphericalAlyza and Norhidayah (2015)Zingiber officinaleAg and Fe 3O 45–25 (Ag)1–3 (Fe 3O 4)CrystallineIvashchenko et al. Prabhakaran Nair, in, 2011 2.6.1.4 Rhizome Rot DiseaseRhizome rot disease is also known as clump rot.

The onset of the disease occurs during the southwest monsoon. Park (1937) was the first to report the occurrence of the disease. Subba Rao (1938) described the disease as clump rot. Rhizome rot disease is widely distributed throughout cardamom plantations in the states of Kerala and Karnataka and also in Tamil Nadu, where heavy rainfall occurs, as in the Anamalai hills.

Symptoms of the DiseaseIt is during the southwest monsoon, by about the middle of June, that the disease makes its appearance. The first visible symptoms are a pale-yellow color in the foliage, and wilting and the premature death of older leaves. The collar portion of the aerial shoots becomes brittle, and the tiller breaks off with just slight physical disturbance. Rotting develops at the collar region, which becomes soft and brown. At this stage, the affected aerial shoots fall off, emitting a foul smell.

Mayne (1942) reported the incidence of the disease in cardamom hills of the state of Kerala. The tender shoots or the young tillers also turn brown and rot completely. With the advancement of the disease, all the affected aerial shoots fall off from the base. The panicles and young shoots attached to the base also are affected by the rot.

Rotting extends to the rhizomes and the roots. The falling off of shoots resulting from rhizome rot infection becomes severe during July–August. In severely affected areas, as much as a 20% incidence of disease is recorded.

Causal PathogenSubba Rao (1938) observed that cardamom rhizome rot is caused by Rhizoctonia solani Kuhn. And associated the pathogen with a nematode. Ramakrishnan (1949) reported Pythium vexans de Barry as the causal pathogen. Thomas and Vijayan (1994) reported that Fusarium oxysporum is also occasionally found to cause rhizome rot and root infections. Disease ManagementThe disease is usually observed in areas previously affected by rhizome rot disease. Therefore, phytosanitation plays an important role in disease management.

The presence of inoculum in the soil and in plant debris, overcrowding of plants, and thick shade all promote the development of the disease; therefore, any disease management schedule has to be followed with these factors in mind. The application of superphosphate at the rate of 300–400 g per plant has been recommended for controlling clump rot in cardamom plantations ( Anon., 1955). Soil drenching with 1% Bordeaux mixture or 0.25% copper oxychloride or neem oil cake at the rate of 500 g per plant, followed by one round of premonsoon and two rounds of postmonsoon soil drenching with 0.25% copper oxychloride at an interval of a month has been reported to be effective in controlling the disease ( Thomas and Vijayan, 1994). Biological ControlAs in the case of capsule rot, attempts to control rhizome rot disease make use of Trichoderma sp., namely, Trichoderma viride and Trichoderma harzianum ( Thomas et al., 1991b). A formulation of Trichoderma harzianum in a carrier medium consisting of farmyard manure and coffee husk mixture has been developed for field application in an integrated disease management system for the control of rot diseases of cardamom ( Thomas et al., 1997). Prabhakaran Nair, in, 2013 Disease ResistanceRhizome rot disease is endemic to Andhra Pradesh, India, where turmeric is extensively cultivated.

Nier automata pc mod. In these endemic situations, varieties such as PCT 8, PCT 10, PCT 13, PCT 14, Suguna, and Sudharshana were found tolerant to the disease ( Rao et al., 1992, 1994). The local high-yielding varieties like Armoor, Duggirala, and Mydukur were found to be highly susceptible, whereas in Assam State, India, the cultivars like Mydukur, Tekurpet, and Duggirala were found susceptible, while cultivars Ca 69 and Shillong were found to be resistant ( Rathaiah, 1982b).The variety CLI 370 was found moderately tolerant to rhizome rot ( Sankaraiah et al., 1991).

Screening germplasm for disease resistance under artificial inoculation showed that CA 17/1, CA 146/A, and Suvarna were free of disease incidence. In field conditions, rotting was higher among long-duration genotypes, followed by medium duration and then short-duration ones, sequentially ( Anandam et al., 1996). Turmeric variety TCP-2, a clonal selection from the State of West Bengal, India, and developed by Uttar Banga Krishi Viswavidyalaya (UBKVV) in Pundibari, Cooch Behar district, West Bengal, India, showed moderate resistance to rhizome rot ( Ravindran et al., 2002).Host range studies of the rhizome rot pathogen, P.

Aphanidermatum, conducted at IISR, Calicut, Kerala State, India, showed that among the five turmeric species, C. Aromatica, and C. Caesia were found resistant to pathogenic infection (Anon, 2007–2008).