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with 5 μM zeatin and routinely micropropagated through nodal sections to increase the number of clonal shoots available for rooting trials. Rooting of microshoots and acclimatization of plants to the greenhouse. Microshoots (2 to 3 cm in length) were

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mechanisms of rooting, such as different hormone balances between guarana cultivars ( Azevedo et al., 2015 ; Pacurar et al., 2014 ). Therefore, the endogenous concentration of rooting promoters or inhibitors may dispense or require the application of

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Oaks ( Quercus L.) are among the most important hardwood species in North America. Unfortunately, due to difficulty in vegetative propagation, hybrids and unique types of oaks are rarely introduced into the nursery trade. Poor rooting ability

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The relationship between auxin and adventitious root formation has been studied for many years. Indole-3-acetic acid plays a central role in adventitious rooting and was the first plant hormone used to stimulate the rooting of cuttings ( Cooper

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Abstract

A description for the design and use of a flowing solution culture for the mung bean bioassay is presented. A single module for the system is an assembly of polyvinyl chloride (PVC) pipe, Tygon tubing, and 12 hypodermic syringe barrels to accomodate 60 cuttings of mung bean, Vigna radiata (L.) R. Wilcz, (5 per syringe barrel). Solution is circulated by an electric fluid pump. A comparison of this system with conventional vial culture indicates no difference in mean root numbers and their standard deviation, although a more stable solution pH is maintained in the flowing system. In the vial system, pH drifted by as much as 1.4 units within 12 hours, but only 0.2 units in the flowing system. The system presented is ideal for investigations where a stable rooting environment is required.

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growth under water stress and aiding adventitious root formation ( Clark et al., 1999 ; Mergemann and Sauter, 2000 ; Sharp and LeNoble, 2002 ; Stepanova and Alonso, 2005 ). Research shows that ethylene injury may be prevented through chemical

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Trichoderma harzianum Rifai, a fungus that controls soilborne pathogens, can enhance growth of several vegetable and floriculture crops. Zero, 5, or 25 g of T. harzianum (isolate T-12) peat–bran amendment was added per kilogram medium in an effort to enhance the rooting of four chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] cultivars, two considered easy to root (`Davis' and `White Marble') and two considered hard to root (`Dark Bronze Charm' and `Golden Bounty'). Adding the T. harzianum amendment at both rates tested increased root and shoot fresh weights during 21 days of rooting, relative to the control. Supplementary treated cuttings were transplanted into nontreated growing medium after 21 days. Midway between transplant to flowering, increases in height, shoot dry weight, and root fresh and dry weight were detected in `Dark Bronze Charm' with T-12, relative to the control; increases in height, shoot fresh and dry weight, and number of nodes were detected in `Golden Bounty' with T-12. By this time, there were no detectable differences in `Davis' or `White Marble'.

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We investigated the role of ethylene on adventitious rooting of `Gala' (easy-to-root) and `Triple Red Delicious' (difficult-to-root) apple (Malus domestica Borkh.) microcuttings. Root count increased significantly as IBA level increased, with highest root counts on `Gala'. Ethylene evolution increased significantly with IBA level without significant differences between cultivars. Basal section removal of microcuttings in the area of root origin reduced root count without changing ethylene evolution. Ethylene treatment of proliferated shoots before microcutting excision failed to enhance rooting. IBA-induced ethylene evolution was eliminated nearly by AVG, but root count remained IBA dependent. ACC reversed IBA plus AVG rooting inhibition, but ACC alone failed to influence root count. Polar auxin transport inhibitors NPA and TIBA stimulated ethylene evolution without increasing root count. Adventitious rooting of apple microcuttings was not associated with ethylene. Chemical names used: 1-H-indole-3-butyric acid (IBA); aminoethoxyvinylglycine (AVG); 1-aminocyclopropane-1-carboxylic acid (ACC); 2,3,5-triiodobenzoic acid (TIBA); N-1-naphthylphthalamic acid (NPA).

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Abstract

In vitro propagated shoots of the apple rootstock, Antonovka 313 (Malus pumila Mill.)9 were rooted successfully in vitro. Roots became visible in 6-8 days, and 100% rooting after 2 weeks was achieved consistently in shoots cultured on modified Murashige and Skoog (MS) salt medium supplemented with 0.25 μm indole-3-butyric acid (IBA). Sucrose was the most influential medium component for rhizogenesis. Inorganic nutrients, IBA and vitamins did not influence rooting. Omitting activated charcoal caused only a slight decrease. A 1.5% sucrose solution added to a peat-vermiculite growing medium in vitro resulted in higher rooting than in treatments without sucrose.

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Adventitious root formation (rooting) in `Berken' mungbean [Vigna radiata (L.) Rwiclz.] cuttings is stimulated by indole-3-acetic acid (IAA). To understand the molecular events that occur during IAA-induced adventitious root initiation, a λgt11 cDNA library was made from mungbean hypocotyls treated with 500 μm IAA for 3 hours and differentially screened. Two cDNAs MII-3 and MII-4 were isolated. Southern analysis revealed that both cDNAs are encoded by different genes. Expression studies showed different patterns for both genes. Both MII-3 and MII-4 were highly expressed in IAA treated hypocotyls, whereas MII-4 was also induced in IAA treated epicotyls. There was no expression of either MII-3 or MII-4 in control or IAA treated leaves. With increasing concentrations of IAA from 100 to 1000 μm there was an increase in the average root number per cutting as well as a stimulation in MII-3 and MII-4. Both MII-3 and MII-4 showed a stimulation in expression 4 hours following treatment with 500 μm IAA reaching a maximum from 4 to 8 hours followed by a decline thereafter. Basal expression of MII-3 was evident between 2 and 8 hours, whereas, a high degree of basal expression was found with MII-4 from 1 to 8 hours followed by a sharp decline. Cycloheximide (50 μm) dramatically reduced rooting and MII-3 expression, whereas MII-4 was only slightly affected.

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