The auxins, including indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and naphthaleneacetic acid (NAA), promotes the formation of adventitious root in hypocotyls of soybean (Glycine max). IBA significantly promotes the formation of adventitious roots more than IAA and NAA . The activity of anionic pI 3.7 peroxidase (POX) and cationic pI 8.5 POX were inhibited by exogenous auxins during the induction of adventitious root on day 2. Besides, the activity of pI 5.3 POX was enhanced by IBA during the initiation stage on day 4. The increase of the activity of pI 5.3 POX was accompanied by the increase of H2O2 levels. In the previous researches, it shows that the promoter of pI 8.5 POX gene contains both ARF/AuxRE and CATATGGMSAUR motifs that are responded to auxins. In this studies, the pI 5.3 POX gene, which responses to auxins a day or two later, contains only ARF/AuxRE motif. The regulation of pI 5.3 POX gene is probably initiation phase-dependent. The results suggest that anionic pI 5.3 POX produces significant amount of H2O2 through the binding of auxin to POX and mediate the auxin signaling pathway leading to plant growth .

Synthetic auxin, naphthaleneacetic acid ( NAA ), promoted rooting in soybean ( Glycine max ) hypocotyls. The activities of anionic peroxidases (PODs, pI 3.5 and pI 3.7 ) and cationic PODs ( pI 8.3, pI 9.1 and pI 9.4 ) in soybean hypocotyls were significantly inhibited by exogenous NAA during the induction of adventitious roots. In addition, the reduction in the activity of PODs ( pI 4.4, pI 8.3 and pI 9.4 ) were correlated with a reduction of their corresponding transcription activity. The PODs patterns and transcription in the NAA-treated hypocotyls demonstrated the specific effect of NAA on POD ioszymes, indicating that NAA might suppress PODs genes expression during the adventitious root formation. The decline of PODs activity in the NAA-treated hypocotyls was accompanied by the decrease of lignin contents. We suggest that both of anionic and cationic PODs might be in part responsible for lignin synthesis in soybean hypocotyls.

Synthetic auxin, indole-3-butyric acid (IBA), effectively promoted the rooting in Cinnamomum kanehirae cuttings. The easy-to-root genotype, H107, responded to IBA much earlier than the difficult-to-root genotype, L41. On day 5, the POD activity significantly decreased in the IBA-treated tissues as compared with the control. Similar phenomenon was observed in extract of L41 genotype showing that IBA inhibited POD activity. In addition, the variation in POD activity corresponds to an inverse variation in the concentration of free IAA. The levels of IAA in H107 genotype increased dramatically in IBA-treated tissues on day 5; while, in L41 genotype, the raise of IAA in IBA-treated tissues was observed on day 20. Moreover, the lignin content in IBA-treated H107 cuttings decreased is quite correlated with the decline of the POD activity; yet the lignin content in L41 genotype cuttings was almost unchanged. Hence, we suggest that the inhibition on POD may lead to the redifferentiation processes induced by IBA, then produce the new root primordia during the formation of adventitious roots.

Auxin can induce adventitious rooting. Synthetic auxin, indole-3-butyric acid (IBA), effectively promoted the rooting in Cinnamomum kanehirae. The peroxidase (POX) activity significantly decreased in the IBA-treated tissues as compared with the control. Hence, I suggest that the inhibition on POX activity may lead to the redifferentiation processes induced by IBA, which produces the new root primordia during the formation of adventitious roots. On this investigation, I cloned POX cDNA from the young roots. Degenerate primers were designed from the conservative regions of other published POX to amplify the expectant DNA fragment. Full-length cDNA of the POX gene designated CKPX1 and CKPX3 were cloned by the method of 5'and 3' RACE. The deduced amino acid of CKPX1 and CKPX3 were compared with the previously reported POX and showed between 40% and 60% identity with those plant species. Further studies on the promoter elements of CKPX3 were found out that elements related to auxin response, lignification, pathogen invasion and stress response. The results suggest that CKPX3 may be involved in the regulate process of adventitious rooting and defense against pathogens and environment stress.

Auxin can induce adventitious rooting. Synthetic auxin, indole-3-butyric acid (IBA), effectively promoted the rooting in Cinnamomum kanehirae. In Cinnamomum kanehirae, there are high (H) and low (L) rooting cultivar. The peroxidase (POX) activity significantly decreased in the IBA-treated tissues as compared with the control. The inhibition on POX activity may lead to the redifferentiation processes induced by IBA. In this investigation, we cloned POX cDNA from the young roots. Degenerate primers were designed from the conservative regions of other published POXs to amplify the expectant DNA fragment. We found that the H and L line have similar genes (>99%). The Full-length cDNA of the POX genes were cloned by the method of 5'and 3' Rapid Amplification of cDNA Ends (RACE). The deduced amino acid were compared with the previously reported POX and showed between 40% and 70% identity with other plant POXs. Further studies on the promoter elements of POX in High-rooting cultivar and Low-rooting line show that some elements are related to auxin response, lignification, pathogen invasion and stress response. The regulatory elements of the POX gene in High-rooting line contain sugar repression responsiveness (SRS) elements that might repress the expression of POX gene, causing the lower POX activity.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-06-07T11:55:12Z No. of bitstreams: 2 Dissertação - Yuri de Oliveira Castro - 2017.pdf: 2073976 bytes, checksum: 2173380278c4268f1f75502613d21754 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-06-07T11:55:32Z (GMT) No. of bitstreams: 2 Dissertação - Yuri de Oliveira Castro - 2017.pdf: 2073976 bytes, checksum: 2173380278c4268f1f75502613d21754 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-06-07T11:55:32Z (GMT). No. of bitstreams: 2 Dissertação - Yuri de Oliveira Castro - 2017.pdf: 2073976 bytes, checksum: 2173380278c4268f1f75502613d21754 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Encourage the adventitious roots can bring increments to the culture of tomatoes for industrial processing (TI). The objective of this study was to determine the effect of positions transplanting and ages of adventitious roots in changes in plant development in TI productivity. Three experiments were carried out arranged in factorial scheme (3 x 3 + 2): three positions of transplanting (collect level, at the level of the cotyledon and at the level of the first leaf fully expanded) in three ages of change (30, 60 and 90 days after sowing-DAS) and a free additional position (at the level of the last leaf fully expanded) for the ages of 60 and 90 DAS. The changes of the 30 did not present last leaf fully expanded and did not receive the last position of transplanting. In experiment 1 (one) the contribution of the zones or regions Annals (collect the cotyledon; the cotyledon to the first leaf; the first sheet to the last leaf fully expanded) to the number of roots adventitious issued. The Count took place every two days after transplanting (DAT) and was held until the 20º DAT. The experiment was designed entirely with four replicates and plots sub-plot. In experiment 2 (two) to evaluate the architecture of the root system of seedlings of thee through images of the roots of plants cultivated in rizontrons (phenotyping platform of high performance) and analyzed by software WinRHIZO PRO 2013. The experiment was designed in complete randomized blocks (DBC) with five repetitions. In experiment 3 (three) measured periodically the leaf area and dry mass of aerial part of plants, equations of partition and fotoassimilados allocation. The experiment was designed in DBC with six repetitions. The area between the collect and the cotyledon presented the highest number of adventitious roots in all ages of change, with quadratic responses to 60 and 90 of seedlings and seedlings for 30 DAS. The issue of roots beyond the 20º day may be related to better hormonal and nutritional condition of 30 seedlings of compared with the seedlings of 60 and 90 DAS. The depth of the root system is linked to a greater leaf area, although the contribution of photosynthesis for the adventitious roots become less relevant than other factors such as nutritional status of changes. The leaf area and dry mass of plant organs were influenced by age of change. Seedlings of 30 and 60 DAS the present greater leaf area, dry mass accumulation and distribution of roots when compared with 90 DAS the seedlings. Productivity did not differ between the ages of 30 and 60 DAS and was higher if compared to 90 DAS seedlings. / Incentivar o enraizamento adventício pode trazer incrementos à cultura do tomate para processamento industrial (TI). Objetivou-se neste estudo determinar o efeito de posições de transplantio e idades de muda no enraizamento adventício, no desenvolvimento vegetal e na produtividade de TI. Foram realizados três experimentos: experimento 1 (um): em estufa com mudas transplantadas em tubetes para produção de mudas florestais; experimento 2 (dois): em casa de vegetação com mudas transplantadas em rizotron; experimento 3 (três): em campo aberto. No experimento 1 (um) avaliou-se a contribuição das zonas ou regiões caulinares (do coleto ao cotilédone; do cotilédone à primeira folha; da primeira folha à última folha totalmente expandida) para o número de raízes adventícias emitidas. A contagem ocorreu a cada dois dias após o transplantio (DAT) e foram realizadas ate o 20º DAT. O experimento foi delineado inteiramente ao acaso com quatro repetições. No experimento 2 (dois) avaliou-se a arquitetura do sistema radicular de mudas de TI através de imagens das raízes de plantas cultivadas em rizontrons (plataforma de fenotipagem de alto desempenho) e analisadas pelo software WinRHIZO PRO 2013. O experimento foi delineado em blocos completos casualizados (DBC) com cinco repetições em esquema fatorial adicional 3 x 3 + 2, no qual, mudas de 30, 60 e 90 DAS foram transplantadas em 3 níveis (coleto, cotilédone e primeira folha) e as idades de 60 e 90 DAS receberam um nível adicional de transplantio cada (última folha). No experimento 3 (três) mediu-se periodicamente a área foliar e a massa seca da parte aérea das plantas, obtendo-se equações de partição e alocação de fotoassimilados. O experimento foi delineado em DBC com seis repetições em esquema fatorial adicional 3 x 3 + 2 (idem ao experimento 2). A zona entre o coleto e o cotilédone apresentou o maior número de raízes adventícias em todas as idades de muda, com respostas quadráticas para mudas de 60 e 90 DAS e linear para mudas de 30 DAS. A emissão de raízes além do 20º dia pode estar relacionada à melhor condição hormonal e nutricional das mudas de 30 DAS comparada com as mudas de 60 e 90 DAS. A profundidade do sistema radicular está ligada a uma maior área foliar, apesar de a contribuição da fotossíntese para o enraizamento adventício ser menos relevante que outros fatores como o estado nutricional da muda. A área foliar e a massa seca dos órgãos vegetais foram influenciadas pela idade da muda. Mudas de 30 e 60 DAS apresentam maior área foliar, acúmulo de massa seca e distribuição de raízes quando comparadas com mudas de 90 DAS. A produtividade não diferiu entre as idades de 30 e 60 DAS e foi maior se comparada às mudas de 90 DAS.

Morphological and anatomical studies demonstrated the root formation characteristics of sweet potato. The presence and importance of preformed root primordia is recorded for the first time. On the vines root primordia are present in sets of four to ten adjacent to the leaf bases. These roots originate from the procambium on both sides of the leaf gap. Macroscopically the root tips of preformed root primordia protruding through the cortex and epidermis of the stems are prominent. The preformed root primordia produce adventitious roots, with pentarch, hexarch or septarch steles. Storage roots will under normal circumstances only originate from undamaged root primordia on the nodes of cuttings, or on nodes of newly formed vines, or from wound roots originating from the cut ends of the stem or leaf cuttings. Lateral roots originating from damaged root primordia, or directly from the adventitious roots, exhibit tetrarch steles and develop into fibrous roots without the potential to develop into storage roots. This understanding of the origin, anatomy and morphology of sweet potato roots should improve production practices, which will contribute to improved crop establishment and increased yield. Differences in the contribution of individual subterranean nodes to storage root yield were studied. On average cuttings with three subterranean nodes produced 3.7 storage roots, with 33.2% on subterranean node 1, 30.0% on node 2 and 36.8% on node3. However, in terms of fresh mass of the storage roots node 1 contributed 45.4%, node 2 contributed 27.1% and node 3 contributed 27.4%. The effect of temperature (20, 24, 28 and 32oC constant), orientation of cuttings (vertical vs. horizontal) and size of cuttings (1 or 3 nodes) on the development of adventitious roots was observed in plant growth chambers. Twenty-one days after planting, the longest total root length of 4m per plant was recorded from the 24oC growth chamber. The effect of soil moisture content on early root development was investigated by wetting and equilibrating sandy soil to 100, 80, 60 and 40% of field capacity. Although the 80% of field capacity treatment resulted in the best root development, differences among treatments were small, demonstrating the capacity of cuttings to successfully establish under a range of soil moisture contents. Changes in dry mass of storage roots, stems, and leaves of three sweet potato cultivars (Awasa-83, Bareda and Falaha) were studied at Awasa and Melkassa. At the final sampling the early maturing cultivar Falaha had diverted a higher proportion of the total dry mass into storage roots at Melkassa because of the early initiation and growth of storage roots. The late maturing cultivar Awasa-83 had a smaller proportion of the total dry mass diverted into the storage roots at both locations because of late root initiation and growth. The high yielding cultivars Bareda at Melkassa, and Awasa-83 at Awasa, had higher crop growth rates and higher net assimilation rates than the other cultivars. The effects of cultivar (Kudadie, Bareda and Awasa-83), planting position (horizontal and vertical), type of planting material (terminal cuttings with and without leaves) and cutting length (20, 25 and 30 cm) on the number and yield of storage roots were quantified in field trials at Awasa and Melkassa. Cultivar Kudadie produced the highest storage root yield at both locations. Horizontal planting of cuttings resulted in the highest total storage root yield at both locations. Cutting length did not affect storage root number and yield. The effect of population density (50,000, 55,555, 75,000, and 100,000 cuttings per hectare) on the performance of the three Ethiopian sweet potato cultivars was studied at Awasa. The highest planting density consistently produced the best root yield, indicating the potential to increase yields with plant populations much higher than normally used. Early maturing cultivar Falaha produced more small and medium storage roots per plant, while the intermediate cultivar Bareda produced more large storage roots. Copyright 2003, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Belehu, T 2003, Agronomical and physiological factors affecting growth, development and yield of sweet potato in Ethiopia, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-07262004-141704 / > / Thesis (PhD (Plant Production and Soil Science))--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted