ABSTRACT
The aim of this study was to analyze photosynthate partitioning in tomato photomorphogenic mutants at the ends of the vegetative (40 days after emergence [DAE]) and reproductive (69 DAE) stages and to determine its interaction with morphoanatomical aspects. The mutants aurea (au), phytochrome-deficient, high pigment-1 (hp1), light-exaggerated response, were studied along with the non-mutant Micro-Tom (MT) cultivar. The plants were analyzed at 40 and 68 DAE to identify photosynthate source organs and tissues as well as the target organs of remobilized photosynthate during the reproductive stage. The plants were evaluated for their internal and external morphology as well as the percentage of dry mass of their organs. Photosynthate allocation in the hp1 mutant occurred primarily in the roots and leaves, and allocation in the au mutant occurred primarily in fruits. The au mutant showed a high capacity for photosynthate remobilization to fruit during the reproductive stage, and the predominant sources of these remobilized photosynthates were the leaf spongy parenchyma, the root vascular cylinder and the marrow stem.
O objetivo deste estudo foi analisar a partição de fotoassimilados em tomateiros mutantes fotomorfogenéticos ao final da fase vegetativa, aos 40 dias após a emergência (DAE), e ao final da fase reprodutiva, aos 69 DAE, e sua interação com aspectos morfoanatômicos. Foram estudados os mutantes aurea (au), deficiente em fitocromo, e hp1, o qual expressa resposta exagerada à luz, e o tomateiro selvagem cultivar Micro-Tom (MT). As plantas foram analisadas 40 dias após a emergência (DAE) e 68 DAE, tentando identificar os órgãos e tecidos dos fotoassimilados remobilizados e seus órgãos de destino durante o estádio reprodutivo. As plantas foram avaliadas quanto à sua morfologia interna e externa e percentagem de massa seca entre os órgãos. A alocação de fotoassimilados no mutante hp1 ocorreu prioritariamente em raízes e folhas comparativamente aos demais órgãos, e no mutante au ocorreu prioritariamente em frutos comparativamente aos demais órgãos. O mutante au deteve alta capacidade de remobilização de fotoassimilados durante sua fase reprodutiva para os frutos e os fotoassimilados remobilizados tiveram origem preponderante do parênquima lacunoso foliar, do cilindro vascular radicular e da medula caulinar.
Subject(s)
Phytochrome , Solanum lycopersicum , Crop Production , LightABSTRACT
In this article in order to build up an efficient regeneration system for cotyledons or hypocotyls of tomato MicroTom, two kinds of seed disinfectant (3% NaClO and 0.1% HgCl2 used for 5, 10, 15, 20 min), two types of basal medium (MS: Murashige and Skoog，1964, and B5: Gamborg et al.,1968), different ratio of Indole Butyric Acid (IBA: 0.05, 0.1, 0.2 mgL- 1) and 6-benzylaminopurine (6-BA: 1.0, 1.5, 2.0, 3.0 mgL-1) were tested. As for gene transform system, kanamycin (Kan: 0, 25, 50, 75, 100, 150mgL-1), carbenicillin, cephalosporin, cefoperazone sodium and sulbactam sodium for injection (Carb, CS, CSSS respectively) at the rate 100, 200, 300, or 500 mgL-1, respectively were added in medium B5 in order to find the suitable concentration for bacteriostasis and shoot regeneration. Moreover, cell concentration of Agrobacterium EHA105 (OD600: 0.3, 0.5, or 0.8）and infection time (5, 10, 15 min) were screened and optimized in this article. The results showed that 3% NaClO for 20 min is optimal as for the disinfect efficiency on the seed surface. The most suitable medium to induce adventitious bud is basal medium B5+0.05 mgL-1 IBA＋1.5 mgL-1 6-BA. The cotyledons and hypocotyls were cultivated in culture medium B5+IBA @ 0.05 mgL-1 for 2 d, then infected by Agrobacterium EHA105 (OD600=0.5) for 10 min, then plantlets were transferred to a fresh regeneration medium which contained 50 mgL-1 Kan and 300 mgL-1 CSSS, which was proved to be the most suitable transformation system for MicroTom.
ABSTRACT
Objetivou-se, neste trabalho, caracterizar aspectos fisiológicos de microtomateiros (Lycopersicon esculentum P. Miller cv. Micro-Tom) fitocromo-mutantes. A cultivar Micro-Tom e os mutantes aurea (deficiente na biossíntese do cromóforo dos fitocromos), atroviolacea (atv) e high pigment1 (hp1;ambos superexpressam eventos mediados por fitocromos) foram cultivados em condições controladas de luz e temperatura e caracterizados no estágio de floração. O mutante hp1 obteve as maiores taxas de fotossíntese potencial e de conteúdo de carotenóides. O mutante aurea manteve taxas de fotossíntese potencial similares à cultivar Micro-Tom, mesmo expressando o mais baixo conteúdo de clorofilas, e também expressou o maior conteúdo de nitrogênio entre os demais microtomateiros. Os mutantes aurea e hp1 obtiveram os menores conteúdos de açúcares solúveis totais. O mutante atv expressou o maior conteúdo de clorofilas e também a menor razão clorofila a/b.
The objective of this work was to characterize physiological aspects of micro-tomato (Lycopersicon esculentum P. Miller cv. Micro-Tom) phytochrome-mutants. Plants of Micro-Tom cultivar and aurea (deficient in phytochrome chromophore biosynthesis), high pigment1 (hp1) and atroviolacea (atv) (both super express phytochrome events-mediated) mutants were cultivated under controlled light and temperature and evaluated in flowering stage. The hp1 mutant expressed the highest rates of potential photosynthesis and also the content of total carotenoids. Aurea mutant maintained similar potential photosynthesis rates as the Micro-Tom cultivar, even containing low chlorophyll content, and expressed the highest content of nitrogen among all micro-tomatoes studied. Total soluble sugars were lower in aurea and hp1 mutants. The atv mutant expressed the highest content of chlorophylls and also the lowest rate of chlorophyll a/b.