Interaction of temperature and vegetative flush maturity influences shoot structure and development of lychee (Litchi chinensis Sonn.)

Potted lychee trees (cv. Tai so) of varying vegetative flush maturity were grown under a range of temperature regimes and monitored for subsequent shoot structure and development. A combination of low temperature (15/17 or 18/13 degreesC day/night) and high vegetative flush maturity was necessary for floral initiation to occur, Exposure to high temperatures (28/23 degreesC) invariably resulted in the production of vegetative shoots, irrespective of flush maturity. Strong floral initiation was marked by the emergence of terminal particles and accompanying axillary particles. A decrea,;e in vegetative flush maturity or increase in temperature (e.g. 23/18 degreesC) resulted in a decrease in axillary shoot formation and the production of several intermediate shoot structures. These included leafy particles, stunted particles, partially emerged buds and non-emergent swollen buds, often produced on the same tree. At 23/18 degreesC, closer synchronisation of initial flush maturity was required for the production of a consistent shoot-type. Trees with synchronised mature flushes (I-2) at 23/18 degreesC resulted in the production of swollen terminal buds. Healthy trees were maintained in this state for at least 11 months. These results indicate that both temperature and flush maturity can influence subsequent shoot structure of lychee. In the absence of either a strong floral temperature (18/13 degreesC) or strong vegetative temperature (28/23 degreesC), slight differences in initial flush maturity have gteater impact on the type of emerging shoot formed. (C) 2002 Elsevier Science B.V. All rights reserved.

Tipo de porta-enxerto e anelamento de ramos no pegamento da enxertia em lichieira (Litchi chinensis Sonn.)

O presente trabalho foi realizado em condições de ripado, com o objetivo de avaliar o desempenho da enxertia a inglês simples, em dois tipos de porta-enxerto (pé-franco e alporquia), em combinação com três tipos de anelamento do ramo (sem anelamento, e ramos anelados duas e quatro semanas antes da retirada do garfo), em lichia. O experimento foi conduzido em delineamento inteiramente casualizado, com seis tratamentos e três repetições. Foi somente observada diferença significativa para o tipo pé-franco, que revelou os melhores resultados.

Conservação das sementes de lichia (Litchi chinensis)

Avaliou-se o comportamento das sementes de lichia após o armazenamento. Utilizou-se de nove tratamentos (0; 1; 3; 5; 7; 9; 11; 13 e 15 dias de armazenamento em câmara de germinação, à temperatura de 10ºC e UR= 80-85%). A semeadura foi realizada em bandejas de poliestireno com substrato composto por Plantmax Hortaliças® + Osmocote® 14-14-14 (5g/L de substrato). A taxa de emergência (E%) e o índice de velocidade de emergência (IVG) das plântulas da testemunha (0 dia de armazenamento) não diferiram significativamente daqueles obtidos nos demais tratamentos. O período de armazenamento das sementes não afetou a taxa de emergência nem o IVE das plântulas de lichia até o limite estudado (15 dias).

Desenvolvimento do fruto da lichieira (Litchi chinensis Sonn.) 'Bengal'

Estudou-se o desenvolvimento do fruto da lichieira (Litchi chinensis Sonn.) 'Bengal'. Realizaram-se amostragens semanais, com início aos 35 dias após a antese e término no início da senescência dos frutos. A partir do 77º dia após a antese, os frutos foram decompostos em pericarpo, semente e arilo. A antese ocorreu na primeira semana de setembro. Foram ajustados modelos sigmoidais simples para acúmulo de matéria seca, comprimento e diâmetro. Para o acúmulo de matéria seca, uma fase inicial, de crescimento lento, prolongou-se até o 63º dia após a antese e coincidiu com um período de intensa queda natural de frutos. Do 63º ao 98º dia após a antese, houve uma fase de rápido acúmulo de matéria seca. Até o 77º dia, pericarpo e semente foram os principais responsáveis pelo acúmulo de matéria seca. Oitenta e oito por cento do comprimento e 65% do diâmetro máximos foram atingidos nesse período. Do 84º ao 98º dia após a antese, o desenvolvimento do fruto foi determinado basicamente pelo arilo. As dimensões e a matéria seca do fruto estabilizaram-se a partir do 98º dia após a antese. O ponto de colheita comercial dos frutos, caracterizado pela coloração avermelhada do pericarpo, ocorreu a partir do 112º dia após a antese. Verificou-se um quadro senescente nos frutos a partir do 119º dia após a antese.

Tipo de porta-enxerto e anelamento de ramos no pegamento da enxertia em lichieira (Litchi chinensis Sonn.)

O presente trabalho foi realizado em condições de ripado, com o objetivo de avaliar o desempenho da enxertia a inglês simples, em dois tipos de porta-enxerto (pé-franco e alporquia), em combinação com três tipos de anelamento do ramo (sem anelamento, e ramos anelados duas e quatro semanas antes da retirada do garfo), em lichia. O experimento foi conduzido em delineamento inteiramente casualizado, com seis tratamentos e três repetições. Foi somente observada diferença significativa para o tipo pé-franco, que revelou os melhores resultados.

Efeitos da aplicação de reguladores vegetais e do ácido bórico, em estacas de lichieira (Litchi chinensis Sonn.)

Estudaram-se as interações entre os ácidos indol-butírico, alfa-naftaleno-acético e bórico no desenvolvimento de calos e na sobrevivência das estacas de lichieira (Litchi chinensis Sonn.). As estacas apresentavam 25 cm de comprimento e 4 folhas cortadas pela metade, sendo retiradas em duas épocas diferentes (janeiro e abril) e colocadas para enraizar em bandejas de isopor, tendo como substrato vermiculita e em condições de câmara de nebulização. Foi feita imersão de 2,5 cm da base das estacas, em soluções aquosas por l minuto. Os tratamentos utilizados corresponderam a 5.000 e 2.000 ppm de IBA; 3.000 e 1.500 ppra de NAA; 150 microgramas/ml de H3BO3; IBA 5.000 e 2.000 ppm + H3BO(3)150 microgramas/ml; NAA 3.000 e 1.500 ppm + H3BO3 150 microgramas/ml e H2O. Avaliou-se a formação de calos e a sobrevivência das estacas após 120 dias do plantio. Através dos resultados obtidos, foi possível concluir que dos tratamentos utilizados, nenhum foi efetivo na formação de raízes, havendo somente a formação de calos. A melhor época para a retirada de estacas correspondeu ao mês de abril.

Enraizamento de estacas de lichia (Litchi chinensis Sonn.)

Estudou-se os efeitos de auxilias exógenas e ácido bórico, no enraizamento de estacas de lichia (Litchi chinensis Sonn.). As estacas foram uniformizadas, com 25 cm de comprimento e 4 folhas cortadas pela metade. Cerca de 2,5 cm da base das mesmas foi mergulhado nos tratamentos: H2O; Boro 150 µg/ml; IBA 5.000 ppm, IBA 2.000 ppm; IBA 5.000 ppm + Boro 150 µg/ml; IBA 2.000 ppm + Boro 150 µg/ml; NAA 3.000 ppm; NAA 1.500 ppm; NAA 3.000 ppm + Boro 150 µg/ml; NAA 1.500 ppm + Boro 150 µ/g/ml. A estaquia foi realizada no mês de setembro (Hemisfério sul), sendo que as estacas foram colocadas em bandejas de isopor, tendo como substrato vermiculita e mantidas sob nebulização intermitente. Os resultados obtidos permitiram concluir que o IBA 5.000 ppm por 1 minuto foi o tratamento mais efetivo, proporcionando 83,33% de estacas enraizadas em 120 dias, enquanto o tratamento testemunha (H2O), apresentou somente 16,67% de estacas enraizadas.

Evaluating of the activity antioxidant and fatty acids profile of lychee seeds (Litchi chinensis SONN.)

Purpose: The purpose of this paper is to characterize lychee seeds regarding their centesimal composition, and also to evaluate their antioxidant potential and fatty acid profile. Design/methodology/approach: To obtain the extract, dehydrated and grinded seeds were extracted with ethyl alcohol for 30 min, at a proportion of 1:3 of seeds:ethyl alcohol, under continuous agitation, at room temperature. Afterwards, the mixture was filtered and the supernatant subjected to a rotoevaporator at 40oC aiming to determine, by direct weighing, the extract dry matter yield. Findings: The largest found values went to the total carbohydrates (72.75 percent). In the oil from the lychee seeds there was a high percentage of unsaturated fatty acids, the main component being linoleic, considered an essential fatty acid. Research limitations/implications: Implies the identification of compounds biativos extracted from seeds of tropical and subtropical fruits, and to prevent certain types of diseases. Originality/value: The article tries to identify new source of phenolic compounds extracted from fruit. © Emerald Group Publishing Limited.

Lychee propagation (Litchi chinensis Sonn.): A comparative study of rootstocks

The lychee (Litchi chinensis Sonnerat), of the family Sapindaceae, is a highly valued fruit throughout the world. It is native to southern China, but it is cultivated in many parts of the world. In Brazil, the cultivation of the lychee was initiated in the 1970s in the State of São Paulo and has been increasing in production even though the crop size still averages only 1.4 ha per producer. The low crop size is attributed to the high cost of seedlings and the amount of time required for the plant to bear fruit. These factors discourage planting in large areas. The purpose of this research is to study some aspects of what is vitally important for the production of lychee seedlings on a large scale, with low cost and good genetic quality. Tests were performed using rootstocks from seeds of lychee and longan (Euphoria longan Lam.). Scions for grafting were taken from plants of lychee 'Bengal' in the collection of fruit species from FCAV-UNESP, Campus of Jaboticabal, Brazil. The experiments were started in September 2007 and the grafting process was performed in each month of the year finishing in August 2008. During this period the influence of these criteria were evaluated: 1) time of the year; 2) species of rootstock; 3) percentage of grafting success; 4) stem height at grafting point; 5) stem diameter at grafting point. Therefore, through statistical analysis we obtained significant differences in relation to the rootstock used, the months of the year in which the grafting was performed and the interaction between rootstock and the month in which the grafting was performed.

A Method to Estimate the Population Level of Aceria litchii (Prostigmata: Eriophyidae) and a Study of the Population Dynamics of This Species and Its Predators on Litchi Trees in Southern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Advances in understanding of enzymatic browning in harvested litchi fruit

Litchi (Litchi chinensis Sonn.) is a subtropical to tropical fruit of high commercial value in international trade. However, harvested litchi fruit rapidly lose their bright red skin colour. Peel browning of harvested litchi fruit has largely been attributed to rapid degradation of red anthocyanin pigments. This process is associated with enzymatic oxidation of phenolics by polyphenol oxidase (PPO) and/or peroxidase (POD). PRO and POD from litchi pericarp cannot directly oxidize anthocyanins. Moreover, PPO substrates in the pericarp are not well characterised. Consequently, the roles of PPO and POD in litchi browning require further investigation. Recently, an anthocyanase catalysing the hydrolysis of sugar moieties from anthocyanin to anthocyanidin has been identified in litchi peel for the first time. Thus, litchi enzymatic browning may involve an anthocyanase-anthocyanin-phenolic-PPO reaction. Current research focus is on characterising the properties of the anthocyanase involved in anthocyanin degradation. Associated emphasis is on maintenance of membrane functions in relation to loss of compartmentation between litchi peel oxidase enzymes and their substrates. (C) 2004 Elsevier Ltd. All rights reserved.

Impact of root and shoot temperature on bud dormancy and floral induction in lychee (Litchi chinensis Sonn.)

Potted lychee trees (cv. Tai so) with mature vegetative flushes were grown under three day/night temperature regimes known to induce floral (18/13degreesC), intermediate (23/18degreesC) and vegetative (28/23degreesC) shoot structures. Heating roots respective to shoots accelerated bud-break and shoot emergence, but reduced the level of floral initiation in emergent shoots. At 18/13degreesC, root temperatures of 20 and 25degreesC decreased the period of shoot dormancy from 9 weeks to 5 and 3 weeks, respectively. A root temperature of 20degreesC also increased the proportion of both leafy and stunted panicles to normal leafless panicles, and reduced the number of axillary panicles accompanying each terminal particle. A root temperature of 25degreesC produced only vegetative shoots. At 23/18degreesC, heating roots increased the proportion of vegetative shoots and partially emerged buds to leafy and stunted particles as well as accelerating bud-break. Cooling of roots in relation to the shoot resulted in non-emergence of buds at both 28/23 and 23/18degreesC. Bud-break did not occur until root cooling was terminated and root temperature returned to that of the shoot. At 23/18degreesC, subsequent emergent shoots had a greater proportion of leafy panicles relative to control trees. At 28/23degreesC, all emergent shoots remained vegetative. Lychee floral initiation is influenced by both root and shoot temperature. Root temperature has a direct effect on the length of the shoot dormancy period, with high temperatures reducing this period and the subsequent level of floral initiation. However, an extended period of dormancy in itself is not sufficient for floral initiation, with low shoot temperatures also a necessary prerequisite. (C) 2003 Elsevier B.V. All rights reserved.

Postharvest characteristics and handling of litchi fruit - an overview

Litchi ( Litchi chinensis Sonn.) is a tropical to subtropical crop that originated in South-East Asia. Litchi fruit are prized on the world market for their flavour, semi-translucent white aril and attractive red skin. Litchi is now grown commercially in many countries and production in Australia, China, Israel, South Africa and Thailand has expanded markedly in recent years. Increased production has made significant contributions to economic development in these countries, especially those in South-East Asia. Non-climacteric litchi fruit are harvested at their visual and organoleptic optimum. They are highly perishable and, consequently, have a short life that limits marketability and potential expansion of demand. Pericarp browning and pathological decay are common and important defects of harvested litchi fruit. Postharvest technologies have been developed to reduce these defects. These technologies involve cooling and heating the fruit, use of various packages and packaging materials and the application of fungicides and other chemicals. Through the use of fungicides and refrigeration, litchi fruit have a storage life of about 30 days. However, when they are removed from storage, their shelf life at ambient temperature is very short due to pericarp browning and fruit rotting. Low temperature acclimation or use of chitsoan as a coating can extend the shelf life. Sulfur dioxide fumigation effectively reduces pericarp browning, but approval from Europe, Australia and Japan for this chemical is likely to be withdrawn due to concerns over sulfur residues in fumigated fruit. Thus, sulfur-free postharvest treatments that maintain fruit skin colour are increasingly important. Alternatives to SO2 fumigation for control of pericarp browning and fruit rotting are pre-storage pathogen management, anoxia treatment, and dipping in 2% hydrogen chloride solution for 6-8 min following storage at 0 degrees C. Insect disinfestation has become increasingly important for the expansion of export markets because of quarantine issues associated with some fruit fly species. Thus, effective disinfestation protocols need to be developed. Heat treatment has shown promise as a quarantine technology, but it injures pericarp tissue and results in skin browning. However, heat treatment can be combined with an acid dip treatment that inhibits browning. Therefore, the primary aim of postharvest litchi research remains the achievement of highly coloured fruit which is free of pests and disease. Future research should focus on disease control before harvest, combined acid and heat treatments after harvest and careful temperature management during storage and transport.

Efeito da adubação nitrogenada na produção de mudas de lichieira

Devido à falta de informações sobre a aplicação de nitrogênio na produção de mudas de licheira na fase de viveiro, o experimento foi conduzido em viveiro no município de Urânia-SP (20°11' 25,4'' S e 50° 37' 42,9'' O). O delineamento experimental utilizado foi de blocos ao acaso, com cinco tratamentos, que consistiram em doses de nitrogênio aplicadas na forma de uréia (45% de N) (0, 800, 1.600, 2.400, 3.200 mg dm-³ de substrato) com quatro repetições e dez plantas por parcela. Após 104 dias do início do experimento, foi avaliado o comprimento da parte aérea e do sistema radicular, número de folhas e o teor de clorofila. Houve efeito significativo das doses de N apenas para comprimento da parte aérea e teor de clorofila. Na adubação nitrogenada de mudas de licheira, a dose de 2.188,33 mg dm-³ de N no substrato proporcionou o maior comprimento da parte aérea das plantas. O teor de clorofila nas folhas das mudas de lichia aumentou linearmente com o aumento das doses de nitrogênio.

Influence of the use of acids and films in post-harvest lychee conservation

Lychee (Litchi chinensis Sonn.) has a high commercial value; however, it has a short shelf-life because of its rapid pericarp browning. The objective of this study was to evaluate the shelf-life of 'Bengal' lychee fruits stored after treatment with hydrochloric acid and citric acid, associated with cassava starch and plastic packaging. Uniformly red pericarp fruits were submitted to treatments: 1-(immersion in citric acid 100 mM for 5 minutes + cassava starch 30 g L-1 for 5 minutes), 2-(immersion in hydrochloric acid 1 M for 2 minutes + starch cassava 30 g L-1 for 5 minutes), 3-(immersion in citric acid 100 mM for 5 minutes + polyvinyl chloride film (PVC, 14 µm thick)) and 4-(immersion in hydrochloric acid 1 M for 2 minutes + PVC film). During 20 days, the fruits were evaluated for mass loss, pericarp color, pH, soluble solids and titratable acidity, vitamin C of the pulp and pericarp and activities of polyphenol oxidase and peroxidase of the pericarp. The treatment with hydrochloric acid associated with PVC was the most effective in maintaining the red color of the pericarp for a period of 20 days and best preservation of the fruit. The cassava starch associated with citric acid, and hydrochloric acid did not reduce the mass loss and did not prevent the browning of lychee fruit pericarp.