Effect of accel on the vase life and post harvest quality of alstroemeria (alstroemeria aurantiaca l.) cut flowers

Freshly cut flowering stems of Alstroemeria ‘Yellow King’ and ‘Marina’ were placed in glass jars containing solutions of Accel at 0, 25, 50, 75 and 100 mg/litre BA equivalent and arranged in a completely randomised design with 3 replicates. The effect of Accel on the vase life and qualityof Alstroemeria was investigated. Flowers held in Accel at 25 or 50 mg/litre BA equivalent consistently increased the number of days to full opening of primary florets and delayed the onset of flower senescence as measured by days to 50 % petal fall and days to 50 % leaf yellowing. Accel at 25mg/litre BA equivalent significantly increased the leaf nitrogen and chlorophyll content of Alstroemeria cut flowers. High Accel concentrations of 50, 75 and 100 mg/litre BA equivalent reduced significantly the leaf water content of Alstroemeria cut flowers. Accel at 75 and 100 mg/litre BA equivalentincreased leaf dry weight of Alstroemeria cut flowers. Our results indicate that Accel at 25 mg/litre BA equivalent has the potential to be used as a commercial cut flower preservative solution for delaying flower senescence, prolonging the vase life and enhancing post harvest quality of Alstroemeria cut flower

Identification of superior reference genes for data normalisation of expression studies via quantitative PCR in hybrid roses (Rosa hybrida)

<p>Abstract</p> <p>Background</p> <p>Gene expression studies are a prerequisite for understanding the biological function of genes. Because of its high sensitivity and easy use, quantitative PCR (qPCR) has become the gold standard for gene expression quantification. To normalise qPCR measurements between samples, the most prominent technique is the use of stably expressed endogenous control genes, the so called reference genes. However, recent studies show there is no universal reference gene for all biological questions. Roses are important ornamental plants for which there has been no evaluation of useful reference genes for gene expression studies.</p> <p>Results</p> <p>We used three different algorithms (BestKeeper, geNorm and NormFinder) to validate the expression stability of nine candidate reference genes in different rose tissues from three different genotypes of <it>Rosa hybrida </it>and in leaves treated with various stress factors. The candidate genes comprised the classical "housekeeping genes" (<it>Actin, EF-1α, GAPDH</it>, <it>Tubulin </it>and <it>Ubiquitin</it>), and genes showing stable expression in studies in <it>Arabidopsis </it>(<it>PP2A, SAND, TIP </it>and <it>UBC</it>). The programs identified no single gene that showed stable expression under all of the conditions tested, and the individual rankings of the genes differed between the algorithms. Nevertheless the new candidate genes, specifically, <it>PP2A </it>and <it>UBC</it>, were ranked higher as compared to the other traditional reference genes. In general, <it>Tubulin </it>showed the most variable expression and should be avoided as a reference gene.</p> <p>Conclusions</p> <p>Reference genes evaluated as suitable in experiments with <it>Arabidopsis thaliana </it>were stably expressed in roses under various experimental conditions. In most cases, these genes outperformed conventional reference genes, such as <it>EF1-α </it>and <it>Tubulin</it>. We identified <it>PP2A</it>, <it>SAND </it>and <it>UBC </it>as suitable reference genes, which in different combinations may be used for normalisation in expression analyses via qPCR for different rose tissues and stress treatments. However, the vast genetic variation found within the genus <it>Rosa</it>, including differences in ploidy levels, might also influence expression stability of reference genes, so that future research should also consider different genotypes and ploidy levels.</p

Effect of Benzyladenine on the Vase Life and Keeping Quality of Alstoemeria Cut Flowers

Two experiments were conducted to investigate the response of Benzyladenine (BA) on the vase life and the physiological changes in the leaves of Alstroemeria cut flowers. The treatments were combined in a factorial manner and laid down in a completely randomised design with 3 replicates. Treatment of Alstroemeria cut flowers with 25 or 50 mg/litre BA consistently increased the number of days to full opening of primary florets and delayed the onset of flower senescence as measured by days to 50 % petal fall and 50 % leaf yellowing. BA at 25, 50 or 75 mg/litre increased both the leaf nitrogen and chlorophyll content of the Alstroemeria cut flowers compared to the control. However, 75 and 100 mg/litre BA gave the highest values of leaf dry weight. BA decreased the leaf water content of Alstroemeria cut flowers. These results suggests that 25 mg/litre BA has the potential to be used as a commercial cut flower preservative to prevent leaf yellowing and prolonging the vase life of Alstroemeria cut flowers. KEY WORDS: Alstroemeria, benzyladenine, post harvest quality, vase life J. agric. Sci. technol. Vol.5(1) 2003: 91-10

Influence of Plant Growth Regulators on Postharvest Characteristics of Alstroemeria Cut Flowers

Cut Alstroemeria flowers cultivars “Yellow King” and “Marina” were obtained from a commercial farm and transported the same day to the laboratories of Crop Science Department, University of Nairobi in Kabete, Kenya. They were kept in holding solutions of various plant growth regulators and arranged in a completely randomised design. The objective of this study was to investigate the response to exogenous Accel (GA4+7:BA of 1:10), Provide (GA4+7), Silver thiosulphate (STS) and Florissant 200 on the vase life, leaf yellowing and the physiological changes in the leaves of Alstroemeria cut flowers. Applying Accel at 25 ppm BA equivalent, Provide at 10.0 ppm and Florissant 200 delayed rapid senescence as measured by days to onset of 50% petal fall, 50% leaf yellowing and retardation of leaf chlorophyll degradation. However, it was only Accel that delayed both the onset of 50% leaf yellowing by 41.4% days and opening of primary florets by 1.3 days, though it was not different from Provide and Florissant 200. STS (2 mM) increased days to 50% petal fall by 1.5 days but it decreased both water and leaf chlorophyll contents leading to insignificant accelerated onset of 50% leaf yellowing after 2 days. Florissant 200, STS, Provide and Accel retarded the rate of nitrogen degradation comparably as evidenced by high retention of nitrogen in the leaves compared to the control. Accel and Provide had pronounced effects in retarding leaf chlorophyll degradation and enhanced water content retention in Alstroemeria leaves, respectively. Our findings indicate that BA and /or GA4+7 applied together in the form of Accel had profound effect and great potential for delaying leaf senescence and prolonging the vase life of Alstroemeria cut flowers. Key Words: Alstroemeria-Benzyladenine (BA)-Gibberellins (GA4+7)-leaf yellowing-postharvest quality-Silver thiosulphate (STS) Résumé Les cultivars “Yellow King” et “Marina” de la fleur Alstroemeria ont été obtenus à partir d\'une ferme marchande et transportés le même jour aux laboratoires du Département d\'Agronomie de l\'Université de Nairobi sis à Kabete, Kenya. Ils ont été maintenus sur des supports en solution de divers régulateurs de croissance des plantes. Le test était arrangé dans un essai complètement aléatoire. L\'objectif de ces tests était d\'étudier l\'effet des régulateurs de croissance dont Accel exogène (GA4+7: BA, dans des rapports 1:10), Prorvide (GA4+7), Thiosulfate d\'Argent (TSA) et Florissant 200, sur la vie du calice, le jaunissement et les changements physiologiques de la feuille d\'alstroemère. Les applications de l\'Accel à raison de 25 ppm équivalents de Benzyhladenine (BA), de Prorvide à raison de 10,00 ppm et de Florissant 200, ont retardé la sénescence comme prouvé par le nombre de jours pris pour enregistrer la chute de 50 % des pétales, 50 % de jaunissement de la feuille et l\'altération retardée du chlorophylle dans la feuille. Bien que l\'Accel n\'ait pas montré des différences significatives par rapport à Provide et Florissant 200, il a toutefois retardé de 41,4% jours le jaunissement de 50% des feuilles, et de 1,3 jours l\'éclosion des fleurons primaires. Le thiosulfate d\'argent (2 mM) a prolongé de 1,5 jours la chute de 50% des pétales mais il a diminué la teneur hydrique et chlorophyllienne dans la feuille, déclenchant ainsi une accélération insignifiante de 2 jours, le jaunissement de 50% des feuilles. Florissant 200, Thiosulfate d\'argent, Provide et Accel ont retardé le taux de dégradation de l\'azote comme le prouve la teneur élevée en azote dans les feuille comparativement au témoin. Accel et Provide ont eu des effets marqués dans le retard de la dégradation de la chlorophylle dans la feuille et ils ont accru la potentialité de rétention hydrique de la fleur de l\'alstroemère. Nos résultats démontrent que les applications combinées de Benzyladenine et /ou des Gibbérellines sous forme d\'Accel ont un effet significatif et une grande potentialité de retarder la sénescence des feuilles et prolonger la vie du calice de l\'alstroemère. Mots clés: Alstroemeria, benzyladenine (BA), gibbérellines (GA4+7), jaunissement foliaire, quailté post-récolte thiosulfate d\'argent (TSA) Discovery and Innovation Vol. 16 (3&4) 2004: 195-20