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The Bambusoideae subfamily includes the fastest-growing plants worldwide, as a consequence of fast internode elongation. However, few studies have evaluated the temporal and spatial distribution of endogenous hormones during internode elongation. In this paper, endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) were detected in different developmental internodes during shoot elongation by immunolocalization. Immunohistochemistry showed that IAA was mainly present in the shoot apex, leaf sheath primordia, parenchymal cells, and vascular tissues. During internode elongation and maturation, the IAA signals decreased significantly and then increased slightly, with the weakest signals observed in the rapidly elongating internode. Based on immunogold localization, most IAA signals were detected in the cytoplasm and nuclei of both parenchymal and fiber cells, and few signals were detected in cell walls in the unelongated and elongating internodes. After the completion of internode elongation, additional IAA signals were detected in the secondary walls of both parenchymal and fiber cells. Immunohistochemical localization of ABA showed that ABA signals decreased with internode elongation and maturation, with the weakest signal observed in the internodes of 3-month-old shoots. In addition, few ABA signals were detected in the shoot apex. The strongest IAA and ABA signals in unelongated internodes suggested that both hormones participated in the mediation of internode differentiation but not in the rapid elongation. Moreover, IAA was involved in secondary cell wall deposition. [ABSTRACT FROM AUTHOR]

The effects of bagging-induced light reductions on lycopene synthesis and the expression of related genes, antioxidant activity, and sugar composition of 'Tubtim Siam' pummelo (Citrus maxima) were investigated. Glucose, ascorbic acid, and flavonoid concentrations and 2, 2-diphenyl-1-picryhydrazyl scavenging activity were decreased in fruit covered with bags while still on the tree [0.01 μmol·m-2·s-1 photosynthetic photon flux density (PPFD)] compared with the untreated control (596.7 mmol·m-2·s-1 PPFD). The bagging treatment significantly decreased the temperatures on the surface in the bag. In addition, the bagging treatment decreased abscisic acid concentrations in the peel and pulp. However, the bagging treatment increased lycopene concentrations, upregulated phytoene synthase (CsPSY) and z-carotene desaturase (CsZDS) gene expressions; downregulated chromoplast-specific lycopene cyclase (CsbLCY), b-carotene hydroxylase (CsbCHX), and e-ring hydroxylase (CsECHX); and decreased 9-cis-epoxycarotenoid dioxygenase (CsNCED1) gene expressions in the pulp. It is possible that maintaining a temperature of '25 8C in fruit covered with bags may increase the lycopene concentration in the pulp with the upregulation of CsPSY and CsZDS and the downregulation of CsbLCY, CsbCHX, CsECHX, and CsNCED1 gene expressions in the pulp. [ABSTRACT FROM AUTHOR]

The article discusses the hermaphroditic reproduction of the Ceratopteris richardii ferns. Topics covered include the secretion of pheromones in the sex-determining process, the blocking of the female hormones by the hormone abscisic acid (ABA), and gene and gene network plasticity during evolutionary climate adaptation of plants. Also noted is ABA's role in ferns' response to low water availability.