• Energy Research

Fruit‐set involves a series of physiological and morphological changes that are well described for tomato and Arabidopsis, but largely unknown for sweet pepper (Capsicum annuum). The aim of this paper is to investigate whether mechanisms of fruit‐set observed in Arabidopsis and tomato are also applicable to C. annuum. To do this, we accurately timed the physiological and morphological changes in a post‐pollinated and un‐pollinated ovary. A vascular connection between ovule and replum was observed in fertilized ovaries that undergo fruit development, and this connection was absent in unfertilized ovaries that abort. This indicates that vascular connection between ovule and replum is an early indicator for successful fruit development after pollination and fertilization. Evaluation of histological changes in the carpel of a fertilized and unfertilized ovary indicated that increase in cell number and cell diameter both contribute to early fruit growth. Cell division contributes more during early fruit growth while cell expansion contributes more at later stages of fruit growth in C. annuum. The simultaneous occurrence of a peak in auxin concentration and a strong increase in cell diameter in the carpel of seeded fruits suggest that indole‐3‐acetic acid stimulates a major increase in cell diameter at later stages of fruit growth. The series of physiological and morphological events observed during fruit‐set in C. annuum are similar to what has been reported for tomato and Arabidopsis. This indicates that tomato and Arabidopsis are suitable model plants to understand details of fruit‐set mechanisms in C. annuum.

Fruit‐set involves a series of physiological and morphological changes that are well described for tomato and Arabidopsis, but largely unknown for sweet pepper (Capsicum annuum). The aim of this paper is to investigate whether mechanisms of fruit‐set observed in Arabidopsis and tomato are also applicable to C. annuum. To do this, we accurately timed the physiological and morphological changes in a post‐pollinated and un‐pollinated ovary. A vascular connection between ovule and replum was observed in fertilized ovaries that undergo fruit development, and this connection was absent in unfertilized ovaries that abort. This indicates that vascular connection between ovule and replum is an early indicator for successful fruit development after pollination and fertilization. Evaluation of histological changes in the carpel of a fertilized and unfertilized ovary indicated that increase in cell number and cell diameter both contribute to early fruit growth. Cell division contributes more during early fruit growth while cell expansion contributes more at later stages of fruit growth in C. annuum. The simultaneous occurrence of a peak in auxin concentration and a strong increase in cell diameter in the carpel of seeded fruits suggest that indole‐3‐acetic acid stimulates a major increase in cell diameter at later stages of fruit growth. The series of physiological and morphological events observed during fruit‐set in C. annuum are similar to what has been reported for tomato and Arabidopsis. This indicates that tomato and Arabidopsis are suitable model plants to understand details of fruit‐set mechanisms in C. annuum.

AbstractMaize is the highest yielding cereal crop grown worldwide for grain or silage. Here, we show that modulating the expression of the maizePLASTOCHRON1(ZmPLA1) gene, encoding a cytochrome P450 (CYP78A1), results in increased organ growth, seedling vigour, stover biomass and seed yield. The engineered trait is robust as it improves yield in an inbred as well as in a panel of hybrids, at several locations and over multiple seasons in the field. Transcriptome studies, hormone measurements and the expression of the auxin responsive DR5rev:mRFPer marker suggest that PLA1 may function through an increase in auxin. Detailed analysis of growth over time demonstrates that PLA1 stimulates the duration of leaf elongation by maintaining dividing cells in a proliferative, undifferentiated state for a longer period of time. The prolonged duration of growth also compensates for growth rate reduction caused by abiotic stresses.

AbstractMaize is the highest yielding cereal crop grown worldwide for grain or silage. Here, we show that modulating the expression of the maizePLASTOCHRON1(ZmPLA1) gene, encoding a cytochrome P450 (CYP78A1), results in increased organ growth, seedling vigour, stover biomass and seed yield. The engineered trait is robust as it improves yield in an inbred as well as in a panel of hybrids, at several locations and over multiple seasons in the field. Transcriptome studies, hormone measurements and the expression of the auxin responsive DR5rev:mRFPer marker suggest that PLA1 may function through an increase in auxin. Detailed analysis of growth over time demonstrates that PLA1 stimulates the duration of leaf elongation by maintaining dividing cells in a proliferative, undifferentiated state for a longer period of time. The prolonged duration of growth also compensates for growth rate reduction caused by abiotic stresses.

The aim of this study was to investigate the potential of bacterial strains of Bacillus, Pseudomonas, Escherichia, Micrococcus and Staphylococcus genera associated with wild herbaceous flora to enhance endogenous indole-3-acetic acid (IAA) content and growth of Triticum aestivum var. Inqalab-91.Gas chromatography and mass spectrometric (GC-MS) analysis revealed that bacterial strains produced 0.6-8.22 microg IAA ml(-1) in the presence of L-tryptophan. Plant microbe experiments showed a significant positive correlation between auxin production by bacterial strains and endogenous IAA content of T. aestivum for GC-MS (r = 0.618; P = 0.05) and colorimetric analysis (r = 0.693; P = 0.01). Similarly, highly significant positive correlation for shoot length (r = 0.627; P = 0.01) and shoot fresh weight (r = 0.626; P = 0.01) was observed with auxin production under axenic conditions. Bacterial inoculations also enhanced shoot length (up to 29.16%), number of tillers (up to 97.35%), spike length (up to 25.20%) and seed weight (up to 13.70%) at final harvest.Bacterial strains have the ability to increase the endogenous IAA content and growth of T. aestivum var. Inqalab-91.Microbial strains of wild herbaceous flora can be effectively used to enhance the growth and yield of agronomically important crops.

The aim of this study was to investigate the potential of bacterial strains of Bacillus, Pseudomonas, Escherichia, Micrococcus and Staphylococcus genera associated with wild herbaceous flora to enhance endogenous indole-3-acetic acid (IAA) content and growth of Triticum aestivum var. Inqalab-91.Gas chromatography and mass spectrometric (GC-MS) analysis revealed that bacterial strains produced 0.6-8.22 microg IAA ml(-1) in the presence of L-tryptophan. Plant microbe experiments showed a significant positive correlation between auxin production by bacterial strains and endogenous IAA content of T. aestivum for GC-MS (r = 0.618; P = 0.05) and colorimetric analysis (r = 0.693; P = 0.01). Similarly, highly significant positive correlation for shoot length (r = 0.627; P = 0.01) and shoot fresh weight (r = 0.626; P = 0.01) was observed with auxin production under axenic conditions. Bacterial inoculations also enhanced shoot length (up to 29.16%), number of tillers (up to 97.35%), spike length (up to 25.20%) and seed weight (up to 13.70%) at final harvest.Bacterial strains have the ability to increase the endogenous IAA content and growth of T. aestivum var. Inqalab-91.Microbial strains of wild herbaceous flora can be effectively used to enhance the growth and yield of agronomically important crops.

AbstractTrees are carbon dioxide sinks and major producers of terrestrial biomass with distinct seasonal growth patterns. Circadian clocks enable the coordination of physiological and biochemical temporal activities, optimally regulating multiple traits including growth. To dissect the clock's role in growth, we analysed Populus tremula × P. tremuloides trees with impaired clock function due to down‐regulation of central clock components. late elongated hypocotyl (lhy‐10) trees, in which expression of LHY1 and LHY2 is reduced by RNAi, have a short free‐running period and show disrupted temporal regulation of gene expression and reduced growth, producing 30–40% less biomass than wild‐type trees. Genes important in growth regulation were expressed with an earlier phase in lhy‐10, and CYCLIN D3 expression was misaligned and arrhythmic. Levels of cytokinins were lower in lhy‐10 trees, which also showed a change in the time of peak expression of genes associated with cell division and growth. However, auxin levels were not altered in lhy‐10 trees, and the size of the lignification zone in the stem showed a relative increase. The reduced growth rate and anatomical features of lhy‐10 trees were mainly caused by misregulation of cell division, which may have resulted from impaired clock function.