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Summary: The globally changing climatic condition is increasing the incidences of drought in several parts of the world. This is predicted and already shown to not only impact plant growth and flower development, but also plant–pollinator interactions and the pollination success of entomophilous plants. However, there is a large gap in our understanding of how drought affects the different flowers and pollen transfer among flowers in sexually polymorphic species.Here, we evaluated in monoecious Styrian oil pumpkin, and separately for female and male flowers, the responses of drought stress on flower production, petal size, nectar, floral scent and visitation by bumblebee pollinators.Drought stress adversely affected all floral traits studied, except floral scent. Although both flower sexes were adversely affected by drought stress, the effects were more severe on female flowers, with most of the female flowers even aborted before opening. The drought had negative effects on floral visitation by the pollinators, which generally preferred female flowers.Overall, our study highlights that the two flower sexes of a monoecious plant species are differently affected by drought stress and calls for further investigations to better understand the cues used by the pollinators to discriminate against male flowers and against flowers of drought‐stressed plants. See also the Commentary on this article by Buchmann & Papaj, 244: 746–748. [ABSTRACT FROM AUTHOR]

Plants inhabiting environments with stressful conditions often exhibit a low number of flowers, which can be attributed to the energetic cost associated with reproduction. One of the most stressful environments for plants is the Antarctic continent, characterized by limited soil water availability and low temperatures. Induction of dehydrins like those from the COR gene family and auxin transcriptional response repressor genes (IAAs), which are involved in floral repression, has been described in response to water stress. Here, we investigated the relationship between the water deficit‐induced stress response and the number of flowers in Colobanthus quitensis plants collected from populations along a latitudinal gradient. The expression levels of COR47 and IAA12 genes in response to water deficit were found to be associated with the number of flowers. The relationship was observed both in the field and growth chambers. Watering the plants in the growth chambers alleviated the stress and stimualted flowering, thereby eliminating the trade‐off observed in the field. Our study provides a mechanistic understanding of the ecological constraints on plant reproduction along a water availability gradient. However, further experiments are needed to elucidate the primary role of water availability in regulating resource allocation to reproduction in plants inhibiting extreme environments. [ABSTRACT FROM AUTHOR]

The use of treated domestic effluent in agriculture is important not only as a source of water but also as a source of nutrients for crops. In this context, the objective of this study was to evaluate its use for the production of ornamental sunflower cv. Anão de Jardim in a benchtype low-cost hydroponic system, inferring on its technical feasibility and observing the possible impacts on the crop. The experiment was carried out in a greenhouse, adopting a completely randomized design with four treatments (T1 - nutrient solution of Furlani 100%, prepared in municipal supply water - control), T2, T3 and T4 - nutrient solution of Furlani, respectively, with 100, 75 and 50% strength, prepared in treated domestic effluent and six replicates, totalizing 24 experimental units, each consisting of 15 plants. All treatments met the nutritional requirements of the plants and had adequate contents of N, P, K, Ca and Mg in leaf and stem at harvest, leading to satisfactory plant growth, and produced acceptable commercial grade capitula and stems. The plants under treatment T4, despite producing capitula of commercial quality, exhibited great variability in comparison to the other treatments, therefore except this treatment any other treatment can be used for hydroponic production of ornamental sunflower utilizing treated domestic effluents. [ABSTRACT FROM AUTHOR]

The experiment was conducted to evaluate the effect of growing media compositions containing cocopeat, FYM and vermiculite in different ratios on potted Chrysanthemum morifolium Ramat cultivar Kikiobiory (standard) for quality flower production. The results revealed that, vegetative growth with maximum plant height, number of leaves, root suckers per plant with delayed flowering were observed in media containing cocopeat + FYM (2:1)., whereas, the flower quality parameters like flower diameter and duration of flowering were highest in media containing vermiculite + FYM (2:1). However, plants showed the significant vegetative growth with better flowering time and quality in media composition cocopeat + vermiculite + FYM (1:1:1). Therefore, the findings suggest that for quality flower production of potted Chrysanthemum cv. Kikiobiory, light-weight growing media composition of cocopeat + vermiculite + FYM (1:1:1) was ideal with better plant morphological development and sustained flowering for display. [ABSTRACT FROM AUTHOR]

Terminal drought during the reproductive stage is a major constraint to yield of chickpea in many regions of the world. Termination of watering (WS) during podding in a small-seeded desi chickpea (Cicer arietinum L.) cultivar, Rupali, and a large-seeded kabuli chickpea cultivar, Almaz, induced a decrease in predawn leaf water potential (LWP), in the rate of photosynthesis, and in stomatal conductance. Compared to well-watered (WW) controls, the WS treatment reduced flower production by about two-thirds. In the WW treatment, about 15% of the flowers aborted and 42% (Rupali) and 67% (Almaz) of the pods aborted, whereas in the WS treatment 37% and 56% of the flowers aborted and 54% and 73% of the pods aborted, resulting in seed yields of 33% and 15% of the yields in WW plants in Rupali and Almaz, respectively. In vitro pollen viability and germination in Rupali decreased by 50% and 89% in the WS treatment, and pollen germination decreased by 80% in vivo when pollen from a WS plant was placed on a stigma of a WW plant. While about 37% of the germinated pollen tubes from WW plants and 22% from the WS plants reached the ovary in the WW plants, less than 3% of pollen grains reached the ovary when pollen from either WS or WW plants was placed on a stigma of a WS plant. It is concluded that, in addition to pod abortion, flower abortion is an important factor limiting yield in chickpea exposed to terminal drought and that water deficit impaired the function of the pistil/style more than the pollen. [ABSTRACT FROM PUBLISHER]

Abstract: The effect of foliar application of cytokinin (benzyl-adenine, 150mgL−1) and gibberellin (GA4 +GA7, 150mgL−1) on growth and flower development of 5-year-old plants of two jojoba clones was studied. The plant growth regulators were applied on October 5, 1999 (spring) and the plants were evaluated 120, 240 and 360 days after application. Shoot length, total number of nodes and number of nodes with branching were statistically different between clones but not between the growth regulator treatments. The total number of flowers on both clones was significantly increased by treatment with benzyl-adenine (BA) and significantly reduced by treatment with gibberellin. The seed yields, evaluated 180 days after application, were not statistically different from the control due to an increase in flower abortion. One clone treated with gibberellin showed a significant decrease in number and weight of seeds, the other did not. Histology of axillary buds revealed that BA application on one clone (4.11.32) enlarged the flower meristem, differentiating multiple flower production. [Copyright &y& Elsevier]

The size of apical growing points on four grades of sandersonia tuber (3–5, 5–7, 7–10 and >10 g) increased with increasing tuber weight (R2=0.71). These tubers were divided in two separate experiments to provide weights of 16.7, 33 and 50% and 50, 75 and 100% of the original grade size weights. Tubers were grown in the main season under standard forcing conditions. Harvested stem length was significantly greater with increasing tuber size, but declined with increasing severity of cutting treatment. Similar results also occurred with stem weight, flower number and vase-life. Regression analysis of stem length versus planted tuber size for the combined data from both experiments produced a significant relationship (R2=0.83), with the fitted line being: L=673.5−336.9×0.7626T (where L is the stem length, T the tuber planted weight and 673.5 is the upper asymptote). Stem size and flower number were influenced by tuber weight rather than by apical growing point size. [Copyright &y& Elsevier]