Reproductive Development of White Clover (Trifolium repens L.) is Not Impaired by a Moderate Water Deficit That Reduces Vegetative Growth: I. Inflorescence, Floret, and Ovule Production

Abstract

Field experiments have shown that water deficit can either increase or decrease white clover (Trifolium repens L.) seed yield depending on its intensity. In order to explain this behavior, we evaluated the effect of water deficit intensity on the components of plant reproductive potential: number of reproductive stolons produced per plant (NSr), inflorescences per reproductive stolon (NI), viable florets per inflorescence (NFv) and ovules per floret (NO). Four experiments were conducted in greenhouse or growth chamber on white clover plants grown in large or small soil columns, or in small pots with vermiculite. Water supply was managed to maintain relatively constant values for predawn soil water potential and midday leaf relative water content (RWC) during the deficit period (20 to 68 d). Water deficit treatments were classified as moderate (M) or severe (S) on the basis of the reduction of RWC compared with the well‐watered plants (C) and of previously established relationships between RWC, soil water potential and vegetative growth. The development of inflorescences, florets and ovules were largely unaffected in M plants, while vegetative growth was depressed by reductions in leaf number per stolon (up to 30%), leaf area (30 to 40%), and by inhibition of stolon branching. Moderate water deficits induced an increase in the percentage of reproductive stolons per plant and reproductive phytomers per stolon. Although this positive effect on the reproductive to vegetative balance was generally observed with S water deficit, the reproductive potential of S plants was strongly depressed relative to C and M plants because of reduced stolon branching, phytomer production, and increased inflorescence and floret abortion. These results show that inflorescence, floret and ovule development of white clover were not impaired by a moderate water deficit that reduced vegetative growth, and suggest good prospects to manage optimal soil‐plant status to maximize potential of seed production.

Reproductive Development of White Clover (Trifolium repens L.) is Not Impaired by a Moderate Water Deficit That Reduces Vegetative Growth: II. Fertilization Efficiency and Seed Set

“…I n indeterminate legumes , maximal seed yield is generally obtained by plants subjected to a moderate water deficit, in comparison with well‐watered plants of white clover ( Trifolium repens L.; Danyach‐Deschamps and Wery, 1988; Oliva et al, 1994), alfalfa ( Medicago sativa L.; Steiner et al, 1992), pea ( Pisum sativum L.; Turc et al, 1990), or chickpea (Cicer arietinum L.; Wakrim‐Mezrioui and Wery, 1995). This yield improvement can be explained by a greater number of inflorescences for white clover (Danyach‐Deschamps and Wery, 1988; Oliva et al, 1994; Bissuel‐Belaygue et al, 2002), or a lower level of seed abortion for pea (Turc et al, 1992). A moderate water deficit in white clover plants was characterized by a reduction of soil water potential (to −80 × 10 −3 MPa) and avoidance of leaf wilting, but with significant reductions in stolon branching, leaf expansion and leaf production (Belaygue et al, 1996).…”

“…A moderate water deficit in white clover plants was characterized by a reduction of soil water potential (to −80 × 10 −3 MPa) and avoidance of leaf wilting, but with significant reductions in stolon branching, leaf expansion and leaf production (Belaygue et al, 1996). On the other hand, it increases the proportion of reproductive to vegetative organs and the number of inflorescences compared with well watered plants (Bissuel‐Belaygue et al, 2002). The development of inflorescences, florets, and ovules were largely unaffected by moderate water deficit (Bissuel‐Belaygue et al, 2002).…”

“…On the other hand, it increases the proportion of reproductive to vegetative organs and the number of inflorescences compared with well watered plants (Bissuel‐Belaygue et al, 2002). The development of inflorescences, florets, and ovules were largely unaffected by moderate water deficit (Bissuel‐Belaygue et al, 2002). These results show that a moderate soil dehydration produces a crop canopy with a high reproductive potential (high ratio of reproductive vs. vegetative organ numbers and thus a high number of ovules per unit area).…”

Is the pollination biology ofBathysaandSchizocalyxconsistent with their segregation? A first approach for two sympatric species in southeastern Brazil

“…Sexual reproductive performance has been referred to by varied terminology, such as effort, capacity, efficiency, and potential, and has been measured by different parameters (e.g., Hansen et al, ; Ramírez & Berry, ; Bissuel‐Belaygue et al, ; Quesada et al, ; Santos et al, ). In this study, we considered total ovule number per plant per flowering episode as the reproductive potential, and the proportion of ovules that were converted to seeds (i.e., fecundity) as the reproductive efficiency.…”

Floret initiation, tissue expansion and carbon availability at the meristem of the sunflower capitulum as affected by water or light deficits

“…However, mild water deficits during the vegetative period could promote floret initiation and grain production (Flénet et al. , 1996; Bissuel‐Belaygue et al. , 2002; Dosio, 2002).…”