Reproductive phenology in three Genisteae (Fabaceae) shrub species of the W Mediterranean Region
ABSTRACT We studied the flower duration, the phenology of flowering and fruiting, and flower, fruit, and seed production in three Genisteae shrub species of the W Mediterranean Region: Cytisus multiflorus, C. striatus, and Retama sphaerocarpa. Flower duration was negatively correlated with temperature, and in the case of C. striatus it was also influenced by pollination. In Cytisus multiflorus, which flowers during winter in the population studied, two floral morphs were recognized differentiated by flower size, phenological pattern, and production of the reproductive organs: morph LF (large flowers) and morph SF (small flowers). The former is earlier in phenology but its reproductive success is less than the second since it not only produces significantly fewer flowers/plant, but also a smaller crop of fruit and seeds. The flowering of the LF morph lasted some three months and of the SF morph 11 weeks. The winter-spring flowering C. striatus, with a four month duration of flowering time, is sympatric with C. multiflorus and their flowering periods overlap, but the former is more successful reproductively. Retama sphaerocarpa is clearly spring flowering, with an extremely short duration of flowering (c. 6.5 weeks), but, unlike the other two species which disperse their seeds in the same season in which they are produced, it staggers the dispersal of its diaspores over more than one year. Despite the great flower per plant production, especially in Retama sphaerocarpa, and of the number of fruit initiated, the final crop of fruit and seed/plant is low in the three species (C. multiflorus: fruit 8.40% and seeds 1.96%; C. striatus: fruit 13.09% and seeds 4.12%; Retama sphaerocarpa: fruit 5.65% and seeds 1.33%).
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ABSTRACT: We studied the reproductive biology of two leguminous shrubs endemic of the western Meditenanean region Cytisus striatus (Hill) Rothm. and Retama sphaerocarpa (L.) Boiss. The former is polliniferous, and the l atter is nectariferous, with maximum nectar production at the earliest hours of the morning. Germination of the pollen grains in the flowers of the two species occurs only after rupture of the stigmatic surface. It is also necessary in both cases that pollinators (mainly Apis mellifera) visir the flowers for fruit and seed set to occur. Our study of the pollen-pistil interaction indicated that there exists prezygotic self-incompatibility in these two species, probably of the gametophytic type, but some self-pollen tubes escape this control and self-fertilize some ovules. However, after hand sel f-pollination, fruit and seed set is very low for both species. This suggests the existence of a postzygotic rejection mechanism, which could be due either to the existence of late-acting self -incompatibility or to an early action of inbreeding depression, although there are lines of evidence that seem to point to the second possibility. Hand cross-polli nation led to an increased number of fruit and seeds per plant relative to the control plants, indicating that reproduction is pollen limited.Canadian Journal of Botany 10/1999; 77(6):809-820. · 1.40 Impact Factor
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ABSTRACT: In Cytisus multiflorus, a Genisteae endcmic shrub in the W Iberian Peníns ula, tvvo types of morphs were detected which are differcntiated b y the sizc of the flowers and the rc productive picces: the large-tlower (LF) morph and thc small-flower (SF) morph.Furthermorc, the pollen grains of thc LF morph are found to be l css Yiable than those of the SF morph. A st udy of the stigmatic receptivity in the two morph s indicates t hat the stigma is receptiYc both in opcn flowers and in tlower bud s cl ose to anth csis. The pollen grains are viable in both states; a res ult points to the ex istence of homogamy in this species. However, homogamy is not function al if the stigmatic surface has not been broken by pollinator visits. Hand, self-pollin ation experim cnts indicate that the pollen grains in both morphs germinate on th e stigma a nd t h eir pollen tubes penetratc the ovules; however, at a significantly lower perccntage th a n in hand, cross-pollination in t h e case of the LF morph, but not in the SF morph. Since there is a slight ove rlap in flowc ring period bchYeen t h e two morphs, cross pollinatio n may occur not only intramorph but also intermorph. Of the four possible combinations (LF x LF, LF x SF, SF x LF, and SF x SF), the SF x SF crosses are the most effective. This ma y be duc to the grcater viabilit y of the SF pollen gr a ins, indicating also a lower reproductiYe capacity of the LF morph with rcspect to the SF morph.8th International Pollination Symposium (ICPBR-ISHS); 07/2000
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ABSTRACT: The phenolic composition of the ethanolic extract obtained from the flowers of the medicinal plant Cytisus multiflorus has been elucidated by high performance liquid chromatography, electrospray mass spectrometry and nuclear magnetic resonance analysis. The extract was mainly composed of flavones, including the common chrysin, orientin, luteolin-5-O-glucoside, luteolin-7-O-glucoside, apigenin and apigenin-7-O-glucoside, which appeared as minor components. The major flavone in the extract was chrysin-7-O-β-d-glucopyranoside, and it also contained moderate amounts of a dihydroxyflavone isomer of chrysin, as well as of 2″-O-pentosyl-6-C-hexosyl-luteolin, 2″-O-pentosyl-8-C-hexosyl-luteolin and 6″-O-(3-hydroxy-3-methylglutaroyl)-2″-O-pentosyl-C-hexosyl-apigenin, which are not commonly found in the Fabaceae family. Other novel phenolic compounds found in the ethanolic extract of C. multiflorus comprised the flavones 2″-O-pentosyl-6-C-hexosyl-apigenin, 2″-O-pentosyl-8-C-hexosyl-apigenin and 6″-O-(3-hydroxy-3-methylglutaroyl)-2″-O-pentosyl-C-hexosyl-luteolin. The assessment of the biological activities of the main compounds of this extract are now keen, in order to determine their relevance in the beneficial properties of the plant.Food Chemistry 03/2012; 131(2):652–659. · 3.26 Impact Factor