Свежие комментарии

    Июнь 2025
    Пн Вт Ср Чт Пт Сб Вс
    « Июн    
     1
    2345678
    9101112131415
    16171819202122
    23242526272829
    30  

    Рубрики

    Посещаемость

    Сторонняя реклама

    Это тест.This is an annoucement of
    Тест.

    Статьи

    The relationship anywhere between outcrossing length and you can cumulative fitness wasn’t tall (quadratic regression: F

    13.05.2023 rencontres-nudiste visitors  No comments

    For two forest kinds from inside the Sri Lanka’s wet zone forests, fruits place increased significantly that have outcrossing point, peaking during the intermediate-point within this-forest crosses (1–10 kilometer based on types). When you look at the crosses between trees consuming separate forest supplies, not, fruit set are somewhat less (or nearly therefore) for both species. Alternatively, vegetables germination and you will seedling top within step one yr getting Sh. cordifolia recommended crossbreed vigor between-forest crosses. The results out of nearest-neighbors mating ranged among trees and you may varieties; new imply physical fitness cost of nearest-next-door neighbor mating relative to mating having sparingly significantly more faraway residents is 45% to own S. rubicundum and you can 0% to possess Sh. cordifolia. In contrast, the latest physical fitness negative effects of ranging from-tree crossing was indeed substantial for species (52 and you can 70% in line with inside-tree crosses for the very same a couple varieties). Crossing consequences diminished amongst the levels of fruit place and you will step 1-yr-dated seedling size; just the former try significant both for species. Results mean an effective potential for biparental inbreeding despair within forest forest communities and you will limited reproductive separation certainly one of woods occupying the remaining tree reserves into the Sri Lanka’s damp zone.

    Inbreeding depression can often be cited while the an inescapable outcome of anthropogenic disturbance so you can tropical forest (elizabeth.g., forest fragmentation, logging), in which idea forecasts you to definitely regular mating models contained in this already lowest-occurrence tree communities are managed to move on so you can prefer small-point crosses. Up to now, although not, the consequences off raised near-next-door neighbor mating getting populace exercise during the warm woods has actually yet in order to end up being quantified empirically. Two practical inquiries is handled are: Would grownups avoid maturing vegetables based on near-neighbors crosses and, if not, just how complement was near-neighbor-derived progeny according to anyone else? This study assesses the results of near-next-door neighbor mating in 2 warm forest species individually due to fitness contrasting from crosses ranging from nearby natives which have crosses involving far more faraway mates.

    Shorea cordifolia (Dipterocarpaceae) try a locally abundant chief shelter varieties that herbs greatly on unpredictable supra-annual periods (We. A great. U. Letter. Gunatilleke et al., unpublished analysis). Flowers associated with species was white and you can small-existed, and the winged fruits try distributed of the breeze otherwise the law of gravity. Because of its very minimal seed dispersal, hereditary relatedness one of close neighbors within the sheer forest is expected to getting high. In signed forest in the Sinharaja, Sh. cordifolia usually happens in clumps from ?5–20 adults, intermixed that have reduced stems (private observance).

    Study research

    For both species, within-treatment variation among maternal trees in fruit set was substantial for all outcrosses involving pollen donors within Sinharaja Reserve. In contrast, variation in fruit set rate was very low for between-forest crosses (Fig. 2). For Sh. cordifolia, fruit set for the distant between-forest treatment ranged from only 0.5 to 0.6% and was significantly lower than the mean fruit set rate for all within-forest outcrossing treatments combined (mean = 2.71%, Fstep 1,58 = 9.94, P < 0.0003). For S. rubicundum, mean fruit set for the distant between-forest treatment (2.67%) was low relative to mean fruit set rate for all within-forest outcrossing treatments combined (mean = 5.97%). The difference was nearly significant (Fstep one,58 = 3.78, P site de rencontres d’amis nudistes < 0.06).

    For Sh. cordifolia, cumulative fitness was maximum at both the distant neighbor and distant within-forest treatments (Fig. 5). Peak cumulative fitness observed for these intermediate crossing treatments was 2 and 4.3 times the cumulative fitnesses of the nearest-neighbor and distant between-forest treatments, respectively, although these differences were not significant (Table 3B). 2,8 = 3.70, P = 0.073). Mean cumulative fitness of open-pollinated flowers exceeded that of all other hand-pollination treatments, again likely due to the detrimental effect of the hand-pollination procedure on fruit set in this species. As for fruit set, mean cumulative fitness (relative) of the distant between-forest treatment (mean = 0.12) was significantly lower than that of all within-forest outcrossed classes combined (mean = 0.51, Fstep 1,twelve = 8.77, P = 0.012).

    Near-next-door neighbor crossing impact

    Near-neighbor crossing effects have been demonstrated for a number of coniferous species (Coles and Fowler, 1976; Park and Fowler, 1982, 1984; Latta et al., 1998), but only three studies have yielded evidence of near-neighbor crossing effects in woody angiosperms (Syzygium cormiflorum-Crome and Irvine, 1986; Schiedea spp.-Sakai, Karoly, and Weller, 1989; Eucalyptus globules-Hardner, Potts, and Gore, 1998). In another study suggestive of biparental inbreeding depression, mean fruit set rates were significantly lower for intraspecific crosses <0.5 km distance than for crosses >1 km distance for three subcanopy tree species (Inga spp.) in Costa Rica (Koptur, 1984). In fact, it may be that biparental inbreeding depression is common in natural populations of forest trees, but that estimation of its potential through experimental cross-pollinations has been limited to only a few species due to the obvious difficulty of working in the canopy. To my knowledge, there are no published reports of failed attempts to find near-neighbor crossing effects in natural populations of forest trees.

    Related Posts

    Related Posts:

    Leave a reply

    You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>