We aim to evaluate the evolutionary trends of pollen ultra-structures and microstructures in the light of molecular phylogeny, and to test whether pollen micromorphology is a predictor of interspecific phylogenetic re...We aim to evaluate the evolutionary trends of pollen ultra-structures and microstructures in the light of molecular phylogeny, and to test whether pollen micromorphology is a predictor of interspecific phylogenetic relationship or a consequence of ecological influences. Using scanning electron microscopy pollinia micromorphologies of 18 species of the genus Dendrobium were comprehensively examined. A phylogenetic tree from ribosomal-ITS2 sequences was constructed reflecting molecular phylogeny. In result, two major clusters were identified representing the sections Aporum, Formoase Dendrobium and Holochrysa. The section Dendrobium could be further classified, for the first time, into two clades sharing the same root of origin. Variations in the shape of pollinia were distinct and consistent constituting six novel groups. Other qualitative/quantitative keys to pollinia showed congruence with molecular phylogeny and supported the correlated evolution of these traits. Concurrently pollen sculpturing also showed large variation in exine morphology (rugular/psilate to psilate-scabrate/rugulate-scabrate) providing explicit clues for phylogenetic trend of exine evolution. For the characteristic sculpturing on the pollinia surface, a simple version of pre-pattern model is also hypothesized for deeper insight into pattern formation in other biological systems. Results indicated that distinct groups of Dendrobium species have parallel and independent evolution accompanied with genetic changes occurred during species diversification. Thus pollen micromorphology is a good candidate for inferring the genetic relationship at inter-specific level having phylogenetic implications even using abundant palynological records.展开更多
Olive tree,Olea europaea L.,is considered the most important tree in Jordan.The olive pit scale,Pollinia pollini Costa(Hemiptera:Asterolecanidae)has become a destructive threat to some olive groves in Jordan.A field s...Olive tree,Olea europaea L.,is considered the most important tree in Jordan.The olive pit scale,Pollinia pollini Costa(Hemiptera:Asterolecanidae)has become a destructive threat to some olive groves in Jordan.A field study was conducted in an olive grove located in Northern Jordan during the growing season of 2015 to determine the population dynamics of this pest on two olive cultivars:Grossidi and Nebali Baladi,grown under rain-fed conditions.Terminal twigs were randomly sampled from the periphery of the canopy on each experimental tree at on month intervals throughout the entire year.Each sample was inspected thoroughly under a dissecting microscope in the laboratory for the presence of the immature and mature pit scale insect.The Grossidi olive cultivar was significantly more susceptible to P.pollini than Nebali Baladi,as indicated by the development of higher populations throughout the year.There was strong evidence that P.pollini overwintered as adults.Three generations were recorded per annum.The first generation occurred in February and March,followed by others from May to June and from August to November,respectively.The first two generations were significantly larger than the third one.Based on these observations,the greatest abundance of crawlers occurs in mid-March and mid-May,and therefore,application of insecticides is recommended during this period of time,since crawlers lack a waxy covering on their body and thus facilitates the chemical penetration through the cuticle,making them more susceptible to insecticides.Moreover,farmers are encouraged to cultivate the native Nebali Baladi cultivar rather than the more susceptible,introduced Grossidi cultivar in areas subject to heavy infestation.展开更多
Aims The hypothesis of predator satiation has been proposed to explain mast fruiting in various flowering plants.it considers that the simultaneous production of large numbers of seeds by a plant population reduces th...Aims The hypothesis of predator satiation has been proposed to explain mast fruiting in various flowering plants.it considers that the simultaneous production of large numbers of seeds by a plant population reduces the risk of seed predation for each individual.orchids produce huge numbers of seeds per fruit and rarely experience seed predation.it remains unclear which factors may affect fluctuating fruit production in orchids,which generally suffer a widespread pol-len limitation.To explore the temporal pattern of fruiting and poten-tial factors related to fluctuation in fruit production,we investigated reproductive success of a long-spurred orchid(Habenaria glaucifo-lia)in an alpine meadow with thousands of individuals over 8 years.Methods To estimate reproductive success,pollinator observation was con-ducted by day and at night,and pollinia removal and receipt were recorded in the field population for 8 years.To examine whether fruit set and seed set are pollen limited,we conducted supple-mentary pollination experiments and compared fruit set,seed set and pollinia movement of open-pollinated flowers from 2011 to 2013.We measured lengths of spurs and pollinator probos-cises,and nectar volume and concentration,to identify potential pollinators.Important Findings Hawkmoths were seen to be effective pollinators for H.glauci-folia in 3 years,whereas in the remaining 5 years no pollinators were observed,and consequently pollinia were rarely transferred.Numerous pollinia movements were observed in 2012,2013 and 2014(pollinia removal:48,59 and 85%;pollinia receipt 51,70 and 80%),and correspondingly fruit set was significantly higher in 2012 and 2013(59 and 46%)than in 2011(25%).it was fruit set,rather than seed set,that was pollen limited in this orchid in the 3 years,in that supplementary pollination increased fruit set but did not increase seed set per fruit compared to natural.Three species of hawkmoths had proboscis lengths that matched the spur length of H.glaucifolia.Fruit set in this long spurred orchid depends on the activity of long-tongued hawkmoths,resulting in significant tempo-ral variation in fruit production.mast fruiting in this alpine orchid could be attributed to a‘sit and wait’strategy,awaiting an abun-dance of effective pollinators.展开更多
文摘We aim to evaluate the evolutionary trends of pollen ultra-structures and microstructures in the light of molecular phylogeny, and to test whether pollen micromorphology is a predictor of interspecific phylogenetic relationship or a consequence of ecological influences. Using scanning electron microscopy pollinia micromorphologies of 18 species of the genus Dendrobium were comprehensively examined. A phylogenetic tree from ribosomal-ITS2 sequences was constructed reflecting molecular phylogeny. In result, two major clusters were identified representing the sections Aporum, Formoase Dendrobium and Holochrysa. The section Dendrobium could be further classified, for the first time, into two clades sharing the same root of origin. Variations in the shape of pollinia were distinct and consistent constituting six novel groups. Other qualitative/quantitative keys to pollinia showed congruence with molecular phylogeny and supported the correlated evolution of these traits. Concurrently pollen sculpturing also showed large variation in exine morphology (rugular/psilate to psilate-scabrate/rugulate-scabrate) providing explicit clues for phylogenetic trend of exine evolution. For the characteristic sculpturing on the pollinia surface, a simple version of pre-pattern model is also hypothesized for deeper insight into pattern formation in other biological systems. Results indicated that distinct groups of Dendrobium species have parallel and independent evolution accompanied with genetic changes occurred during species diversification. Thus pollen micromorphology is a good candidate for inferring the genetic relationship at inter-specific level having phylogenetic implications even using abundant palynological records.
文摘Olive tree,Olea europaea L.,is considered the most important tree in Jordan.The olive pit scale,Pollinia pollini Costa(Hemiptera:Asterolecanidae)has become a destructive threat to some olive groves in Jordan.A field study was conducted in an olive grove located in Northern Jordan during the growing season of 2015 to determine the population dynamics of this pest on two olive cultivars:Grossidi and Nebali Baladi,grown under rain-fed conditions.Terminal twigs were randomly sampled from the periphery of the canopy on each experimental tree at on month intervals throughout the entire year.Each sample was inspected thoroughly under a dissecting microscope in the laboratory for the presence of the immature and mature pit scale insect.The Grossidi olive cultivar was significantly more susceptible to P.pollini than Nebali Baladi,as indicated by the development of higher populations throughout the year.There was strong evidence that P.pollini overwintered as adults.Three generations were recorded per annum.The first generation occurred in February and March,followed by others from May to June and from August to November,respectively.The first two generations were significantly larger than the third one.Based on these observations,the greatest abundance of crawlers occurs in mid-March and mid-May,and therefore,application of insecticides is recommended during this period of time,since crawlers lack a waxy covering on their body and thus facilitates the chemical penetration through the cuticle,making them more susceptible to insecticides.Moreover,farmers are encouraged to cultivate the native Nebali Baladi cultivar rather than the more susceptible,introduced Grossidi cultivar in areas subject to heavy infestation.
基金National Science Foundation of China(U1402267 and 31270281)to S.-Q.H.
文摘Aims The hypothesis of predator satiation has been proposed to explain mast fruiting in various flowering plants.it considers that the simultaneous production of large numbers of seeds by a plant population reduces the risk of seed predation for each individual.orchids produce huge numbers of seeds per fruit and rarely experience seed predation.it remains unclear which factors may affect fluctuating fruit production in orchids,which generally suffer a widespread pol-len limitation.To explore the temporal pattern of fruiting and poten-tial factors related to fluctuation in fruit production,we investigated reproductive success of a long-spurred orchid(Habenaria glaucifo-lia)in an alpine meadow with thousands of individuals over 8 years.Methods To estimate reproductive success,pollinator observation was con-ducted by day and at night,and pollinia removal and receipt were recorded in the field population for 8 years.To examine whether fruit set and seed set are pollen limited,we conducted supple-mentary pollination experiments and compared fruit set,seed set and pollinia movement of open-pollinated flowers from 2011 to 2013.We measured lengths of spurs and pollinator probos-cises,and nectar volume and concentration,to identify potential pollinators.Important Findings Hawkmoths were seen to be effective pollinators for H.glauci-folia in 3 years,whereas in the remaining 5 years no pollinators were observed,and consequently pollinia were rarely transferred.Numerous pollinia movements were observed in 2012,2013 and 2014(pollinia removal:48,59 and 85%;pollinia receipt 51,70 and 80%),and correspondingly fruit set was significantly higher in 2012 and 2013(59 and 46%)than in 2011(25%).it was fruit set,rather than seed set,that was pollen limited in this orchid in the 3 years,in that supplementary pollination increased fruit set but did not increase seed set per fruit compared to natural.Three species of hawkmoths had proboscis lengths that matched the spur length of H.glaucifolia.Fruit set in this long spurred orchid depends on the activity of long-tongued hawkmoths,resulting in significant tempo-ral variation in fruit production.mast fruiting in this alpine orchid could be attributed to a‘sit and wait’strategy,awaiting an abun-dance of effective pollinators.
