Many flowering plants are unable to set seeds with their own pollen because a system known as gametophytic self-incompatibility is operating. The basis of this system is a single multiallelic locus S, and if the S allele carried by a pollen grain matches one of the two S alleles carried in the style, as it is certain to do upon self-pollination, then pollen tube growth is inhibited. Should one ...

BACKGROUND Peltophorum pterocarpum and Delonix regia are dominant avenue trees in the city of Kolkata in India. They are well adapted to the humid tropical climate and also grow commonly in different parts of the country. Their pollen grains are reported to be airborne. OBJECTIVE The aim of this study was to conduct an aerobiological survey in Kolkata to determine the concentration and season...

We examined pollen grains and starch granules from a large number of modern populations of teosinte (wild Zea spp.), maize (Zea mays L.), and closely related grasses in the genus Tripsacum to assess their strengths and weaknesses in studying the origins and early dispersals of maize in its Mesoamerican cradle of origin. We report new diagnostic criteria and question the accuracy of others used ...

Global climate change, especially, increases in carbon dioxide (CO2) concentration and the associated increases in temperature will have significant impact on the crop production. Grain-sorghum [Sorghum bicolor (L.) Moench] cultivar DeKalb 28E was grown at daytime maximum/nighttime minimum temperature regimes of 32/22, 36/26, 40/30 and 44/34 8C at ambient (350 mmol CO2 mol ) and elevated (700 m...

Using a newly developed vibrating electrode, we have explored the electric fields around lily pollen germinating in vitro. From these field measurements, we infer that each weeted pollen drives a steady current of a few hundred picoamperes through itself. Considered as a flow of positive ions, this current enters an ungerminated grain's prospective growth site and leaves it opposite end. Aft...

In Japan, Cryptomeria japonica pollen are scattered during each spring season. Daughter allergenic particles are released, which are smaller in size than their parent pollen grain and are abundant in a particle size below 1.1 μm in the atmosphere; nevertheless, Cryptomeria japonica pollen size is about 30 μm. Therefore, daughter allergenic particles of pollen are transported in the urban atmosp...

OsSPX1, a rice SPX domain gene, involved in the phosphate (Pi)-sensing mechanism plays an essential role in the Pi-signalling network through interaction with OsPHR2. In this study, we focused on the potential function of OsSPX1 during rice reproductive phase. Based on investigation of OsSPX1 antisense and sense transgenic rice lines in the paddy fields, we discovered that the down-regulation o...

Within modern gymnosperms, conifers and Ginkgo are exclusively wind pollinated whereas many gnetaleans and cycads are insect pollinated. For cycads, thrips are specialized pollinators. We report such a specialized pollination mode from Early Cretaceous amber of Spain, wherein four female thrips representing a genus and two species in the family Melanthripidae were covered by abundant Cycadopite...

Tradescantia pollen grains, isolated during the period of DNA synthesis in the generative cell, accumulate deoxythymidine triphosphate (dTTP)-(3)H after incubation with thymidine-(3)H in the presence of millimolar deoxyadenosine. Most of this dTTP-(3)H was found to resist extraction by the fixative, cold ethanol-acetic acid, and its location was investigated by radioautography with thin, dry em...