Germinating nasturtium pollen (Tropaeolum majus) is shown to excrete an enzyme(s) which hydrolyzes all types of monomers from biosynthetically labeled cutin and p-nitrophenyl esters, which are model substrates for fungal cutinases. The pollen cutinase showed an optimum pH near 6.5 and was inhibited by thiol-directed reagents such as p-hydroxymercuribenzoate and N-ethyl maleimide but not by diis...

Intact sperm cells of Plumbago zeylanica were released from mature pollen grains near anthesis using osmotic shock with 20% sucrose. Sperm cell yields of up to 75% can be attained by differential centrifugation using a clinical centrifuge with concentrations of up to 8.8 x 10(6) cells/milliliter. Such ;gametoplasts' remain intact for up to 24 hours according to Evan's blue exclusion and can be ...

Most chrysanthemum cultivars are self-incompatible, so it is very difficult to create pure lines that are important in chrysanthemum breeding and theoretical studies. In our previous study, we obtained a self-compatible chrysanthemum cultivar and its self-pollinated seed set was 56.50%. It was interesting that the seed set of its ten progenies ranged from 0% to 37.23%. Examination of the factor...

In the solanaceous plant Nicotiana alata, self-incompatibility is controlled by a single, multiallelic locus (S locus) expressed in both pollen and pistil. Previously, we have shown cosegregation between alleles of the S locus and alleles of a gene that encodes a glycoprotein with ribonuclease activity (S-RNase). Furthermore, expression of the S-RNase gene is apparently confined to the pistil a...

The success of sexual reproduction in plants involves (i) the proper formation of the plant gametophytes (pollen and embryo sac) containing the gametes, (ii) the accomplishment of specific interactions between pollen grains and the stigma, which subsequently lead to (iii) the fusion of the gametes and eventually to (iv) the seed setting. Owing to the lack of mobility, plants have developed spec...

Reactive Oxygen Species (ROS) are compounds derived from oxygen with important implications in biological processes plants, some of them related to reproduction. Among ROS, superoxide is the primary oxidant, since an array other ROS eventually this anion. Therefore, analysis molecular systems able generate molecule and cellular compartmentalization these events paramount importance. We have use...

The actin binding protein profilin has dramatic effects on actin polymerization in vitro and in living cells. Plants have large multigene families encoding profilins, and many cells or tissues can express multiple profilin isoforms. Recently, we characterized several profilin isoforms from maize pollen for their ability to alter cytoarchitecture when microinjected into living plant cells and fo...

Three kinds of pollen taxa belonging to 3 families (Fabaceae--Trifolium spp., Brassicaceae--Raphanus spp. and Cistaceae--Cistus spp.) and commonly collected by honeybees were fed to mature male rats separately, in the form of 60 mg/animal/day for a 30-day period. The objective of this study was to investigate any positive effects or possible side effects of the use of pollen on the immune syste...

In a previous review of male gametophyte development (McCormick, 1993), it was noted that the two areas posed by Mascarenhas (1975) as fruitful areas for future research were the following. What are the differences in the two cytoplasms that determine the different cell fates of the generative and vegetative cells? And what are the functions of pollen-specific proteins? Now, 10 years later, the...