Pollen tube tubes. The presence of multiple grains of pollen has been observed to stimulate quicker pollen tube growth in some plants. The vegetative cell then produces the pollen tube, a tubular protrusion from the pollen grain, which carries the sperm cells within its cytoplasm. The sperm cells are the male gametes that will join with the egg cell and the central cell in double fertilization. The germinated pollen tube must then drill its way through the nutrient-rich style and curl to the bottom of the ovary to reach the ovule. Once the pollen tube reaches an ovule, it bursts to deliver
Bacillus spore morphogenesis and germination holin family Bacillus spore morphogenesis and germination holin family The "Bacillus" Spore Morphogenesis and Germination Holin (BSH) Family (TC# 1.E.23) is a family of proteins named after a holin in "Bacillus subtilis" described to be involved in spore morphogenesis and germination by Real et al (2005). The gene encoding this holin is "ywcE." Mutants lacking this gene or its product have spores that exhibit outer coat defects. These spores lack the characteristic striatal pattern resulting in the failure of the outer coat to attach to the underlying inner coat. Finally, the mutant spores accumulate reduced amounts of dipicolinic acid. BSH proteins average