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Urediniospores of 11 Milesina species. a Milesina blechni on Struthiopteris spicant b Milesina blechni on Struthiopteris spicant, cracked spore with released plasma, germ pores scattered c Milesina carpatica on Dryopteris filix-mas d Milesina exigua on Polystichum braunii, smooth surface e Milesina exigua on Polystichum braunii, smooth surface, plasma-free spore, germ pores bipolar f Milesina ...
Uredo is a genus of rust fungi: long considered incertae sedis in the order Pucciniales, but now placed in the family Pucciniaceae. [2] This long-established genus, together with the closely-related Uromyces (which some authorities consider to be synonymous), give their names to "uredo-type" fungal spore structures such as "urediniospore" and uredinium".
In most seed plants, especially woody types, the endodermis is present in roots but not in stems. The endodermis helps regulate the movement of water, ions and hormones into and out of the vascular system. It may also store starch, be involved in perception of gravity and protect the plant against toxins moving into the vascular system.
The discovery of the Casparian strip dates back to the mid-19th century, and advances in the understanding of the endodermis of plant roots. [15] In 1865, the German botanist Robert Caspary first described the endodermis of the root of plants, found that its cell wall was thickened, and named it Schuchtzscheide.
JA travels through plants via the phloem, and accumulates in vascular tissue. [6] JA acts as an intracellular signal in order to promote responses in distal tissues. [ 6 ] The perception of jasmonate in distal responding leaves is necessary for recognition of the transmissible signal that coordinates responses to wounding stress. [ 5 ]
The second more recent hypothesis is that spores were an early predecessor of land plants and formed during errors in the meiosis of algae, a hypothesized early ancestor of land plants. [ 18 ] Whether spores arose before or after land plants, their contributions to topics in fields like paleontology and plant phylogenetics have been useful. [ 18 ]
The dark horizontal lines on silver birch bark are the lenticels. [1]A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of gymnosperms and dicotyledonous flowering plants. [2]
This release of amylase is considered to be the most important and sole function of the aleurone layer. This effect is inhibited by the plant hormone abscisic acid , which keeps the seed dormant. After completing this function, the aleurone cells in the developing seed undergo apoptosis .