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There is debate as to whether endospory or heterospory evolved first. Some debate centers upon the requirement of endospory to develop before heterospory. [2] Endospory is assumed to follow heterospory but it has been suggested that without endospory, early plant species dependency on water fertilization and environmental impacts on gametophytic gene expression would have reduced the chances ...
Thigmomorphogenesis (from Ancient Greek θιγγάνω (thingánō) to touch, μορφή (morphê) shape, and γένεσις (génesis) creation) the phenomenon by which plants alter their growth and development in response to mechanical stimuli, exemplifies their remarkable adaptability to fluctuating environmental conditions.
On top of the gradual growth of the plant, the image reveals the true meaning of phototropism and cell elongation, meaning the light energy from the sun is causing the growing plant to bend towards the light aka elongate. Plant growth and development are mediated by specific plant hormones and plant growth regulators (PGRs) (Ross et al. 1983). [10]
Vascular cambium with unlimited growth potential is present as well as xylem and phloem. Ancestors of the earliest seed plants as well as the first true trees. Strong monopodial growth is exhibited. Some were heterosporous but others were homosporous.
The role of strigolactones as branching inhibitor hormone was discovered because of the use of a new set of mutant plants. [5] These mutants presented excessive growth in the axillary buds, which induced their terminal stem to start branching abnormally. [5]
It was the first plant hormone proven to be a peptide. Systemin induces the production of protein defense compound called protease inhibitors. Systemin was first identified in tomato leaves. It was found to be an 18-amino acid peptide processed from the C-terminus of a 200-amino acid precursor, which is called prosystemin. [1]
Ethylene chemical structure. Ethylene signaling pathway is a signal transduction in plant cells to regulate important growth and developmental processes. [1] [2] Acting as a plant hormone, the gas ethylene is responsible for promoting the germination of seeds, ripening of fruits, the opening of flowers, the abscission (or shedding) of leaves and stress responses. [3]
Lycopodiaceae (homosporous lycophytes) split off from the branch leading to Selaginella and Isoetes (heterosporous lycophytes) about ~400 million years ago, during the early Devonian. The two subfamilies Lycopodioideae and Huperzioideae diverged ~350 million years ago, but has evolved so slowly that about 30% of their genes are still in ...