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REDIRECTED ENERGY. "In theory, the progressive senescence of existing somatic tissues reflects the minimum energy spent on maintenance of these tissues - energy that is thus available for seed development." https://lnkd.in/dNWP3KD View in LinkedIn

SOMATIC DECLINE. "After fertilization and as the seeds mature, the somatic tissues of the plant become increasingly senescent. However, if reproduction is delayed, anatomically definable vegetative meristems can initiate in axils of older leaves." https://lnkd.in/dNWP3KD View in LinkedIn

SENESCENCE SYNDROME. "However, photosynthetic organs are rich in nutrients, which would be lost without mechanisms that salvage them before the obsolete organs are cast off. We refer to this salvage process as the senescence syndrome." https://lnkd.in/dNWP3KD View in LinkedIn

ANCIENT PROCESS. "It is not surprising that plants have evolved mechanisms for dealing with obsolete organ systems. The shedding of leaves by the process of abscission is a very ancient trait - fossils from as early as the Devonian period (i.e., -400 million years ago) show evidence of abscission scars." https://lnkd.in/dNWP3KD View in LinkedIn

MATURE LEAVES. "In principle, natural selection is unlikelyto favor excessive energy investment in the maintenance of such an organ past the average time of its usefulness to the plant, because such an investment may compromise reproductive success." https://lnkd.in/dNWP3KD View in LinkedIn

LEAF FALL. "Timing of leaf abscission is an important trait for biomass production and seasonal acclimation in deciduous trees. The signaling leading to organ separation, from the external cue (decreasing photoperiod) to ethylene-regulated hydrolysis of the middle lamellae in the abscission zone, is only poorly understood." https://lnkd.in/dTkfjMD View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend on the subject of autumn leaf drop. As plants harvest the invested nutritional value from autumn leaves before they drop them, there is a hive of genetic and metabolic activity within the forest; large numbers genes are turned on and off, triggered by environmental cues, while leaf molecules are being shunted to storage tissues to wait for the spring growth initiative. A busy time for our friends. View in LinkedIn

MASTER CONTROL. "Observations are consistent with the existence of master regulatory systems that can determine the timing of the senescence syndrome." https://lnkd.in/dNWP3KD View in LinkedIn

COMPLEXITY AND CONTROL. "The overall process of the senescence syndrome may be very complex, but it is still worth considering whether there are definable regulatory systems that have an overriding influence on the timing of the conversion from photosynthetic to salvage programs." https://lnkd.in/dNWP3KD View in LinkedIn

UPWARDLY MOBILE. "The evolution of multi-cellularity is characterized by the integration of lower-level units into higher-level entities, and hence is associated with a transition in individuality." http://rspb.royalsocietypublishing.org/content/early/2011/12/05/rspb.2011.1999.short View in LinkedIn