Corn silk is a common ''Stigma maydis'', the shiny, thread-like, weak

fiber Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorpora ...

s that grow as part of

ears An ear is the organ that enables hearing and, in mammals, body balance using the vestibular system. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consists o ...

of corn (

maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The ...

); the tuft or

tassel A tassel is a finishing feature in fabric and clothing decoration. It is a universal ornament that is seen in varying versions in many cultures around the globe. History and use In the Hebrew Bible, the Lord spoke to Moses instructing him to ...

of silky fibers that protrude from the tip of the ear of corn. The ear is enclosed in modified leaves called husks. Each individual fiber is an elongated

style Style is a manner of doing or presenting things and may refer to: * Architectural style, the features that make a building or structure historically identifiable * Design, the process of creating something * Fashion, a prevailing mode of clothing ...

, attached to an individual ovary. The term probably originated sometime between 1850 and 1855.

Development

Up to 1000

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the '' integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the ...

s (potential kernels) form per ear of corn, each of which produces a strand of corn silk from its tip that eventually emerges from the end of the ear. The emergence of at least one strand of silk from a given ear of corn is defined as growth stage R1, and the emergence of silk in 50% of the plants in a corn field is called "mid-silk". The silk lengthens from the basal ovules during the 10 to 14 days previous to growth stage R1; this is due to a change of shape of existing cells rather than their replication. The elongation progresses at 1.5 inches per day at first but gradually slows as the full length is approached. Elongation of a corn silk strand stops soon after a grain of pollen is captured or due to senescence of the silk 10 days after its emergence. If an ovule is successfully fertilized, the corn silk will detach from it two or three days later. Otherwise, the silk will remain attached indefinitely, and fertilization remains possible (with decreasing chances of success) for 10 days after silk emergence. For this reason, it is possible to sample developing ears of corn from a field, husking them gently with a sharp knife, then shaking them to assess the progress of pollination based on how much of the corn silk falls away.

Function

Corn silk is part stigma and part

, providing a female flower surface to which pollen grains can adhere and defining the path through which the pollen must travel. The stigma is the very tip of the corn silk, which has a larger number of hairs to help pollen to adhere to it. Kernel formation in the cob requires

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...

of the external corn silk by wind or insects. Usually several grains of pollen adhere, but only one will successfully participate in

fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

of the ovule to form a corn kernel. For the pollen grain, the male

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the ...

, to transmit its genetic material to the ovule, it must germinate and form a pollen tube that extends down nearly the full length of the corn silk strand. Typically 400 to 600 kernels are successfully formed in this way. The pollen tube extends at a rate of over 1 centimeter per hour, requiring only 24 hours to create a foot-long pathway within the intercellular space of the corn silk through which the sperm cells (the

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s) pass to join the female gametophyte within the ovule. The pollen tube is produced by the single

vegetative cell A somatic cell (from Ancient Greek σῶμα ''sôma'', meaning "body"), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Such cells compo ...

in the pollen grain, which passes its cytoplasm, nucleus and two sperm cells into the tube. The tube extends itself at the apex only, in an actin polymerization dependent process, and the direction in which the apex progresses responds to

cyclic AMP Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal tra ...

levels, including cAMP cyclization by a pollen signalling protein (PSiP). Corn silk can control the types of pollen that an ear of corn will accept through expression of certain forms of the Gametophyte Factor 1 gene. Many races of popcorn, of the everta type, will greatly slow the development of pollen tubes from any pollen that does not carry a similar form of Ga1-S or Ga1-M, thereby preventing the ingression of genes (natural or engineered) from other types of corn. The popcorn remains free to donate its genes via its own pollen to other types of corn. The effectiveness of this restriction can be measured by planting the popcorn beside purple dent corn; the xenia effect would cause the formation of purple

aleurone Aleurone (from Greek ''aleuron'', flour) is a protein found in protein granules of maturing seeds and tubers. The term also describes one of the two major cell types of the endosperm, the aleurone layer. The aleurone layer is the outermost layer of ...

s if kernels permitted themselves to be fertilized by pollen from outside the group.

Organic farmer Organic farming, also known as ecological farming or biological farming,Labelling, article 30 o''Regulation (EU) 2018/848 of the European Parliament and of the Council of 30 May 2018 on organic production and labelling of organic products and re ...

s are pursuing the transfer of some of these mechanisms into non-popcorn strains for purposes of preventing inadvertent pollination by GMO corn, which under U.S. regulations can cause their product to be rejected as organic corn, and for which they have no recourse against GMO growers.

Pathology

The moisture of freshly emerged corn silk sometimes attracts insects, which can cause silk clipping, which can interfere with kernel formation.

Applications

Corn silk contains a variety of pharmacologically-active compounds and as such is used in many types of folk medicine, including as a

diuretic A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics i ...

and as an inhibitor of

melanin Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the amino ...

production. In many studies, it is proven that corn silk has antioxidant and healthcare properties. Also, it acts as a diuretic agent that reduces hyperglycemia, antidepressant, and as an anti-fatigue agent. Corn silk is also used in teas and supplements for treating urinary problems. The antioxidant and hematoprotective effect of corn silk protein

hydrolysate Hydrolysate refers to any product of hydrolysis. Protein hydrolysate has special application in sports medicine because its consumption allows amino acids to be absorbed by the body more rapidly than intact proteins, thus maximizing nutrient delive ...

have been experimentally demonstrated. Potential antioxidant peptides in the hydrolysate have also been identified.Ong, J.-H.; Koh, J.-A.; Cao, H.; Tan, S.-A.; Abd Manan, F.; Wong, F.-C.; Chai, T.-T. Purification, Identification and Characterization of Antioxidant Peptides from Corn Silk Tryptic Hydrolysate: An Integrated In Vitro-In Silico Approach. Antioxidants 2021, 10, 1822, doi:https://doi.org/10.3390/antiox10111822.

Development

Function

Pathology

Applications

References

See also