Editing Calcium deficiency (plant disorder) (section)

==Symptoms==
[[File:Blossomendrot.jpg|thumb|Blossom end rot on a grape tomato]]
Calcium deficiency symptoms appear initially as localized tissue [[necrosis]] leading to stunted plant growth, [[necrotic]] [[Leaf#Terminology|leaf margins]] on young leaves or curling of the leaves, and eventual death of [[Bud#Types of buds|terminal buds]] and [[Root#Root structure|root tips]]. Generally, the new growth and rapidly growing tissues of the plant are affected first. The mature leaves are rarely if ever affected because calcium accumulates to high concentrations in older leaves.<ref>{{Cite journal|jstor= 2431629 |title=The Symptoms of Calcium Deficiency in Plants |journal=The New Phytologist |volume=80 |issue=1 |author=E. W. Simon|pages=2–4|year=1978 |doi=10.1111/j.1469-8137.1978.tb02259.x |doi-access=free }}</ref> Calcium deficiencies in plants are associated with reduced height, fewer nodes, and less leaf area.<ref>{{Cite journal|last1=Chen|first1=Chang-Tsern|last2=Lee|first2=Ching-Lung|last3=Yeh|first3=Der-Ming|date=2018-06-01|title=Effects of Nitrogen, Phosphorus, Potassium, Calcium, or Magnesium Deficiency on Growth and Photosynthesis of Eustoma|url=http://hortsci.ashspublications.org/content/53/6/795|journal=HortScience|language=en|volume=53|issue=6|pages=795–798|doi=10.21273/HORTSCI12947-18|issn=0018-5345|doi-access=free}}</ref>

Crop-specific symptoms include:{{Citation needed|date=February 2008}}

; [[Apple (fruit)|Apple]] : '[[Bitter pit]]' – fruit skins develop pits, brown spots appear on skin and/or in flesh and taste of those areas is bitter. This usually occurs when fruit is in storage, and [[Bramley (apple)|Bramley apple]]s are particularly susceptible. Related to [[boron deficiency (plant disorder)|boron deficiency]], "water cored" apples seldom display bitter pit effects.
; [[Cabbage]], [[lettuce]] and [[brussels sprout]]s :There is some evidence that plants like lettuce are more likely to experience tipburn (burned edges of leaves) if they're experiencing a deficiency of calcium.<ref>{{Cite journal|date=1998-08-31|title=Causes of the tipburn disorder in leaves of vegetables|journal=Scientia Horticulturae|language=en|volume=76|issue=3–4|pages=131–147|doi=10.1016/S0304-4238(98)00153-8|issn=0304-4238|last1=Saure|first1=M.C.}}</ref><ref>{{Cite journal|last1=Barta|first1=Daniel J.|last2=Tibbitts|first2=Theodore W.|date=1991-09-01|title=Calcium Localization in Lettuce Leaves with and without Tipburn: Comparison of Controlled-environment and Field-grown Plants|journal=Journal of the American Society for Horticultural Science|language=en|volume=116|issue=5|pages=870–875|issn=0003-1062|doi=10.21273/JASHS.116.5.870|pmid=11538112|doi-access=free}}</ref> 
; [[Carrot]] : '[[Cavity spot]]' – oval spots develop into craters which may be invaded by other [[Pathogen|disease-causing organisms]].<ref>{{cite web|url= http://www.uga.edu/vegetable/carrot.html|title= The University of Georgia College of Agricultural and Environmental Sciences, Department of Horticulture - Carrot|author= Dr. Harry A. Mills|pages= 3–4|access-date= 2008-02-28|archive-url= https://web.archive.org/web/20080225004038/http://www.uga.edu/vegetable/carrot.html|archive-date= 2008-02-25|url-status= dead}}</ref>
; [[Celery]] : Stunted growth, central leaves stunted.
; [[Tomato]]es and [[capsicum|pepper]]s:'Blossom end rot' – Symptoms start as sunken, dry decaying areas at the blossom end of the fruit, furthest away from the stem, not all fruit on a truss is necessarily affected. Sometimes rapid growth from high-nitrogen fertilizers may exacerbate blossom end rot. Water management and preventing water stress is key to minimizing its occurrence.<ref name=":0">{{Cite web|url=https://ucanr.edu/sites/placernevadasmallfarms/files/86509.pdf|title=Managing Blossom-End Rot in Tomatoes and Peppers|last=Fake|first=Cindy|date=March 2010|website=Horticulture and Small Farms Advisor, Nevada & Placer Counties|publisher=UCANR}}</ref> Although it was once common knowledge that blossom end rot was caused by calcium deficiencies, there are also other proposed causes.<ref>{{Cite journal|last1=Rached|first1=Moalla|last2=Pierre|first2=Baldet|last3=Yves|first3=Gibon|last4=Matsukura|first4=Chiaki|last5=Ariizumi|first5=Toru|last6=Ezura|first6=Hiroshi|last7=Fukuda|first7=Naoya|date=2018|title=Differences in Blossom-end Rot Resistance in Tomato Cultivars is Associated with Total Ascorbate rather than Calcium Concentration in the Distal End Part of Fruits ''per se''|url=https://www.jstage.jst.go.jp/article/hortj/advpub/0/advpub_OKD-150/_article/-char/ja/|journal=The Horticulture Journal|language=en|volume=87|issue=3|pages=372–381|doi=10.2503/hortj.OKD-150|issn=2189-0102|doi-access=free}}</ref><ref>{{Cite journal|last1=Vinh|first1=Tran Duy|last2=Yoshida|first2=Yuichi|last3=Ooyama|first3=Mitsuo|last4=Goto|first4=Tanjuro|last5=Yasuba|first5=Ken-ichiro|last6=Tanaka|first6=Yoshiyuki|date=2018|title=Comparative Analysis on Blossom-end Rot Incidence in Two Tomato Cultivars in Relation to Calcium Nutrition and Fruit Growth|journal=The Horticulture Journal|language=en|volume=87|issue=1|pages=97–105|doi=10.2503/hortj.OKD-114|issn=2189-0102|doi-access=free}}</ref><ref>{{Cite journal|date=2014-07-22|title=Why calcium deficiency is not the cause of blossom-end rot in tomato and pepper fruit – a reappraisal|journal=Scientia Horticulturae|language=en|volume=174|pages=151–154|doi=10.1016/j.scienta.2014.05.020|issn=0304-4238|last1=Saure|first1=Max C.|doi-access=free}}</ref>