Selective embryo abortion in a perennial tree-legume: a case for maternal advantage of reduced seed number per fruit

Abstract

In this study, I analyzed time-course of embryo abortion, positional bias in seed maturation and maternal costs of seed packaging in Cercis canadensis. While basal embryos experience similar rates of abortion as those in other positions during the first week of development, abortion rates peak during the second week. Head start in resource sequestration by stigmatic embryos may explain high rates of basal embryo abortion. Similar seed packaging costs and seed mass for single and multi-seeded pods suggests that maternal parent regulates pod size in accordance with seed numbers per pod investing equally in the surviving offspring. Competition during early developmental period results in the abortion of less competitive embryos allowing for optimal resource investment.

Delayed pollination and low availability of assimilates are major factors causing maize kernel abortion

“…From an evolutionary perspective, the advantage of overproduction of ovaries relative to the number of seeds set could be explained by (i) a ‘bet-hedging’ strategy in which plants could quickly adjust the number of seeds in response to unpredictable environments ( Lloyd, 1980 ; Kozlowski and Stearns, 1989 ; Burd, 1998 ; Arathi, 2011 ) and (ii) a mechanism for eliminating ovaries of low quality and survival probability, in order to efficiently invest resources in more competitive ovaries ( de Jong and Klinkhamer, 2005 ; Mena-Ali and Rocha, 2005 ; Arathi, 2011 ), especially when resources are deficient, for example, under abiotic stresses ( Ruan, 2014 ; Tardieu et al , 2014 ). This hypothesis predicts that kernel set or abortion closely relates to the amount of resources available.…”

“…However, pollen limitation is not a common occurrence in many angiosperms ( Bawa and Webb, 1984 ; Burd, 1994 ; Larson and Barrett, 2000 ; Sakai and Harada, 2001 ). Instead, post-fertilization seed abortion can frequently be induced due to limitations in the available resources ( Snow and Spira, 1991 ; Arathi et al , 1999 ; Yang et al , 2005 ; Brookes et al , 2008 ; Arathi, 2011 ), and it can become more severe under unfavorable circumstances, including drought ( Otegui et al , 1995 ; Andersen et al , 2002 ; McLaughlin and Boyer, 2004a, b ), heat ( Cheikh and Jones, 1994 ; Hays et al , 2007 ; Liu et al 2016 ), and other environmental stresses ( Andrade et al , 2002 ; Hiyane et al , 2010 ). Given the increased frequency and severity of climate-change-related stresses, seed abortion has become a central issue for food security in the 21st century ( Grassini et al , 2013 ; Ray et al , 2013 ).…”

Intervening in sibling competition for assimilates by controlled pollination prevents seed abortion under postpollination drought in maize

“…It is a common law that angiosperms produce more ovaries than final seeds, which results in unavoidable selective ovary abortion (Stephenson, 1981;Ruan et al, 2012). Evolutionarily, overproduction of ovary allows plants (a) to quickly adjust the seed number in response to an unpredictable environment (Lloyd, 1980;Kozlowski & Stearns, 1989) and (b) to efficiently invest limited resources in more competitive progenies (de Jong & Klinkhamer, 2005;Mena-Ali & Rocha, 2005;Arathi, 2011). In this study, we demonstrated that a short-term postpollination drought induced irreversible abortion of apical kernels even if sufficient irrigation was subsequently applied (Figure 3).…”

Supplemental and Synchronized Pollination May Increase Yield in Cacao

“…Here, weak sink effects may be underlying the lower fruit set rates during times of presumably unlimited resources and may be further exacerbated by low flowering intensity during the earlier pollination weeks. When flowering intensity is low, increased pollination intensity appears advantageous to fruit set, possibly by establishing a stronger resource sink (e.g., an increased number of developing cherelles) driving the internal plant physiological processes (i.e., assimilate production and/or remobilization, hormone production) that support the fertilization success of subsequently pollinated flowers (Arathi, 2011).…”