Life history and population dynamics of Atriplex triangularis

Khan, M. Ajmal; Ungar, Irwin A.

doi:10.1007/bf00044079

Cited by 37 publications

(26 citation statements)

References 28 publications

(23 reference statements)

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“…Black seeds of Atriplex centralasiatica were more sensitive to light than brown ones . Similar results have been observed in A. triangularis (Khan, & Ungar, 1986) and Suaeda salsa (Li, Liu, Khan, & Yamaguchi, 2005). Our results showed no specific light or temperature requirements for the germination of the two colours of L. glinoides.…”

Section: Discussionsupporting

confidence: 91%

Seed colour affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts

Bhatt¹,

Gairola²,

El‐Keblawy³

2016

RBT

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Heterogeneity in seeds mostly occurs due to physiological, environmental and genetic factors, and these could affect seed dormancy and germination. Therefore, the aim of our study was to assess the effect of seed colour on germination behavior. For this, both light and temperature requirements were assessed in Lotus glinoides and Lotus halophilus (Fabaceae) from the hyper-arid deserts of the United Arab Emirates. Germination was assessed in terms of both final germination level (percentage) and germination rate, as expressed by Timson's germination velocity index. Lotus glinoides produces black and yellow-colored seeds, and L. halophilus produces green and yellow seeds. Different seed lots were germinated in both light and darkness at different temperatures. Yellow seeds of the two species attained significantly lower germination, compared to black and green seeds. There was no specific light or temperature requirements for the germination of the two coloured seeds of L. glinoides; the effect of interactions between seed colour and both light and incubation temperature, were not significant on the final germination percentage. in L. halophilus, green seeds germinated significantly more in both light and darkness at lower temperatures (15/25 °C) and in light at higher temperatures (25/35 °C), compared to yellow seeds. Yellow seeds germinated faster, compared to black at 15/25 °C in L. glinoides and compared to green seeds at 15/25 °C and 25/35 °C in L. halophilus. Seed colour variation, at least in L. halophilus, could be a survival strategy that would determine the time of germination throughout the year in the unpredictable desert environment. Rev. Biol. Trop. 64 (2): 483-492. Epub 2016 June 01.

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Section: Discussionsupporting

confidence: 91%

Seed colour affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts

Bhatt¹,

Gairola²,

El‐Keblawy³

2016

RBT

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“…4 Weekly mean stem elongation (±standard error) for S. ramosissima plants exposed to different concentrations of NaCl of sediments not directly affected by the tide (Table 1). Many studies suggest that halophyte seeds respond similarly to saline stress, with a delay in the start of germination and the occurrence of germination when soil salinity is reduced (Macke and Ungar 1970;Chapman 1974;Khan and Ungar 1986;Keiffer and Ungar 1997;Katembe et al 1998;Pujol et al 2000;Silva 2000). This delay may occur when the salinity causes stress to seeds, for example reduction of germination and dormancy related to the decrease of osmotic potential (Pujol et al 2000), but do not inhibit germination when the stress conditions are alleviated, i.e.…”

Section: Discussionmentioning

confidence: 98%

“…As reported by Rubio-Casal et al (2003) for S. ramosissima and Arthrocnemum macrostachyum, low salinity may increase germination speed and rate, which increases plant density. Biotic factors may also affect survival of S. ramosissima, however-according to Khan and Ungar (1986) perennials such as P. maritima and H. portulacoides may compromise the establishment and development of seedlings of the annual halophyte Suaeda maritima. The different cohorts in the same population of S. ramosissima, as a result of delayed germination, may be caused by the seed dimorphism reported by Castroviejo (1990) and Silva (2000), with small seeds (lateral flowers) being more dormant and less salt-tolerant than large seeds (central flowers) (Philipupillai and Ungar 1984).…”

Section: Discussionmentioning

confidence: 99%

Salicornia ramosissima population dynamics and tolerance of salinity

Silva

Caldeira

Freitas

2006

Ecological Research

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Field and greenhouse studies have been conducted to clarify aspects of population dynamics and NaCl tolerance of Salicornia ramosissima J. Woods. Two populations, Varela and Verdemilho, were monitored in the field during two consecutive life cycles and aspects of their morphology and density were recorded monthly. In the laboratory seedlings were exposed to different salinity for 10 weeks and growth and mortality rate were recorded weekly. The growth of the populations differed significantly, possibly because of the different salinities of the two sampling sites and/or genetic adaptations of the two populations to the environmental conditions. The absence of a significant correlation between sediment salinity and stem elongation suggested, however, that salinity, alone was not responsible for the differences observed and was possibly associated with other factors, because of nutritional, edaphic, and microclimatic conditions. S. ramosissima did not develop well in conditions of elevated or moderate salinity; its growth was optimum at low salinity. Optimum development of S. ramosissima may, nevertheless, depend on the total number of large seeds in a population seed bank, because of their greater success in germination and germinability under stress conditions than small seeds.

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“…The crucial and controversial question, whether soil seed banks play an important role in population dynamics of halophytic shrub species in saline deserts, has been difficult to resolve because recruitment from the seed bank appeared to be a rare phenomenon. A few studies have been conducted on the seed bank dynamics of desert communities (Coffin & Lauenroth, 1989;Hegazy, 1990;Zaman & Khan, 1992), inland saline habitats (Ungar & Riehl, 1980;Khan & Ungar, 1986;Khan, 1990), and on coastal halophyte communities (Smith & Kadlec, 1983;Jerling, 1984;Aziz & Khan, 1996).…”

Section: Introductionmentioning

confidence: 98%