Effects of maternal light environment on germination and morphological characteristics of Sicyos deppei seeds

Abstract

The effect was studied of sunlight and far‐red (FR) light during seed development, on seed quality and germination of Sicyos deppei G. Don. Seeds exposed to FR during development were lighter in colour and their weight, size and water content were significantly lower. Less than 10% of non‐scarified freshly harvested seeds germinated. Scarified, freshly harvested seeds developed under sunlight had a partially negative photoblastic response; both red (R) and FR light inhibited germination. The highest and fastest germination occurred in darkness, probably due to the effect of the high photon flux densities on the phytochrome during seed development. Scarified seeds ripened under FR light, germinated well in FR light and in darkness, but R light inhibited germination. After 6 months of storage, the permeability of S. deppei seeds increased, the partially negative photoblastic response was lost and germination of scarified seeds increased. Specifically, in seeds developed under FR, germination in darkness was faster than for the other light treatments, but slow in darkness for seeds developed under sunlight. The physiological and morphological heteroblastic responses in S. deppei probably extend its seed germination and seedling recruitment periods.

Effects of seed maturation time and dry storage on light and temperature requirements during germination in invasive Prosopis juliflora

“…Similarly, freshly harvested seeds of the weedy Sicyos deppei developed under sunlight had a partially negative photoblastic response; both red and far-red light inhibited germination. After 6 months of storage, the seed permeability increased and the partially negative photoblastic response was lost (Orozco-Segovia et al, 2000). The need for high temperature and light to achieve greater germination in fresh seeds of P. juliflora was significantly reduced after seed storage.…”

“…It has been reported that fresh seeds usually germinate under specific narrow range of conditions, but such conditions gradually become wider as a result of seed storage (Gutterman et al, 1998;Orozco-Segovia et al, 2000;Qaderi et al, 2003). In the desert herb Plantago coronopus, seeds stored for 2 months germinated under a narrow range of lower temperatures (5-15 1C), but germinated under a wider range of high temperatures (15-30 1C) when stored in their inflorescences under natural desert habitat conditions for 1 year (Gutterman et al, 1998).…”

“…Similarly, several studies have reported the increase in germination after dry seed storage (e.g., Allen and Meyer, 2002;El-Keblawy and Al-Ansari, 2000;Gutterman, 2000;Hidayati et al, 2002), but few studies examined the effect of storage on light and temperature requirements during germination (Gutterman et al, 1998;Orozco-Segovia et al, 2000;Qaderi et al, 2003).…”

Seed ecology of a Mediterranean perennial herb with an exceptionally extended flowering and fruiting season

“…In general, the germination characteristics of a seed are determined during the course of its development, and the environmental conditions experienced by parent plants during seed production and maturation can strongly influence the degree and type of dormancy in the seed (Fenner, 1985: 79; Kegode & Pearce, 1998; van Hinsberg, 1998; Orozco‐Segovia et al ., 2000). In the case of L. maritima , the environmental inhibition of germination might have been under selection, as responses of seeds to various environmental factors have a genetic basis (Baskin & Baskin, 1998: 186; Foley & Fennimore, 1998).…”

The influence of canopy, sky condition, and solar angle on light quality in a longleaf pine woodland

“…Many wavebands within the light spectrum are of biological significance, including photosynthetically active radiation (PAR) (400-700 nm) for photosynthesis and UVA/UVB (350-500) for stomatal opening and induction of phototropism (Smith 1982;Grant 1997;Hart 1998). The ratio of red (660) to far-red (730) light (R:FR) is important for the detection of competition Ballaré et al 1990) and regulation of seed dormancy and germination (Lee et al 1996;Orozco-Segovia et al 2000), stem elongation and leaf area expansion (Morgan 1981), apical dominance , and internode expansion (Morgan and Smith 1978a;Ballaré et al 1990;Grant 1997). Generally, plants respond to a decrease in R:FR by increasing leaf area and internode length in an effort to access more available light (Morgan and Smith 1978b;Smith 1981Smith , 1982.…”