Overcoming dormancy and determining optimal temperature for slender serradella seed germination

Abstract

-The objective of this study was to identify the most efficient method for overcoming coat-imposed dormancy and determine the optimal germination temperature for Ornithopus pinnatus seeds. Treatments to overcome dormancy were: intact seeds; immersion in hot water at 60 ºC, followed by soaking in the same water (unheated)/24 h; immersion in hot water at 90 ºC, followed by soaking in the same water (unheated)/24 h; mechanical scarification; chemical scarification, H 2 SO 4 /5 min; and chemical scarification, H 2 SO 4 /10 min. Percentages were calculated for germinated, abnormal, dormant, and dead seeds. Optimal germination temperatures were calculated using eight constant temperatures (0, 5, 10, 15, 20, 25, 30, and 35 °C), with 8 h of light and 16 h of darkness. Germination rate, frequency, and synchronization index of germination were used as parameters to establish optimum temperature for germination. A completely randomized experimental design was used, with twelve repetitions of 100 seeds per treatment. Data obtained were subjected to analysis of variance and Tukey's test at a 5% significance level. O. pinnatus seeds exhibit dormancy caused by the seed coat's impermeability to water. Mechanical scarification was efficient in promoting seed germination. The species is stenothermal, meaning it cannot tolerate significant temperature variations. The germination rate of seeds was linearly dependent on temperature. Synchronization of the germination process is greater in the optimum temperature range, established between 15 and 20 °C.

A novel approach for improving germination rate of Mucuna bracteata

“…As per the findings Yazdanpanah et al (2012) of a high percentage of germination is achieved through scarification of seeds with sandpaper (65%). The same observations were also made by Sanjana and Jeya (2013); Lopes et al (2015), who reported that the seeds that were mechanically scarified exhibited very high germination percentage compared with any other seed treatment.…”

Investigating Seed Dormancy in Pinus bungeana Zucc. ex Endl.: Understanding the Contributions of Enclosing Tissues and Temperature on Germination

“…This temperature variation is called thermos-inhibition, which is characterized by the absence of germination when the temperature is slightly above the optimum conditions [36]. Germination inhibition by high temperatures (25 • C-30 • C) has been observed in other species, such as Spinacia oleracea L. [17,18], Ornithopus pinnatus [19], and Myrsine parvifolia [20], and the seeds of these three species have also shown higher final germination at temperatures of 15 • C and 20 • C, while significantly lower germination occurred at 25 • C and 30 • C.…”

“…For example, either no germination or extremely low germination was observed at 25 • C and 30 • C, while high final germination was obtained when seeds were incubated at lower temperatures of 15 • C and 20 • C for species such as Pinacia oleracea L. [17,18], Ornithopus pinnatus (Mill.) Druce [19], and Myrsine parvifolia A. DC. [20], and coniferous species of Pinus halepensis Miller and Pinus brutia Tenore [21].…”

Effects of Climate Change on Weeds and Invasive Alien Plants in Sri Lankan Agro-Ecosystems: Policy and Management Implications

“…Moreover, Javaid et al (2010) reported of prolonged seed dormancy in P. hysterophorus with increasing temperature. Lopez et al (2015) reported that the germination process of plant species is generally synchronized within the optimum temperature range. These results indicate that IAPs such P. hysterophorus could enhance its persistence in the environment and opportunity for developing into new invasions by temporal variations in seed germination due to non-synchronized breaking of seed dormancy.…”