Priming permits seeds to slowly imbibe water at regulated rates and to begin the initial stages of germination. Hypertonic polyethylene glycol (PEG) 8000 solutions of 1.0 and 1.2 MPa at 15C improved seed germination of dusty miller (Senecio cineraria DC.). At 0.8 MPa, germination was promoted during priming. No differences in rates, span, or total germination were found among seeds primed for 1, 2, or 3 weeks with or without aeration during priming. Germination percentages of primed and nonprimed seeds were similar at 10, 15, 20, and 25C, but 42% to 81% higher for primed seed at 30 or 35C. Priming reduced days to 50% of total germination (T50) 23% to 61%, and germination spans in days 30% to 67%. Primed seeds germinated most rapidly and uniformly at 20 and 25C. No change in total germination, T50, or germination span resulted when moisture contents of primed seeds were lowered to 7.8% or seeds were held at –80C for 7 days. Primed seed performance was unchanged after storage at 5C and 52% RH for 16 weeks.
Priming or presoaking seed of common carpetgrass (Axonopus affinis Chase) and centipedegrass [Eremochloa ophiuroides Munro. (Kunz)] increased germination percentage and decreased mean time of germination (MTG) at 20, 25, and 30 °C. The effect of presoaking and priming was dependent on grass species and temperature. The optimum seed germination temperature for both of these warm-season species was 30 °C. Maximum effect on common carpetgrass or centipedegrass seeds was achieved by priming in 2% KNO3; higher concentrations did not improve germination percentage or MTG, and 4% was in some cases detrimental. Germination was higher and MTG lower at 20 and 30 °C than at 15 °C. Presoaking common carpetgrass and centipedegrass seeds was the most efficient seed enhancement treatment for germination at 30 °C.
Fever tea (Lippiajavanica) is one of the important medicinal plants belonging to the Verbenaceae family. The first objective of this investigation was to study the propagation of fever tea using stem cuttings. The main variables studied were cutting position, rooting media and rooting hormone. The germination requirement of fever tea seed is also not known. Therefore, the second objective was to investigate the ideal seed germination temperature and light combinations. Germination was tested at constant temperature regimes (15, 20, 25 and 30 °C) with a continuous light or dark period and at alternate temperatures of 20/30 °C and 16/8 hour (light/dark) combinations, respectively. For the stem cutting investigation, sampling was done every 5, 10, 15, and 20 days from plant establishment. Apical cuttings took less time to root than basal cuttings regardless of growing medium. Response of cuttings to rooting hormone was growing medium-related. With rooting hormone, it took 10 days to root most of the apical cuttings, whereas basal cuttings showed more roots in 15 to 20 days after plant establishment. Cuttings in sand took 5 days longer to root than in pine bark, regardless of rooting hormone. Therefore, for quicker establishment of fever tea stem cuttings, rooting hormone and pine bark should be used for propagation of both apical and basal cuttings. In the germination investigation, it was found that fever tea seeds are positively photoblastic. Regardless of temperature, seeds failed to germinate in continuous darkness. The germination percentage was improved at continuous or alternating temperatures above 20 °C with continuous light. However, the germination percentage decreased with alternating light and dark treatments.
seed germination temperature for all three species was 15 °C at which the maximum germination percentage and germination rate were achieved without any pretreatment indicating that there was no dormancy either in current-year seeds (three months stored
the seed age and storage conditions are unknown ( Wang et al., 2013 ). The germination temperature tested during this study (20 °C) may not be optimal. To find the optimum temperature for Pulsatilla seed germination, temperatures ranging between 20
, origin, and germination rates without salt treatment and under salt stress, absolute decrease (AD), inhibition index (II), relative salt tolerance (RST), and salt tolerance index (STI). Determination of optimal seed germination temperature and salt
germination temperatures have been reported for other Vaccinium spp. Baskin at al. (2000) reported 82% and 73% average germination rates for nonstratified seeds of European blueberry and lingonberry ( Vaccinium vitis-idaea L.), respectively, with a 25/15 °C