Effects of Seed Reservation-oriented Cultivation on Seed Quality and Disease and Insect Damages of Maca

[Objective] The aim was to explore the effects of cultivation and seed reservation methods on quality and disease/insect damages of maca seed in cold highland areas,providing scientific references for cultivation and seed reservation and planning of maca vareity.[Method] Yellow,purple and black maca were selected and cultivated in the region with an elevation of 3 000 m to be experimental materials and cultivation and seed reservation methods were as follows：maca seed reservation in situ,seed reservation in original soils maca grown after selection of maca balls,and seed reservation in the region with an elevation of 2 700 m after selection of maca ball,seed reservation in greenhouses in the region with an elevation of 2 400 m after selection of maca ball,and growing selected balls in greenhouses and transplanting to the farmlands with an elevation of 2 400 m.[Result] The cultivation and seed reservation methods had significant or extremely significant effects on maca phenological phase;maca in different colors were treated by different cultivation and seed reservation methods,showing insignificant effects on disease and insect damages.[Conclusion] It can be concluded that the selected maca balls stored for 15 d as per the method grown in the region with an elevation of 2 700 m will improve seed quality and reduce disease or insect damages.

Seed Size as Key Factor in Germination and Seedling Development of Copaifera langsdorffii(Fabaceae)

Seed size is a plastic trait of the plants that directly affect seed germination and seedling recruitment. This study aimed to investigate the relationship between seed size, seed germinability and seedling performance of Copaifera langsdorffii by testing four hypotheses: 1) larger seeds have higher germination percentage;2) smaller seeds require less time to germinate and for initial development of the seedlings;3) larger seeds produce more vigorous seedlings and 4) seed size negatively affects seedling root/shoot ratio. In 2011, we selected 30 individuals of C. langsdorffii from which 300 seeds were randomly collected in the plant canopy. All these seeds were weighted and placed in germination tray using vermiculite as substrate. Seed germinability and initial development of seedlings were monitored daily until cotyledons fell. Small seeds have higher germination percentage and germinate faster when compared to large seeds. Nonetheless, seedlings originated from larger seeds have longer development times, resulting in more vigorous seedlings. In addition, seedlings originating from small seeds allocate proportionally greater amount of resources to roots when compared to larger seeds. The fact that small seeds have higher germination percentage and faster germination favors the colonization of transient habitats. However, larger seeds produce more vigorous seedlings, favoring the seedling establishment in more stable habitats. Thus, we argue that high variability in seed size of C. langsdorffii favors its widespread geographic distribution.

Seed,germination,and seed-reserve traits differ along an altitudinal gradient

Turkish red pine(P inus brutia Ten.), an important pine species for afforestation studies, grows at a wide range of altitudes in the eastern Mediterranean area. Seeds from low(0–400 m a.s.l.), mid(400–800 m) and high(800–1000 m) altitudinal gradients were collected to assess the effects of these gradients on morphological traits(seed length, seed width, 100-seed weight), germination variables(germination percentage and mean germination time), and 10biochemical variables related to seed reserves. Relationships among these variables were examined with a correlation analysis. Seeds from low and high altitudes had significantly higher 100-seed weight, higher percentage germination but longer germination times and higher total oil and reducing sugars contents. Seeds from mid altitudes had higher carotenoid and soluble phenolics contents. Among the examined biochemical variables, only flavonoid content did not differ among the altitude gradients. The main fatty acids in seeds samples(linoleic, oleic, palmitic and stearic acids) were also influenced by the altitude gradients. Oil and total reducing sugars contents were positively correlated with germination percentage, and carotenoid content was negatively correlated with germination percentage. Our results confirmed that seed and germination variables, including the reserve composition varied significantly among the altitudinal gradients.

Factors influencing seed reserve utilization during seedling establishment in maize inbred lines

Strong seedlings are essential for high yield.To explore the foundation of strong seedlings,we investigated various factors influencing the conversion and distribution of seed storage reserves during seedling establishment in maize inbred lines.Three maize inbred lines were used to explore the effects of seed size,seed vigor,illumination duration,temperature,water content,and salt concentration of the seedling medium on the utilization of seed storage reserves during seedling establishment.The results showed that the conversion rate of small seeds was 3.69 to 17.71%higher than that of large seeds.Moreover,prolonged illumination time was conducive to the formation of strong seedlings.However,low temperature,drought stress and salt stress reduced the conversion rate of seed storage reserves and increased the root/shoot ratio.These results could be used to guide field management during seedling emergence and develop improved germplasm with a high conversion rate of seed storage reserves.

The Association between Germination Vigour and Biochemical, Physiological, Subcellular Changes in Bambara Groundnut Seeds after Seed Scarification

Seed storage reserves and organelles after scarification(chemical,mechanical,control)of bambara groundnut with different seed coat colours(cream,light brown and brown)were examined in relation to germination vigour.Seed storage proteins,oil and sugar content,starch granules and protein bodies,germination vigour index(GVI)and mean germination time(MGT)were measured.There were significant(p<0.05)effects of seed scarification on protein body diameter,seed oil content and sugar content.Chemical scarification resulted in seeds having larger starch granules,followed by the control and mechanical scarification that resulted in seeds having smaller starch granules.Mechanical scarification had the highest(p>0.05)protein density,followed by chemical scarification and control seeds that had the lowest protein density.Seeds from the control had the highest oil content,followed by seeds from mechanical scarification and seeds from chemical scarification that had the lowest oil content.Seeds from the control and chemical scarification had larger diameter of protein bodies and sugar content.Seed coat colour significantly(p<0.05)influenced the area and diameter of protein bodies,starch granule area,seed sugar content.Brown seeds produced larger protein bodies and the highest oil content,while light brown seeds had larger area of starch granules and the highest sugar content.Seed storage reserves had an influence on bambara groundnut germination vigour.While favouring dark coloured seeds such as light brown and brown,bambara groundnut seed users should adapt chemical seed scarification to enhance germination vigour of this crop.