Collection Age and Seed Mass Influence Germination and Seedling Growth in Midwestern White Spruce Accessions

Stored tree seed collections are essential resources for seedling production and conserving unique germplasm. As stored seeds age, however, seed viability and seedling vigor can decline. This study tests how age and seed mass correspond to germination dynamics and seedling vigor in four white spruce collections from the upper midwestern Unites States. Using two seedling growth experiments, this study demonstrates that white spruce seeds stored for >30 years have low seed viability and slower seedling growth rates compared with seeds from more recent (≤10 years) white spruce collections. Seed mass also predicted seedling growth rate regardless of collection age, suggesting larger seeds from older collections generate faster growing seedlings. Study Implications: Efficient use of stored tree seeds saves nursery managers time and resources. White spruce is a collection priority, but management needs to know how seed viability and seedling vigor decline during storage. Diminished germination and seedling growth after >30 years in storage suggests older collections are most appropriate for germplasm conservation and underscore the importance of testing stored seed prior to nursery production. For collections stored <10 years, larger seeds germinate more readily than smaller seeds and produce faster growing seedlings. For older collections, seed mass does not correspond with germination, but seedling growth rate positively correlated with seed mass.

Mechanical scarification technique breaks seed coat-mediated dormancy in wild oat (Avena fatua)

Wild oat is a herbicide resistance-prone global weed species that causes significant economic losses in dryland and horticultural agriculture. As a result, there has been a significant research effort in controlling this species. A major impediment to this research is the seed coat-mediated dormancy of wild oat, requiring a labor-intensive incision or puncturing of the seed coat to initiate seed germination. This study defines the most efficient settings of a mechanical thresher to overcome wild oat seed dormancy and then validates these settings using multiple populations collected from the Western Australian grain belt. We also compare the effects of rapid mechanical scarification and known germination stimulus tactics such as scarification with sulfuric acid (H2SO4), partial endosperm removal, sandpaper scarification of the seed coat, and immersion in sodium nitroprusside (NO donor SNP) solution on wild oat seedling growth rate. Threshing treatment of 1,500 rpm for 5 s provides equivalent germination compared with manually puncturing individual wild oat seeds, with no difference in seedling relative growth rate. The mechanical scarification of seeds using the thresher resulted in greater germination (66%) than H2SO4 scarification (0%), partial endosperm removal (10%), sandpaper seed coat scarification (25%), and exposure to NO donor SNP (34%). This study demonstrates that the physical dormancy of wild oat can be rapidly overcome using a commercially available mechanical thresher.

Germination and seedling growth in Afzelia africana Sm. ex. Pers.

This study determined the best pre–treatment regime required for germination of the seeds of Afzelia africana Sm.Ex.Pers. and also provided information on the early growth parameters of the plant seedlings. Seeds of A. africana were collected from Obafemi Awolowo University, Ile – Ife (Lat 7° 32'N, Long 4° 31'E) and authenticated at the IFE-herbarium. One hundred and twenty five (125) seeds were sown per treatment (n=5 with 5 replicates and 5 repeats). Five (5) seeds each were sown in small petri dishes, without pre–treatment (control), or treated by subjecting to mechanical scarification and chemical scarification using Tetraoxosulphate (VI) acid (H SO ) and Trioxonitrate (V) acid (HNO3 ) for germination studies. Germination counts were made at an interval of 2 days. For the six different pre–treatments, five seedlings per plastic bowl were transferred into soil in a total of twenty plastic bowls laid out in a randomized design and their growth monitored for 40 weeks. Results showed that pre–treatment of seeds with mechanical scarification gave the highest percentage germination. Significant differences (P ˂ 0.05) occurred in the shoot height and in the number of leaves between 4 and 12 weeks of growth. The study established that pre–treatment with mechanical scarification was the best for uniform germination of seeds of the plant. This study has provided alternative means of pretreating A. africana seeds apart from using H2SO4 – the first to subject seeds to mechanical scarification and 2 4 chemical scarification using HNO3 , in addition to providing information on the germination parameters and the seedling growth rate of Afzelia africana. Key words: Propagation, Growth, Acid, Scarification

Komposisi Jenis Tumbuhan dan Analisis Sebaran Langkap (Arenga obtusifolia Mart.) di Taman Nasional Ujung Kulon

Langkap (Arenga obtusifolia) is one of the species of the Arenga clan, which has a wide distribution in Ujung Kulon National Park (UKNP). The aim of study was to determine the pattern of spreading langkap in order to support the management of Javan Rhino habitat. The vegetation analysis method used is a combination method between the line method and the path method. Langkap is the dominant species in UKNP at the sapling growth rate, with a density of 480-624 individuals/ha and INP value of 61.47% -78.30%, while the catch density at seedling growth rate is 900- 2,200 individuals/ha with INP value of 21.31% -49.41%. The standard Morisita coefficient value of langkap in each research block and growth rate is obtained in the range of values (-0.32) - 0.51, the spreading pattern shows a clustered spread pattern (Ip> 0) and uniform (Ip <0). The tendency of langkap domination in the research block can be seen from the ratio of catch density compared to the total density or its relative density at various growth rates. This shows that in the dominant catchment area there is a reduction in the density of plants other than langkap, especially the Javan Rhino feed plants.

Impact of Seed Size on the Seedling Vigour, Dry Matter Yield and Oil Content of Jatropha (Jatropha curcas L.)

Seed size is a trait of the plant that affects seed germination and seedling survival. This study aims to assess the growth response of J. curcas to different seed sizes. A pot experiment was conducted to evaluate the effects of J. curcas seed sizes on the seedling vigour and seed component. The seeds were fractioned into three sizes visually into: large, medium and small and by 1000 seeds weight (SW). Seedling vigour was assessed by: germination % (G%), seedling length cm (SL), seedling vigour index, SVI, seedling growth rate, SGR, and speed of germination, SOG as well as proportion of cake, shell and oil content (OC) expressed as% of the seed. Results obtained shows that G% and the SOG were not affected by seed sizes but by other factors within the seed. However, seedling vigour expressed as SL, SVI and SGR increased significantly (P &le; 0.05) with increase in seed sizes. Proportion of cake, shell and oil component of J. curcas seeds increased with increasing seed sizes while 60% of the seed is made up of the cake from where the oil is extracted. Dry matter yield, DMY significantly (P &le; 0.05) increased with increase in seed size from 6.41 g/plant in large seeds to 2.61 g/plant in small seeds. There is positive and strong significant correlation between, SW and DMY (r = 0.91**), yield increase (r = 0.82**), OC (r = 0.85**), % cake (r = 0.94**). Findings revealed that larger seed had higher potential of producing vigorous plants with eventual high crop yield and higher OC.

Seed and fruit size affect soaking and physiological seed quality in Campomanesia adamantium?

The size of fruits and seeds can affect the seed germination process and aspects related to the vigor of the seedlings formed. Our aim was to characterize fruit and seed biometrics, evaluate the effect of seed size on soaking and the effect of seed size and temperature on the germination and vigor of Campomanesia adamantium . The fruit was evaluated to determine longitudinal diameter, transverse diameter, fresh mass and empty, full and total seed quantities. The seeds were sorted into small, medium and large classes and then measured for length, width, thickness and mass. Seeds from each class were submitted to the germination test at 25 and 30 °C. The germination and vigor (first count, germination speed index, mean germination time and seedling length) data were evaluated by analysis of variance and a means test. Seeds from each size class were weighed repeatedly during soaking. The soaking data were fit to logistic and Peleg models and best fit curves with confidence bands were constructed to compare the effect of seed size. Fruit morphology showed high intraspecific variability. Germination was not affected by seed size or test temperature. Large seeds yielded taller seedlings while the 25 °C germination temperature produced the highest seedling growth rate. The small and medium seeds showed all three phases of the soaking process. Finally, soaking was initially slower for the large seeds than for the small and medium seeds.

Herbicidal bioactivity of natural compounds from Lantana camara on the germination and seedling growth of Bidens pilosa

ABSTRACT Lantana camara (L.) is considered one of the main invasive plants, and the allelochemicals produced by this species can be defined as bioactive secondary metabolites that mediate chemical interactions between the plant and other organisms and, therefore, play an important role in its succession and establishment. The present study aimed to investigate the effect of L. camara aqueous extracts on the germination and growth behavior of Bidens pilosa (L.) by evaluating physiological parameters (germination rate, germination speed index, seedling performance and structure and membrane integrity), as well as the extract metabolic profile. The extract reduced the germination speed index and seedling growth rate and promoted abnormalities in the geotropism and root development in both populations. The third germination phase was highly affected (more than the phases I and II). Lantadene A and B are the possible compounds conferring the herbicidal properties, and the L. camara extract has a potential to be used in the development of a new environmentally-friendly herbicide.

Biochar enriched with organic fertilizer improves the survival and growth rate of Anthocepalus cadamba seedlings planted on degraded spodosols

Syahrinudin, Hartati W, Sudarmadji T, Krisdianto N, Ibrahim. 2019. Biochar enriched with organic fertilizer improves the survival and growth rate of Anthocepalus cadamba seedlings planted on degraded spodosols. Biodiversitas 20: 3741-3750. The application of biochar for the improvement of soil properties and fertility has drawn enormous interest worldwide nowadays and numerous application options are now available. This research was aimed to evaluate the effects of the application of biochar and organic fertilizers on the survival and growth of Anthocepalus cadamba seedlings planted on degraded spodosols soil on bioassay trial in the nursery. Bioassay trial was carried out in the nursery of Faculty of Forestry, Mulawarman University, Samarinda, Indonesia, employing a 2-factors Completely Randomized Design (CRD) with factor 1 was the rate of biochar application (i.e. six levels of treatment: 0 (control), 2, 5, 10, 25 and 100%v of biochar), and factor 2 (enrichment of organic fertilizers, i.e. with enrichment and without enrichment), and each treatment combination had 3 replications. The results showed that biochar application alone improved height and diameter growth rate of A. cadamba seedlings by 253% and 116% of control treatment (without biochar), respectively. Enrichment of organic fertilizers gave further improvement in height and diameter growth rate of A. cadamba seedlings to 386% and 150% of control treatment (without biochar), respectively. Furthermore, biochar application improved survival and biomass growth rate of the seedlings. Enrichment of organic fertilizers into biochar improved not only seedling growth rate but also more interestingly the carrying capacity of spodosols to biochar application rate. We concluded that biochar application complemented with enrichment of organic fertilizers on spodosols is highly promising for the improvement of both soil carbon sequestration and plant growth performance.

Evaluation of Seed Nut Size as Index of Selection for Superior Seed Quality Attributes in Two Biotypes of Cashew (Anacardium occidentale)

Quality seed nuts are germane to propagation of the cashew plant. Seed nut fraction and genotypes have been identified to influence seed quality of crop plant. Unexpectedly, seed size effect has not been well documented in Brazilian and local biotypes of cashew grown in Nigeria. An experiment was initiated to investigate the effect of three nut sizes and two biotypes of cashew on seed quality (physical and physiological) traits. Seed nut were collected from three cashew plants of the same age of each of the biotypes and were allowed to stay for 60 days after collection. The experiment was carried out in a factorial arrangement laid out in a completely randomized design with three replicates using two factors (nut size and biotypes) in 2011 cropping season in both laboratory and screen house tests. Data were collected on physical characters such as seed length, seed width, 100 seed weight and seed imbibition rate while physiological characters were seed germination and early vigour traits. Data obtained were analysed statistically using Tukey HSD test at 5% probability level. The result revealed that some of the characters were significantly different from one another. Seed nut fraction and biotype had considerable effect on seed length, seed width, seed imbibition rate and 100 seed weight. The two factors (nut size and biotype) interaction had profound effect on seed width only. On seed physiological quality, biotype effect was significant on seedling fresh and dry weights and seedling growth rate whereas seed nut size had considerable effect on seed germination, seedling vigour index, seedling fresh weight and seedling growth rate. The interaction effect of nut size and biotype recorded significant effect on the above four characters. Brazilian biotype had superior physical characters (seed length, width and weight) but with low imbibitions rate while medium and large nut sizes gave the highest seed germination and seedling vigour. Also, medium and large nuts had the highest seedling fresh weight whereas the highest seedling growth rate was recorded with small size seed. However, large, medium and small nut sizes of local biotype had the highest imbibition rate, whereas small, medium and large nut size of Brazilian biotype gave the highest 100 seed weight. On seedling emergence, large nuts of local biotype recorded the highest seedling emergence and seedling vigour index. Medium nuts of the two biotypes of cashew are recommended for cashew seed multiplication. Further research on physiology of cashew nut sizes during storage and osmo and hydro priming treatment effect are necessary and therefore advocated.