Seed sprout power, abnormal seeds and dead seed
the statistical analysis of test parameters for seed germination and dead seeds at multiple harvest ages produced results that deviated significantly from the norm, but not for seed parameters (Table 1). There is an effect of harvest age on the quality of the seeds produced, with the highest germination percentage (80.50%) occurring at harvest age 98-100 DAA, which meets the ISTA criteria for good seed quality (2018). This indicated the seed has reached physiological maturity. 101-103 DAA, 104-106 DAA, 107-109 DAA and 110-112 DAA did not differ significantly in terms of harvesting age. The typical germination rate falls below 34.17 per cent. This indicated that the quality of the seed diminished as a result of physiological maturation. This setback will have a negative effect on seed viability, vigor, plant development and yield. At this stage, seeds were vulnerable to environmental influences. According to
Marcos (2015), seeds are physiologically mature when they are no longer genetically related to their parents.
Table 1 depicts the effect of harvest age on the percentage of dead seeds, with the lowest percentage occurring between 98 and 100 DAA. This result indicated that in addition to physiological maturity, the seeds obtained at an age of harvest between 98 and 100 DAA were optimal condition. Due to the condition of the young seeds, the proportion of dead seeds is greatest at harvest ages 101-103 DAA. Internal factors, such as a small embryo size, influence the development of abnormal sprouts. According to
Pereira et al., (2014), embryos vary in size at each maturity stage. Even though they were growing in good reservoirs, these abnormal sprouts cannot develop into normal plants (
Fadhilah, 2020). Some seeds may fail to develop into the optimal embryo for germination, whereas seeds harvested at 110-112 DAA were physiologically mature.
Fresh seeds, seed growing potential and soil emergence test
The statistical analysis of fresh seeds, seed growth potential and soil germination tests conducted at various harvest ages yielded significantly distinct results (Table 2). According to ISTA, fresh seeds did not grow and did not change color until the end of the experiment, but they were not classified as hard seeds. Some seeds in the tetrazolium test turned red (red circle) while others did not change color (black circle). Conditions after soaking in 0.5% tetrazolium can be seen in Fig 1.
Tests for tetrazolium should be conducted on seeds that have been cut and soaked in a solution of TZ (Fig 2). However, based on phase I, the absorbed tetrazolium solution does not necessarily indicate that the seed has germinated. Instead, it indicates that the seed is viable and has the potential to germinate. For instance, the tetrazolium test is useful not only for verifying other indicators of seed vigor, but also for evaluating the presence of damage, which may be the cause of low seed vigor (
Franca-Neto and Krzyzanowski, 2019).
The results are presented in Table 2, which shows that the potential of growing seeds at harvest age 98-100 DAA is 81.83 percent, the highest of the entire harvest life, indicating that the seeds have likely reached physiological maturity at this point.
Mello et al., (2010) state that physiologically mature seeds have perfectly formed embryos and sufficient endosperm to support seed metabolic activity and the development of its essential structures, such as roots, hypocotyls, epicotyls and plumules, so that they sprout normally.
Age of harvest between 98 and 100 DAA yields the best results for SET (Table 1). This is due to the physiological maturity of the seeds and subsequent sun-drying after harvest. Consequently, the seeds are vigorous. In accordance with
Fauza’s (2011) research, post-harvest gambir seeds are obtained from fruit picked when it has reached physiological maturity, but is not rotten and then dried in the sun for three to four days, or until the fruit breaks. According to
Prasad et al., (2016), certain seeds can germinate within a few days of fertilization, with maximum germination occurring later in life.
The day it takes for seeds to germinate 50% (T50) first count test and percentage index value test gambir at various harvest ages
One factor affecting the germination rate of seeds is technical handling during seedlings, such as the medium used. The filter produces 50% more germinated seeds than ultisol soil media in paper media (Table 3). However, filter paper media can only be used to see the percentage of germination, then the growth of plants becomes slow because nutrients are not available to be absorbed by the roots and media conditions since the decreasing of water resistance occurs.
The results of the first counting test or germination of the first count on gambir seeds at various harvest ages indicate that there is no significant difference between the marked results. The results of the first count test (FCT) are shown in Table 3. Growing seeds fail because they are still respirating. The slow growth rate indicates weak seed vigor. However, the harvest age between 98 and 100 is the best indicator of the number of seeds that germinate on the first day. The first day of germination, according to FCT bservations in this study, occurs on day 10. Overall, the calculated FCT value is relatively low. The germination potential and vigor of seeds characterize their physiological quality
(Silva et al., 2016). According to
Melia (2019), pre-germination treatment and seed quality influence FCT. Temperature and humidity will also impact germination rate. The condition of ultisol soil media rapidly dries out, disrupting the hydration process and enzymes and other components that promote germination.
The results of observations of index value test (IVT) or the speed of seed growth at various ages of harvesting after analysis show different results in filter paper media and soil ultisol media. The observations of IVT can be seen in Table 3. Seeds at harvest age 98-100 DAA have a better-growing speed than the entire harvest age. The longer the day needed, the lower the index value. The index value obtained at the harvest age >101 DAA in Table 3 is relatively low because the number of days for the seed to germinate is relatively long. The expression of seed vigor can result from pre-harvest treatments such as drying at too high a temperature or a warm environment, the chemical composition of the seeds and hard seeds.
(Elias et al., 1997).
Observation of physical characteristics
Observations of physical characteristics are also made of the size of the fruit and the number of seeds produced. Observational data are presented in Table 4. Gambir flower has a diameter ranging from 3.82-5.64 cm with an average of 4.5 cm. The size of one seed capsule ranges from 2.45 - 3.05 cm with an average of 2.77 cm. This size may vary depending on the type. The number of seeds in each capsule is 7-195 seeds, with an average of 105 seeds. Based on Fauza’s research (2011), the number of each fruit’s capsules ranges from 25 to 113, with an average of 62 capsules. Therefore, in one flower’s cluster has the potential to produce 22,035 seeds. However, it can differ depending on the climate because the fruit is very easy to fall caused by the extreme weather such as heavy rains and strong winds, which can reduce crop yields.
According to
Ningsih (2012), the physiological maturation process of fruits and seeds usually coincides with the maturing time of the seeds. Physiological maturing of the fruit is also an increase in the production of sugar and water so that there is a change in color in the flesh of the fruit; discoloration occurs due to decreasing levels of chlorophyll and increasing levels of carotenoid and anthocyanin. Observations on the physical condition of the fruit are presented in Fig 3, showing the condition of the fruit at the harvest age of 110-112 DAA is brown and blackish-brown with very broken capsules. Therefore, lesser seeds were harvested.
The color of the fruit at the harvest age of 107-109 DAA is brown and partially broken. It is not much different from the harvest age fruit 104-106 DAA with light brown fruit color. The condition of the fruit at the harvest age of 101-103 DAA is light brown, but some capsules are in a very broken condition. The condition of the fruit at the harvest age of 98-100 DAA is yellowish-green to bright brown, with the condition of the capsule intact until partially broken.
Gambir seeds have an epigeal germination type with mount rooting. The phases of germination of gambir can be seen in Fig 3. Gambir seeds size about 1-2 mm. The structure of the gambir seed consists of wings and embryos. The wings only serve as seed protectors and aid to spread. The enlarged part of the seed embryo contains tissues and living cells that will develop into epicotyls,radicle ,plumules in the germination process.
The germination process (Fig 3) begins with the phase of imbibing, which is characterized by the start of swelling of the embryo in the seed coat (6A) to the appearance of radicle (6B), the growth of radicle followed by hypocotyl lengthening (6C), then the cotyledon comes out of the seed coat and lifts upwards followed by epicotyl growth (6D) and produces intact sprouts that have formed roots, hypocotyl, cotyledon, epicotyl (6E), The end of the seed germination process produces one plant that is intact and continues to grow with multiple leaf growths (6F).
Research on the maturity level of color has been conducted by Rohaeni (2019). She studies the maturity level of coffee fruit based on color showing the red color yield has a 100% seed germination rate. This color grouping needs to be further investigated because each type of gambir result may be different.
