KARAKTER MORFOLOGIS DAN PERKEMBANGAN ANATOMIS BIJI MELINJO (Gnetum gnemon L.)

Melinjo seeds (Gnetum gnemon L.) have many benefits, that it is necessary to know its morphological and anatomical characters. This study aimed to determine differences in morphological characters and anatomical development of melinjo seeds at four seed maturity stages. The morphological observation was carried out based on the quantitative and organoleptic characteristics of the melinjo seeds: outer envelope, size, and the color of the middle envelope. Seed development was anatomically observed in slides prepared with a non-embedding method using a sliding microtome then observed through a microscope. The outer seed envelope has a green to blackish-red color in the final stage, while the seed middle envelope has a light-brown to dark-brown in the final stage. The inner seed envelope is thin, non-rigid, and attached on the outside of the endosperm. The seeds' length ranges from ±1,5 cm until ±2,25 cm at the end-stage; seeds width are 1 cm – 1,18 cm; seeds diameter are 1 cm – 1,16 cm. The anatomical development showed tissue thickening and differentiation. The middle envelope is getting thicker: 318,84 μm to 397,29 μm. Endosperm tissue cells undergo cell compaction as the seeds ripen. At the same time, embryonic tissue differentiation forms hypocotyl, epicotyl, and cotyledon.

CHARACTERISATION OF HORDEUM VULGARE CELLULOSE SYNTHASE-LIKE F6 PROMOTER VIA TRANSGENE EXPRESSION IN RICE

Beta-glucan in cereal crops is known as a functional food, which can reduce cardiovascular diseases by lowering blood cholesterol levels. However, beta-glucan content is relatively low in rice grains, despite being relatively abundant in barley and oat grains. Taking advantage of rice as the staple food for Asians, increasing beta-glucan content in rice for their consumption may help to reduce cardiovascular-related diseases among them. Previous attempts in increasing beta-glucan content in rice via transgene expression of beta-glucan synthase genes from barley into rice were unsuccessful due to the use of non-tissue specific as well as constitutively expressing promoter. The current transgenic expression study was performed to characterise the promoter of beta-glucan synthase gene in barley using beta-glucuronidase (GUS) reporter gene. Two fragments of HvCslF6 promoter (2771 bp and 1257 bp) were successfully fused with GUS reporter gene and integrated into rice plants, demonstrated that the promoter was functional in the heterologous plant system. The presence of blue GUS staining was observed on the leaf, root, stem, and grain of the transgenic rice regardless of the promoter length used and stayed functional up to the next generation. GUS qualitative analysis confirmed that the shorter promoter length generated a stronger GUS activity in comparison to the longer one. This indicated that the presence of repressor elements in between the -2771 bp and -1257 bp regions. The preliminary results shed light on the strong promoter activity in the rice endosperm tissue. It can become an alternative to the collection of plant promoters that can be used for grain quality improvement and biofortification.

Endosperm evolution by duplicated and neofunctionalized Type I MADS-box transcription factors

MADS-box transcription factors (TFs) are present in nearly all major eukaryotic groups. They are divided into Type I and Type II that differ in domain structure, functional roles, and rates of evolution. In flowering plants, major evolutionary innovations like flowers, ovules and fruits have been closely connected to Type II MADS-box TFs. The role of Type I MADS-box TFs in angiosperm evolution remains to be identified. Here, we show that the formation of angiosperm-specific Type I MADS-box clades of Mγ and Mγ-interacting Mα genes (Mα*) can be tracked back to the ancestor of all angiosperms. Angiosperm-specific Mγ and Mα* genes were preferentially expressed in the endosperm, consistent with their proposed function as heterodimers in the angiosperm-specific embryo-nourishing endosperm tissue. We propose that duplication and diversification of Type I MADS-genes underpins the evolution of the endosperm, a developmental innovation closely connected to the origin and success of angiosperms.

4-CPA (4-Chlorophenoxyacetic Acid) Induces the Formation and Development of Defective “Fenghou” (Vitis vinifera × V. labrusca) Grape Seeds

For some horticultural plants, auxins can not only induce normal fruit setting but also form fake seeds in the induced fruits. This phenomenon is relatively rare, and, so far, the underlying mechanism remains unclear. In this study, “Fenghou” (Vitis vinifera × V. labrusca) grapes were artificially emasculated before flowering and then sprayed with 4-CPA (4-chlorophenoxyacetic acid) to analyze its effect on seed formation. The results show that 4-CPA can induce normal fruit setting in “Fenghou” grapes. Although more seeds were detected in the fruits of the 4-CPA-treated grapevine, most seeds were immature. There was no significant difference in the seed shape; namely, both fruit seeds of the grapevines with and without 4-CPA treatment contained a hard seed coat. However, the immature seeds lacked embryo and endosperm tissue and could not germinate successfully; these were considered defective seeds. Tissue structure observation of defective seeds revealed that a lot of tissue redifferentiation occurred at the top of the ovule, which increased the number of cell layers of the outer integument; some even differentiated into new ovule primordia. The qRT-PCR results demonstrated that 4-CPA application regulated the expression of the genes VvARF2 and VvAP2, which are associated with integument development in “Fenghou” grape ovules. Together, this study evokes the regulatory role of 4-CPA in the division and continuous redifferentiation of integument cells, which eventually develop into defective seeds with thick seed coats in grapes.

Total lipid and fatty acid profiles of Coffea arabica endosperm and embryo tissues and their relationship to seed desiccation sensitivity

As seed chemical composition may lead to different responses during drying and other post-harvest operations, the objective of this study was to determine the effect of drying rate (slow and rapid) and the concentration and composition of lipids in the embryo and endosperm tissues of Coffea arabica seeds on desiccation tolerance/ sensitivity. The total concentration of lipids and the composition of fatty acids were evaluated in isolated embryos and endosperms, and in whole (intact) seeds. Embryos had a higher total lipid concentration (23%) than endosperm tissue (8%). Linoleic acid was the predominant fatty acid, with concentrations of 48% in the endosperm and 34% in the embryo tissues. Although rapid or slow drying did not change the fatty acid profile in the embryos or endosperms, the palmitic and linoleic acid concentrations varied significantly between the embryo and endosperm. The predominance of linoleic acid in the endosperm supports the hypothesis that the endosperm tissue may be an important source of damage to the seed and may advance seed deterioration. This indicates that unsaturated fatty acids may have a greater effect on sensitivity to desiccation than the percentage of total lipids.

Endosperm variability: from endoreduplication within a seed to higher ploidy across species, and its competence

Endosperm tissue that nourishes the embryo during seed development, upon maturity, nourishes the global population with special reference to cereal crops like maize, wheat and rice. In about 70% of the angiosperms, endosperm genome content is ‘3n’ with 2:1 (maternal:paternal) contribution, as a result of the second fertilization event. However, angiosperms evolution also documents diversity in endosperm genome content from ‘2n’ to ‘15n’, in scale with the corresponding maternal genome dosage variability (‘1n’ to ‘14n’), whereas paternal contribution is invariable. In apomicts, due to lack of fertilization, or pseudogamy (fertilization of the central cell for endosperm formation), endosperm genome dosage (m:p) has been reported to range between 1:1 and 8:3. Exceptionally, the central cell with one unreduced nucleus and fused with a reduced sperm cell, with 2:1 normal genome dosage, has been reported in Panicum. Altered genome dosage levels are reportedly correlative with eccentricities among maternal and paternal contribution to seed resource allocation. Besides endosperm ploidy variability between species of angiosperms, the present review gives an overview of the ploidy variability in endosperm cells within a seed, up to ‘690n’. In addition to genome-scale variability in the endosperm, some taxa of angiosperms exhibit chlorophyllous endosperms and some chlorophyllous embryos. Also, endosperm cell number during seed development is reported to have a strong association with grain weight at maturity. Genes underlying these traits of variability are unknown, and the present review underscores the variability and highlights the potential of the single-cell sequencing techniques towards understanding the genetic mechanisms associated with these variable traits.

Histochemistry of backcross 1 of oil palm seeds at different storage periods

Oil palm backcross 1 is the result of the crossing between E. oleifera and E. guineensis, followed by backcrossing to one of its parents. It has several advantages, including slow height growth and good oil quality, thereby having the potential to be developed. However, it also has a short seed shelf life, which might be inherited from E. oleifera that has relatively quick seed deterioration. This is problem to the breeding program, and there have not been many studies on the seed deterioration process. A histological examination can determine the composition of food reserves in seed endosperm tissue. Therefore, it is necessary to assess the histochemistry of seeds concerning the process of seed deterioration. Histochemical tests with Sudan III, Milon, and IKI reagents were used as histochemical tests of fat, protein and carbohydrate seed content with different seed storage periods, i.e. 4, 3, 2, and less than 1 year. The result showed that the fat content decreased during the storage periods. Based on carbohydrates and proteins staining, there were only very few substances , which were difficult to distinguish among the storage periods, so that this analysis could not be used as the determining indicator of seed deterioration. The fat content was a determining factor of seed deterioration and quality. The oil palm seed storage up to 3-4 years led to the reduction in the fat content in significant quantities compared to the fresh seeds stored less than 1 year as they still contained a lot of fat in the cell.

Cytoembryological aspects of reduced seed setting in Ranunculus ficaria L. subsp. bulbifer (Marsden-Jones) Lawalrée

Highly disturbed micro- and macro-sporogenesis in <em>R. ficaria</em> L. subsp. <em>bulbifer</em> gives rise to cytologically and genetically unbalanced reproductive cells. In plants from different papulatians, pollen degenerates in various percentages. The majority of apparently normal 7-nucleate ES's undergo abortion. Fertilization occurs sporadically only in ca 7% of ovules. Numerous young achenes undergo degeneration resulting from unviable genotypic combinations. Only 1% of seeds contain multicellular embryos, endosperm tissue and are capable of germination.

Further observations on the physico-biochemical and physiolo gical gradients in the ovule during embryogenesis

In the developing ovule (<em>Clivia</em> sp. and <em>Clivia miniata</em>; exponential phase of embryo growth) the following gradients were found: of osmotic value, concentration of free amino acids, respiration rate in the endosperm tissue, and osmotic value and respiration rate gradients in the embryo. Generally these gradients (with the exception of respiration rate in the embryo) were directed from the chalaza to the micropyde i.e. in the opposite direction of the embryo elongation (imicropyle→chalaza). The obtained results suggest of the direction of some gradients can change during the ovule development.