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"Lichens, a unique symbiosis between a mycobiont and a photobiont organism, are known to produce metabolites that can be tapped as biopesticides for agriculture. Such property of the fruticose lichen Ramalina collected within Guimaras Island, Philippines was investigated in this study. A total of 195 specimens were collected and characterized using conventional morphological and chemical analyses. These lichens were identified as Ramalina farinacea, R. roesleri, and R. nervulosa. To test their potential application in agriculture, nine lichen specimens were extracted with acetone and assayed for its inhibitory activities against test bacteria, fungi, and weedy plants. All nine lichen extracts inhibited Pseudomonas aeruginosa (>19 mm ZOI) while only seven lichen extracts inhibited Staphylococcus aureus (13–19 mm ZOI). No inhibitory activity was observed among the fungal plant pathogens Fusarium oxysporum, F. solani, F. verticillioides, Colletotrichum capsici, and C. gleosporioides, and on the Gram-negative bacteria Escherichia coli and Pectobacterium carotovorum var. carotovorum. A decrease in the root (up to 27% reduction) and shoot (up to 39% reduction) lengths, and leaf chlorophyll content (up to 44% reduction) of rice weeds Fimbristylis miliacea, Leptochloa chinensis and weedy rice (Oryza sp.) were also observed. These results, therefore, suggested that the lichen crude extract from Ramalina is a potential biological control for weed management."

"ABSTRAKPentingnya penyimpanan biji telah dikenal manusia semenjak manusia mulai mendomestikasi tumbuhan. Telah diketahui bentuk hubungan antara kadar air dan viabilitas pada biji utuh dan potongan biji yang mengandung embrio Artocarpus heterophyllus Lam. Viabilitas diukur dengan nilai daya hantar listrik (DHL atau konduktivitas). Setiap 1,5 jam sekali dilakukan pengamatan terhadap kadar air biji dan nilai DHL yang dilakukan sampai waktu pengeringan 6 jam melalui 3 macam metode pengeringan (silica gel, matahari, dan oven suhu 40°C).Hasil uji statistik menunjukkan terdapat perbedaan nyata antara kadar air awal biji utuh dan kadar air awal dan potongan biji yang mengandung embrio. Dari ketiga metode pengeringan, silica gel mengeringkan material paling cepat, diikuti pengeringan dengan matahari, dan oven. Bentuk potongan biji yang mengandung embrio lebih cepat mengering daripada biji utuh. Kerentanan biji Artocarpus heterophyllus Lam. terhadap pengeringan memperlihatkan bentuk model regresi yang berbeda antara biji utuh dan potongan biji yang mengandung embrio. Kadar air diduga melalui perhitungan berat kering. Diperoleh hasil bahwa bentuk hubungan yang terjadi pads biji utuh adalah sesuai dengan model Y = 1339,544 - 22,1332X dengan koefisien determinasi sebesar 0,978, sedangkan pada potongan biji yang mengandung embrio adalah mengikuti model Y=965,575 - 14,772X dengan koefisien determinasi sebesar 0,948. Ada pun X adalah peubah kadar air (peubah bebas) dengan Y sebagai peubah viabilitas dengan nilai DHL (peubah).Biji nangka mampu bertahan pada suhu 14°C dengan viabilitas 100% dalam kondisi kadar air tanpa pengeringan dan kadar air 50% selama dua bulan atau lebih. Walau pun demikian kadar air kondisi tanpa pengeringan masih tetap mampu bertahan pada suhu 26°C selama dua bulan. Kadar air awal biji berpengaruh nyata dalam menentukan viabilitas biji selama disimpan.

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ABSTRACT

Seed is the most convenient part of the plant to store and have been known to survive for many weeks. The basic principles of a seed bank are to collect, conserve and provide or exchange germplasm. Seed can be deposited for different periods - short, mid, and long term for different purposes. The longevity of seed is considerable.

Seed can be classified into two groups, orthodox and recalcitrant. Many of seed of tropical tree is recalcitrant. Because many tree species in tropic have the economic value, so study of recalcitrant seed is needed. The aim of this study was to find out the relationship between the seed moisture content decreased with the viability decreased. Therefore, the results can be used as a basic information for the further research.

The research was conducted on two kind of material, the excised embryo and whole seed. Each of those materials was desiccated with three kind of desiccation methods - silica gel, sun, and oven_ The viability is known by a conductivity value.

The effect of desiccation on storability of recalcitrant seed of Artocarpus heterophyllus was studied. As the seed moisture of A. heterophyllus decreased, viability decreased while conductivity value increased. The excised embryo could be desiccated more rapidly rather than whole seed. The silica gel seem to be efective method for seed drying than that of the sun and the oven.

Whole seeds were stored in sealed thin plastic container. Seed with seed coat could germinate on 26°C in one month. In sealed container there were no significantly different of moisture content during eight weeks storage or more. Seed without desiccation is best for maintaining their viability especially at 14°C in sealed container."

"Weed scientists are confident of increasing production through agricultural technology, including herbicides, but do not must ask if the moral obligation to feed people is sufficient justification for the benefits and harms achieved. A continuing, rigorous examination of the science?s goals that leads to appropriate change is advocated. Weed scientists have a research consensus, a paradigm, weeds must be controlled. Herbicides are the best control technology. Agriculture's practitoners should discuss the necessity and risks of their technology. Discussion must include scientific evidence and value-laden arguments."

"The experiment aimed to examine the growth and some physiological parameters of five metal-accumulator weed species in response to mercury (Hg) and lead (Pb) treatment. Five weed species (Branchiaria mutica, Cyperus kyllingia, Ipomea aquatica, Mikania micrantha, and Paspalum conjugatum) were grown in water culture using half strength Hoagland’s solution and subjected to Hg(NO3)2 and PB(NO3)2 at 0,  0.25 and 0.5 mM for 3 weeks. The growth, photosynthesis, lipid peroxidation and proline content were observed during the treatments. The result showed that both Hg and Pb decreased growth significantly, but the decrease was far higher in Hg than in Pb treatments. Hg treatment reduced photosynthetic rate dramatically under different photosynthetic photon flux density suggesting that heavy metal Hg until 0.5 mM caused the damage of photosynthetic apparatus almost all species except in I. aquatica. Hg and Pb treatment caused dramatic increase in leaf MDA content, which was associated with the decrease of chlorophyll content significantly. Almost all the species were tolerant to Pb treatment up to 0.5 mM except M. micrantha, while only C. kyllingia and I. aquatica were tolerant to Hg treatment up to 0.5 mM. Only Hg treatment and not Pb that induced higher proline content in the leaves of threated plants without clear pattern of the increment among the species suggesting that proline may have a role as alarm stress rather than tolerant indicator."

"Mulsa plastik telah banyak digunakan oleh petani di Indonesia dalam budidaya tanaman tomat. Penggunaan mulsa plastik dinilai efektif dalam meningkatkan pertumbuhan tanaman dan menghambat gulma. Namun, penggunaan mulsa plastik dalam jangka panjang dapat mencemari lingkungan karena mulsa plastik sulit terurai. Penggunaan mulsa organik dapat menjadi alternatif dalam menghambat gulma, salah satunya mulsa daun bambu. Mulsa daun bambu diketahui dapat menghasilkan senyawa alelokimia untuk menghambat gulma. Tujuan dari penelitian adalah untuk menganalisis efektivitas penggunaan mulsa daun bambu dalam menghambat gulma dan meningkatkan pertumbuhan tanaman tomat. Penelitian ini dilakukan menggunakan 3 perlakuan yaitu tanpa mulsa, mulsa plastik dan mulsa daun bambu. Setiap perlakuan terdiri atas 4 plot penanaman dan masing-masing plot terdiri dari 2 tanaman tomat. Berdasarkan analisis statistik pertumbuhan tanaman tomat menunjukkan bahwa tidak ada perbedaan secara signifikan pada setiap perlakuan. Sebaliknya, berdasarkan rata-rata pertumbuhan tanaman menunjukkan bahwa mulsa plastik memiliki pengaruh yang lebih baik daripada tanpa mulsa dan mulsa daun bambu. Berdasarkan analisis statistik berat basah buah dan diameter buah menunjukkan adanya perbedaan secara signifikan pada setiap perlakuan. Sedangkan, untuk parameter gulma menunjukkan bahwa pemberian mulsa memiliki rata-rata jumlah dan kerapatan gulma yang lebih rendah daripada tanpa mulsa.

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Plastic mulch has been widely used by farmers in Indonesia in cultivating tomato plants. The use of plastic mulch is considered effective in increasing plant growth and inhibiting weeds. However, the long-term use of plastic mulch can pollute the environment because plastic mulch is difficult to decompose. The use of organic mulch can be an alternative in inhibiting weeds, one of which is bamboo leaf mulch. Bamboo leaf mulch is known to produce allelochemical compounds to inhibit weeds. The purpose of this study was to analyze the effectiveness of using bamboo leaf mulch in inhibiting weeds and increasing the growth of tomato plants. This research was conducted using 3 treatments, namely without mulch, plastic mulch and bamboo leaf mulch. Each treatment consisted of 4 planting plots and each plot consisted of 2 tomato plants. Based on the statistical analysis of tomato plant growth, the results showed no significant difference in each treatment. On the other hand, based on the growth rate of plants, it shows that plastic mulch has a better effect than without mulch and bamboo leaf mulch. Based on the statistical analysis of fruit wet weight and fruit diameter, there were significant differences in each treatment. Meanwhile, weed parameters showed that mulching had an average number and density of weeds lower than without mulch."