Judul: Development of Water Stress Treatment System for Long-term High Brix Tomato Production in Hydroponic Culture
Abstrak: Nowadays, the demand of high brix tomato as known as fruit tomato is increased. Many studies found that water stress treatment can be used for the production of high brix tomato, however, these are obtained for short-term experiment in water content around 50%-80% (Nuruddin et al. 2003; Patane and Consentino, 2010). The effect of water stress treatment on plant growth is well known, but how to operate the water stress treatment to increase the quality of tomato fruits is not known very well. It is not easy to grow health plant in water stress condition. This research introduces visual monitoring system to control severe water stress condition. The objectives of the present study are to develop a water stress treatment system for long-term high brix tomato production in hydroponic culture and evaluate the performance of water stress treatment system in long-term severe water condition with seasonal change on the quantity and quality of tomato fruits. Furthermore, the effect of water stress on plants growth was examined. All data that from this research could be used for database of development of water stress treatment system on tomato plants. Tomato (Solanum lycoperscium L., Momotaro Sakura) plants were grown hydroponically on rock wool slabs in a greenhouse in Faculty of Agriculture, Ehime University. Water stress treatment was applied at 14 weeks after transplanting. Leaf area was monitored by digital camera that pictures were captured every 15 minutes. The water content of the slabs was measured by Water Content Meter once a day at noon. There are two treatments in this research, water stress treatment and control. The water content of slab was maintained around 20%-30% for water stress treatment and 60%-70% for control, which was controlled base on the projected leaf area and water content of slabs. When the projected leaf area was decreased fewer or less than 95% of the maximum projected leaf area which was measured after the last irrigation and the water content of the slab was fewer than 20%, the nutrient solution was supplied to the plant until recovering to 20%. For the growth rate measurement, stem diameter and elongation were measured once a week by caliper and measuring tape, respectively. Fruit diameter, sweetness, and sourness were measured by ISEKI grading machine. The calibrations for sweetness were conducted by destructive method with Refractometer, while the sourness was calibrated by KUBOTA Fruits Selector machine. The results indicated that it took 1.5 hours from full unfuried condition to full recover. Some irregular situations were observed when solar radiation was high and relative humidity was low, water content was around 11% that was lower than the expectation. On the other hand, when solar radiation was low and relative humidity was high, water content was around 40% that was not expected. Low solar radiation and high relative humidity can be contributed to maintain the water content at high level. Stem diameter was 4.4 mm-7.78 mm for water stress and 8.45 mm-11.68 mm for control. Stem elongation rate was 0.08 m week-1-0.18 m week-1 for water stress and 0.17 m week-1-0.25 m week-1 for control. Both
Keyword: high technology greenhouse, irrigation control, high brix tomato, water stress

Judul: Morpho-physiological and Anatomical Response of Tomato and Red Guava Plants from Watering using Infusion System
Abstrak: Cekaman kekeringan merupakan tantangan utama produksi tanaman di wilayah tropis. Penyiraman konvensional seringkali tidak efektif dan efisien terutama pada lingkungan dengan tanah yang mudah meresap air dan laju evaporasi yang tinggi. Salah satu upaya untuk mengatasi hal tersebut adalah pengairan dengan sistem infus. Oleh karena itu, penelitian ini bertujuan menganalisis respon morfofisiologi dan anatomi tanaman tomat dan jambu biji merah terhadap pemberian air dengan sistem infus. Penelitian ini menggunakan Rancangan Acak Lengkap 2 faktor yaitu jenis tanaman (tomat dan jambu biji merah) dan pemberian air (kontrol positif, kontrol negatif, jarum infus besar, dan jarum infus kecil). Hasil penelitian menunjukkan bahwa pada tanaman tomat, perlakuan jarum infus 18G dan 21G tidak mencapai jaringan xilem batang yang menyebabkan terhambatnya pertumbuhan (tinggi, jumlah, dan luas daun); penurunan Kadar Air Relatif (KAR) daun, kadar klorofil a, dan diameter pembuluh kayu akar. Penggunaan jarum infus yang lebih kecil pada tanaman tomat lebih baik daripada yang berukuran besar. Pada tanaman jambu biji merah, perlakuan jarum infus 21G dan 25G menyebabkan terhambatnya pertumbuhan (tinggi dan jumlah daun); penurunan KAR daun; peningkatan rasio akar-tajuk, kadar malondialdehid, dan prolin., Drought stress is a major challenge for crop production in the tropics. Conventional watering is often ineffective and inefficient, especially in environments with soils that easily absorb water and high evaporation rates. One effort to overcome this problem is by application watering using an infusion system. Therefore, this study aimed to analyze the morpho-physiological and anatomical response of tomato and red guava plants from watering treatment using infusion system. This study used a completely randomized design with 2 factors, such as the type of plant (tomato and red guava) and watering application (positive control, negative control, large infusion needle, and small infusion needle). The results showed that in tomato plants, the 18G and 21G infusion needles did not reach the xylem tissue of the stem which caused growth inhibition (height, number, and leaf area); the decrease of Relative Water Content (RWC) of leaves, chlorophyll a, and root xylem vessel diameter. Using smaller infusion needles on tomato plants is better than using large ones. In red guava plants, watering treatment with 21G and 25G infusion needles caused growth inhibition (height and number of leaves); the decreased of RWC of leaves; the increase of root-canopy ratio, levels of malondialdehyde, and proline.
Keyword: Cekaman kekeringan, Pengairan sistem infus, Respon fisiologi, Respon anatomi, Drought Stress, Infusion watering, Physiological responses, Anatomical responses

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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