The aim of the study is to determine students’ learning difficulties at all Public Senior High School (SMA) in Medan. This research is descriptive. The population of the study is all students of class XII totaling 7272 in 21 Public Senior High Schools (SMA Negeri) spread over 15 districts. Samples were taken using Purposive Sampling, they are 524 students of class XII in 7 schools. The techniques for data collection use questionnaires of students’ learning difficulties and interviews. The finding of the study concluded that factors caused the biggest students’ learning difficulties derived from external factors (44%), which consist of laboratories factor (49%), books (45%) and the teacher factor (37%). The percentage of internal factors was (43%), which consist of the talent factor (50%), interest (44%) and motivational factors (36%).

This research was conducted to find out the effect of ab mix nutrient on growth and yield of Pak choi (Brassica chinensis L.) plants under hydroponic wick system condition. The research design used was non factorial Complete Randomized Design (CRD) with 5 levels of ab mix nutrient concentrations (0, 650, 1300, 1950, 2600 ppm), with 3 replications in each treatment. Each repetition consists of 6 plants, making a total 90 experimental units. The parameters observed were plant’s height, number of leaves, leaves area, fresh and dry weight, harvest index, leaf chlorophyll content, and root volume. Data was analyzed by using one way ANOVA, and DMRT as follow up. Research result shows that in hydroponic wick system ab mix nutrient gave very significant effect on pak choi (Brassica chinensis L.) parameters, such as: 1) plant’s height, 2) number of leaves, 3) leaves area, 4) dry weight 5) harvest index, and significantly effect on 6) fresh weight. However, it did not gave significant effect on root volume. The best results for each parameters observed were: number of leaves was 18.78, leaves area was 47.32 cm2, fresh weight was 33.57 gr, dry weight was 2.40 gr and harvest index was 99.15%, all were obtained from ab mix 1950 ppm treatment. The best results for plant height parameter was 8.71 cm obtained from ab mix 2600 ppm treatment.

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This research was aimed to develop a Student Activity Sheet (SAS) based on local potency for biology grade XII which is feasible empirically. Eligibility Worksheet was obtained through validation of subject matter experts to assess the feasibility of the content and presentation of the feasibility of worksheets, design expert to assess the feasibility of the design worksheets to SAS developed. Exploiting local potency in accordance with a curriculum that gives freedom to each school consider the potency of the school and the surrounding area. This can be done by incorporating elements of local potency in learning activities through the creation of learning media in the form of worksheets. Examples of local potencies have been integrated into the SAS are distilled palm wine processing (integrated into cell metabolism, fermentation alcohol), the activity of the material have been incorporated in a biotechnology are activities of coconut extraction to produce edible oil. This research and development using 4-D model of development research which comprises the step of define, design, develop and disseminate, however the disseminate stage of this study was not done. The procedure starts from the development stages: (1) problem analyze; (2) design of SAS; (3) validation and field trials SAS. The instruments used were sheets covering the aspects of feasibility validation of content, presentation feasibility, feasibility of the design and questionnaire responses of teachers and students. Data validation and the questionnaire responses of teachers and students were analyzed descriptively qualitative. Feasibility content and feasibility contents presentation SAS based on local potency at biology grade XII has been developed by subject matter experts is very good, in which the feasibility of the content had an average percentage score of 88.10% and feasibility aspects of the presentation of SAS has an average percentage score of 91.35 %. Feasibility design SAS based on local potency at biology grade XII has been developed according to the expert design is very good with a percentage score of 97.00%.

The preservation and development of Sipahutar pineapple is very important to do. One of the most effective ways is with tissue culture techniques. The aim of this research is to know the effect of 2,4-Diclorofenoxyacetic acid (2,4-D), kinetin, and interaction of both Plant Growth Regulator (PGR) to callus induction on pineapple (Ananas comosus L.) from Sipahutar Sumatera Utara Indonesia. The design of this study used a Factorial Completely Randomized Design, namely is 2.4-D with 3 doses of treatment (0, 1, 2 ppm) as the first and the second factor of kinetin with 3 doses (0, 0.5, 1 ppm). The observation process was conducted for 28 days and 35 days after induction. The parameters observed were the formation time of callus, callus color, callus biomass, and the height of callus pile. The results showed that 2,4-D, kinetin and interaction of 2,4-D and kinetin significantly influenced the time of callus formation, callus biomass, and significant effect on the height of callus pile. The time of callus formation is the fastest on day 8 after induction. The best of callus color is whitish green comes from 2,4-D 0 ppm and kinetin 1 ppm treatment. The highest biomass is 1.69 grams. The highest stack height of callus was 2.32 cm. The highest biomass, stack height, surface area of callus derived from the treatment of 2,4-D 0 ppm and kinetin 0 ppm.

The impact of temperature and potassium fertilizers on the growth, yield, and basic biochemical characteristics of sweet potato, <em>Ipomoea batatas </em>var. Antin- 1, was investigated in lowland and highland terrains. In this study we aimed to determine the different traits of the sweet potato, based on its morphology, physiology, and biochemical composition, following treatments with a potassium fertilizer at different temperatures. The study was undertaken using a nested factorial design. The first factor was temperature at each of the two sites: T1 (lowland) and T2 (highland). The second factor was potassium fertilizer (K₂O) nested within the temperature factor and consisting of four levels of K: K0 (0 kg/ha), K1 (50 kg/ha), K2 (100 kg/ha), and K3 (150 kg/ha). Each potassium treatment was replicated three times at each location. Plant vegetative growth in the lowland region, with a daily average temperature of 26.8 °C, tended to be more bushy, with several different morphological properties: The main stem was longer (160.7 cm) and spreading, the stem diameter was greater, and the petioles were significantly longer in the lowland plants compared with the highland plants; however, no differences were observed in the leaf characteristics. The differential temperature (depending on altitude) resulted in significant differences in relative growth rates (RGR) and net assimilation rates (NAR); the values for RGR-1 and NAR-1 in the lowlands were higher than those in the highlands. The tuber weight, yield index, anthocyanin accumulation, and glucose content were significantly higher in the highland crops than in the lowland plants, which grew under relatively higher temperatures. Potassium applications caused significant differences in the anthocyanin content (mg/100 g fresh weight), anthocyanin production (kg/ha), and glucose production (kg/ha) at different locations.

Penelitian ini bertujuan untuk menganalisis bentuk pemberdayaan masyarakat yang dilakukan melalui Koperasi Bangkit Bersama dengan menggunakan pendekatan kualitatif dan metode wawancara secara  mendalam kepada 5 informan yang terlibat langsung,  dianggap  memahami dan dapat memberikan informasi secara benar yang berkaitan dengan fokus penelitian yang dilakukan. Temuan dari penelitian ini menunjukkan bahwa masyarakat merasakan kesejahteraan baik secara ekonomi dan kelestarian lingkungan sekitar dikarenakan volume sampah yang semakin berkurang, dan ekosistem air yang lambat laun akan membaik dikarenakan eceng gondok yang dimanfaatkan oleh masyarakat. Bentuk pemberdayaan yang dilakukan dengan cara menumbuhkan kesadaran dan  memberikan pelatihan agar masyarakat mempunyai  keterampilan untuk mengolah potensi yang mereka miliki dan  bisa mengatasi permasalah yang mereka hadapi. Empowering Garbage-Gathering Community in Citarum River through Bangkit Bersama Cooperation AbstractThis study aims to analyze the form of community empowerment conducted by Cooperative Bangkit Bersama by using the qualitative approach and in-depth interview method to 5 informants directly involved, explained to know and can provide information correctly related to the research focus undertaken. The findings of this study indicate that the people recognize the prosperity both economically and the sustainability of the around environment due to the reduced volume of waste, and water ecosystems that will gradually repair due to water hyacinth that is utilized by the community. The form of empowerment is done by raising awareness and providing training so that people have the abilities to cultivate their potential and can solve the problems they face.

This research was emerged based on the facts about the presence of many conceptual problems that lead misconceptions in biology textbooks while teachers rely too much on textbooks as learning source in class. This study were aimed to analyze the misconceptions in the high school biology textbook for grade 12 which shall be used by high school students, grade 12 in the city of Binjai, especially for the subjects (growth and development, metabolism, heredity, evolution, and biotechnology) as well as to determine the percentage of misconceptions categories (misidentifications, overgeneralizations, oversimplification, obsolete concept and term, under generalizations). The research method used in this research is descriptive. The concepts contained in the textbook were analyzed by using analysis of documents or textbooks based on the criteria of each misconception categories contained in the instrument for misconceptions identification and then comparedto foreign textbooks. The results of this study showed that: (1) the percentage of misconceptions on the subject of (a) the growth and development (26,09%); (b) metabolism (26,09%); (c) heredity (26,09%); (d) evolution (8,69%); and (e) biotechnology (13,04%); (2) the percentage of misconceptions categories: (a) misidentifications (8,69%); (b) overgeneralizations (17,40%); (c) oversimplifications (69,56%); (d) obsolete concept and term (0,00%); (e) under generalizations (4,35%).