Gibberellic acid induced elongation of lettuce hypocotyls and its inhibition by colchicine

1974 ◽  
Vol 52 (1) ◽  
pp. 259-264 ◽  
Author(s):  
V. K. Sawhney ◽  
L. M. Srivastava

Lettuce (Lactuca sativa L.) seedlings treated with gibberellic acid (GA) for 72 h produced hypocotyls 600% longer than the water controls. The process of elongation was accelerated by GA. Also, for maximum elongation, presence of GA was not necessary after 20 h. Short term treatments of seedlings with GA indicated that the seedlings were most 'sensitive' to GA after 8 h of growth in water. Colchicine inhibited the GA-induced elongation. Its effect was maximal if it was applied within the first 2 h after GA treatment irrespective of the stage of hypocotyl development; the inhibition was progressively lessened after 2 h and lost after 36 h. These kinetic data are presented together with measurements of hypocotyl cell lengths and widths and provide a basis for correlated ultrastructural studies.

Author(s):  
Carolina Santos Barreto ◽  
Fortune Homsani ◽  
Nina C Barboza Da Silva ◽  
Carla Holandino

Lettuce seeds bioassays have been used in many different tests such as: alellopathyc models; developing of new drugs; ecotoxicity tests. In most cases, lettuce (Lactuca sativa L., Asteraceae) has been used because of its sensitivity, simultaneous and rapid germination, reliability of germination percentage and homogeneity of seeds. The main goal was to evaluate the effects of ultra-high diluted gibberellic acid (GA3) on lettuce seeds germination and seedling growth. Experiment was performed using Petri dishes containing one disk of Whatman nº01 paper watered with 1ml of water. In each Petri dish 10 lettuce seeds(Lactuca sativa L.) cv Regina 500 were placed and 2ml of the different treatment solutions were add: GA33µmol, GA3 3CH (10-6), GA3 12CH (10-24), water 12CH and water (no dilution and succussion). One milliliter solutions were added every 2 days of experiment. The experiment was repeated twice and each one consisted in 5 Petri dishes per treatment (n=100). All seeds were maintained in germination incubator under controlled temperature (25°C) and photoperiod (16L/8D). The tested substances were prepared according to Brazilian Homeopathic Pharmacopoeia (Brazil, 2011). The experiment was blinded all the time. All seeds germinated at same time (2 days) and after 7 days the germination rate was the same in all treatments. Root was affected just by Water 12 CH, in which shown the longest length (4.59 cm) when compared with others treatments. Shoot length was higher where gibberellin was added in concentration upper then Avogrado’s number.


1975 ◽  
Vol 56 (6) ◽  
pp. 826-829 ◽  
Author(s):  
Robert D. Keys ◽  
Orrin E. Smith ◽  
Junji Kumamoto ◽  
Jessye L. Lyon

2017 ◽  
Vol 2 (01) ◽  
pp. 115-127
Author(s):  
Siti Hilalliyah ◽  
Intan Sari ◽  
Zahlul Ikhsan

Sistem hidroponik memungkinkan sayuran ditanam di daerah yang kurang subur dan daerah sempit yang padat penduduknya. Alasan penerapan teknik hidroponik yang utama adalah karena terbatasnya lahan pertanian yang produktif untuk memenuhi kebutuhan manusia yang semakin banyak tiap tahunnya, sehingga dibutuhkan suatu terobosan baru untuk memecahkan masalah tersebut. Penelitian ini telah dilaksanakan pada bulan November 2015 sampai bulan Januari 2016 yang bertempat di kampus Fakultas Pertanian Jl. Propinsi Kecamatan Tembilahan Hulu Kabupaten Indragiri Hilir Propinsi Riau.Metode penelitian yang digunakan adalah Rancangan Acak Lengkap (RAL) pola faktorial yang terdiri dari 2 faktor. Faktor pertama adalah jenis POC (N) yang terdiri dari 3 taraf perlakuan yaitu POC Jus Bumi, POC Bonggol Pisang danPOC Limbah Sayuran. Faktor kedua adalah konsentrasi larutan (K) yang terdiri dari 3 taraf perlakuan yaitu 150 ppm, 200 ppm dan 250 ppm. Parameter pengamatan adalah Tinggi Tanaman , Jumlah Daun , Luas Daun , Diameter Batang, Panjang akar ,Volume Akar, Kadar Air, dan Bobot Hasil.Hasil pengamatan menunjukkan bahwa perlakuan jenis POC jus bumi dengan konsentrasi larutan 150 ppm memberikan pertumbuhan dan produksi terbaik untuk tanaman selada secara hidroponik sistem wick. Perlakuan jenis POC limbah sayuran dengan konsentrasi 250 ppm memberikan pertumbuhan dan produksi terbaik selain POC jus bumi sehingga dapat dijadikan sumber POC alternatif.


Author(s):  
Nguyễn Minh Trí ◽  
Nguyễn Hạnh Trinh ◽  
Nguyễn Thị Hoàng Phương

Xà lách (Lactuca sativa L.) là một loại rau ăn lá quan trọng có giá trị dinh dưỡng và kinh tế cao. Cây Xà lách có đặc điểm là loại rau ngắn ngày, có thời gian sinh trưởng ngắn khoảng từ 45 - 55 ngày, có thể phát triển tốt trên nhiều loại đất, là loại rau ăn sống được sử dụng rất phổ biến trong bữa ăn hàng ngày của người dân Việt Nam nên nó được trồng quanh năm, do vậy vấn đề về chất lượng lại càng phải được quan tâm nhiều hơn. Bài báo này giới thiệu kết quả phân tích về dư lượng nitrat và các kim loại nặng (Cu, Pb, Zn) trong rau Xà lách vụ Xuân - Hè 2012 - 2013 ở phường Hương Long - thành phố Huế. Kết quả nghiên cứu cho thấy: đất trồng rau Xà lách tại phường Hương Long – thành phố Huế đạt tiêu chuẩn về hàm lượng kim loại nặng (Pb, Zn) theo QCVN 03:2008/BTNMT, nhưng hàm lượng Cu và nitrat là khá cao. Rau Xà lách thành phẩm có dư lượng nitrat cao hơn 1,21% so với quy định và các kim loại nặng (Pb, Zn, Cu) tồn dư trong rau lại ở mức cao và vượt tiêu chuẩn cho phép nhiều lần sẽ ảnh hưởng đến sức khỏe của người sử dụng.


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