ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Use of Nutrients and Chlorophyll-a for Fish Catch Estimation in Srinakarin Reservoir, Kanchanaburi Province)

ผู้เขียน:ยุพิน เลิศบุรุษ, นายวิทย์ ธารชลานุกิจ, ศาสตราจารย์, ประทักษ์ ตาบทิพย์วรรณ, Ruangvich Yoonphand

สื่อสิ่งพิมพ์:pdf

Abstract

The study aimed to: 1) formulate a fish catch estimation model for Srinakarin Reservoir in Kanchanaburi Province, using nutrients and chlorophyll-a as indicators for fish catch estimation; and 2) develop a sustainable management policy for the reservoir area and its fisheries resources. From April 2008 to March 2009, water samples were collected every two months at 15 selected sampling stations representing upstream, midstream and downstream areas that included point sources and non-point sources, and for the same period, samples of fish species were collected from six private fish landing ports every month. The results showed that the Srinakarin Reservoir was oligotrophic, containing an average of 4.099 mg/m3 of chlorophyll-a and its water quality was appropriate for aquatic animal life. The distribution of nutrients and chlorophyll-a varied, depending on the period and collection area. Nutrient and chlorophyll-a concentrations upstream were higher than those in the middle and downstream sections. The average concentrations of nutrients were highest in the rainy season (June to September), average in summer (February to May) and lowest in winter (October to January), whereas the average chlorophylla concentrations were highest in summer (5.307 mg/m3) and average in the rainy season and winter (4.591 and 2.399 mg/m3, respectively). The ratio of forage to carnivorous fish was estimated as 1.813:1. All parameters used to estimate the fish catch (FC) showed that the catch had a low positive relationship to chlorophyll-a, whereas nutrients could be used to estimate the fish catch, especially, ammonia nitrogen (NH3-N), which was suitable for fish catch estimation throughout the year. A suitable linear regression model was FC = 29,892 - 90,509 (NH3-N); (R2 = 0.44). Ammonia nitrogen had a moderately negative relationship to the fish catch and could explain up to 44% of the fish catch. Based on the equation developed in the study, the results could be used to estimate the fish catch satisfactorily and also the resultant environmental changes in the Srinakarin Reservoir. This model could be applied to predict the fish catch in other reservoirs in Thailand with the same topographical features.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 045, Issue 2, Mar 11 - Apr 11, Page 233 - 244 |  PDF |  Page

ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Growth, Leaf Chlorophyll Concentration, and Morphological Adaptation of Selected Wax Apple Cultivars in Response to Flooding)

ผู้เขียน:ไพศาล ตันไชย, ดร.ลพ ภวภูตานนท์, ผู้ช่วยศาสตราจารย์

สื่อสิ่งพิมพ์:pdf

Abstract

Growth, leaf chlorophyll concentration and morphological adaptation of young wax apple (Syzygium samarangense (Blume) Merrill & Perry) cvs. Plastic (PT), Thunklao (TK), Phetnamphueng (PP) and Thapthimchan (TC) and Malay apple (Syzygium malaccense) (MA) plants under flooding conditions were investigated. Potted wax apple and Malay apple plants were flooded to 5 cm above the soil surface for 70 days continuously. MA, TK, PP and TC plants survived under this flooding duration while PT plants had gradually died after flooding for 30 days. Vertical splitting of the outer bark was observed immediately above and below the flood level in all cultivars after flooding for 12 – 21 days followed by a development of adventitious roots at stem base below the flood level in most cultivars except for MA plants. Flooded PT plants formed adventitious roots faster than other cultivars while flooded TC plants had greatest mass of adventitious roots. Flooding significantly decreased shoot length, leaf number, leaf area, leaf chlorophyll concentration and dry weight of leaves and roots but increased shoot to root ratio. Severe growth restriction was observed in flooded MA and PT plants. Based on the ability to maintain growth under flooding conditions, PP was the most flood tolerance cultivar with profuse adventitious roots followed by TK and TC, respectively, while PT was the least flood tolerance in this study. MA plants restricted their growth and maintained leaf chlorophyll level to survive flooding without adventitious root formation. The results suggested that these selected wax apple cultivars and Malay apple tolerated to flooding differently and flooding tolerance was not generally associated with the ability to form adventitious roots under flooding conditions.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 042, Issue 2, Apr 08 - Jun 08, Page 197 - 206 |  PDF |  Page