Negative Effect of  Salinity Stress on Production and Productivity of Lamtoro Crop
                                                          (Leucaena leucochepala)

                                                               Rahmat Budiarto
                                           Agrotechnology Prime Schollarship Programe                                                                                     Agricultural Faculty Universitas of  Jember
                                                                        Essay

1.Preface
          Over the past decade, our soil condition in Indonesia is damage. We find many problem related with our quality and quantity soil.  One of all is “the more building construction, the less  agriculture will be”. As development country, indonesia deserve to build, but one important point is we have to make it harmonize. The best way to handle this problem is optimalization  the other area like along the coastal line.  As maritime country, Indonesia have long coast line. So that it need to optimalize. Some years ago, along the coastal line such as beach area or mangrove area considered unapriopriate to cultivate. The problem is in those area cause salinity stress for crop.
          Salinity stress is one of environment problem we must to accomplish in order to increase our national prodctivity. Salinity stress is complete problem that need seriously handling program. Cause of salinity stress is various kind such as characteristic of main matter that truly  salin or  salt  much  as statement from Buckman and Brady  (1982) in  F. Kusmiyati, E.D. Purbajanti and B.A. Kristanto (2009). Besides that cause of salt accumulation and abnormal irigation (Tan, 1991). The highly evapotranspiration rate with low rain intensity also be cause of salinity stress, so that saltpetre isnot wash perfectly
          Salinity stress can cause 3 kind of stress in internal body of plant. There are low-high Oxygen presure stress, osmotic stress, and toxicity stress. 3 kind of stress that I mentioned before, can bring negative impact especially impede growt factor of crop. Otomatically it can decrease production of yield and productivity of crop. For example  Lamtoro crop or (Leucaena leucochepala) is one of legume plant that the goal is to suply feed need, like cock feed (lifestock).  Production  of Leucaena leucochepala usually in leaves and petioles (Green subtances). And productivity of Leucaena leucochepala means total yield or production in one unit of land such as Ha. Leucaena leucochepala is a crop that really sensitive with abiotic stress like salinity. Therefore, it is important to discuss the impac of salinity stress for  Lamtoro crop Leucaena leucochepala.

2.Discussion
The examples of salinity stress for lamtoro crop or Leucaena leucochepala  is decrease a number of leave, make leave more narrow, and also decrease dry matter of crop.

NaCl                            Width leave (cm2)             A number of                   Dry Matter of
Consentration (mM)                                              total leave (lamina)         crop (Kg/pot)
              0                        10,71                                        49                                 0,26
             50                        3,95                                         24                                 0,15
            100                       2,52                                         16                                 0,09

Source : (F. Kusmiyati, E.D. Purbajanti dan B.A. Kristanto.2009)

          Salinity stress bring negative effect for crop. Some indicator we use to determine in this research are width leave, total leave, and dry matter of crop. Ratna Yuniati (2004) says that salinity is one of some agriculture problem  that cause decrease production and productivity of crops. Salinity stress can cause low-high Oxygen presure stress, osmotic stress, and toxicity stress.
         Salinity stress cause water defisit in internal body plant. Actually we find the same sign in body plant that on stress of salinity and stress of over dry. Salt at higher concentrations in apoplast of cells generates primary and secondary effects that negatively affect survival, growth and development.Primary effects are ionic toxicity and disequilibrium, and hyperosmolality. Both Na+  and Cl- are inhibitory to cytosolic and organellar processes (Niu et al., 1995; Serrano et al., 1999; Zhu et al., 1998 in  Jenks dan Hasegawa,2005 ). Concentrations > 0.4 M inhibit most enzymes because of disturbances to hydrophobic–electrostatic balance that is necessary to maintain the protein structure (Wyn Jones & Pollard, 1983 in Jenks dan Hasegawa,2005). Besides that high consentration of salt   impose hyperosmotic shock by lowering the water potential causing turgor reduction or loss that restricts cell expansion (Munns & Termaat,1986; Hasegawa et al.,2000; Zhu,2002 in Jenks dan Hasegawa,2005).  Putri et al (2009) also says that impact of lowering influence growt aspect such as height growing of stem, width leave, and close-open stomata.
             Second of all impact is low-high O2 preasure stress.  Cause of high O2 preasure stress  is closed stomata. A closing stomata  have aim. It is in order to decrease water loses rate in internal body plant when crop in water defisit situation. The other impact is impede  CO2 difusion and also decrease the number of total leave and width leave. Decrease total and width leave happend because of small amount fotosintat that produce.  It cause transformation metabolic of crop from fotosinteis to fotorespiration. Whereas defisit O2 can impede absorbtion mineral and organic matter. Cause of  minimal number of absorbtion is microorganism in the soil cannot serve mineral and organic matter for crop.
         Besides that, High concentration of salt in body plant can cause toxicity stress. Hetharie (2008) says that Na+ and Cl-  can destroy or damage DNA dan protein.  High consentration (50 nM and 100 mM) cause vacuole of crop sel full with  Na+ dan Cl- , So that activity meatbolic in internal body crop was unsuccesfull. High consentration also influence nitrogen asimilation especially in Legum crop like Lamtoro. The last, high consentration of salt cause Kalium absorb rate  decrease because impede by high consentration of Na+ when plant have salinity stress, as the statement of Nimbalkar and  Joshi in  Mapegeo (2006). The impact is the number of fotosintat that need to translocation decrease dramatically.

4. Conclusion
        High consentration of salt only have negative impact for Lamtoro crop (Leucaena leucochepala)  because lamtoro really sensitive with abiotic stress. The negative impact (low-high Oxygen presure stress, osmotic stress, and toxicity stress) are decrease total leave, width leave and dry matter of crop. Directly it will decrease production and productivity of  Lamtoro crop.

5.Source
F. Kusmiyati, E.D. Purbajanti dan B.A. Kristanto.2009.Karakter Fisiologis, Pertumbuhan dan
           Produksi Legum Pakan Pada Kondisi Salin(Physiology, Growth and Production of
           Leguminoceae for Feed on Saline Condition).Seminar Nasional Kebangkitan Peternakan – Semarang, 20 Mei 2009 hal 302-309.Fakultas Peternakan, Universitas Diponegoro.
Jenks M. A. dan Hasegawa P. M..2005.Plant Abiotic Stress.United kingdom : Blackwell Publishing
           Ltd.
Mapegao. 2006. Pengaruh Salinitas Tanah terhadap Hasil dan Distribusi Bahan Kering pada Tanaman
           Jagung Kultivar Arjuna Selama Fase Pengisian Biji. Jurnal Agrivogor.6 (1): 9-17
Putri, R.S.J., dkk. 2009. Uji Ketahanan Tanaman Tebu Hasil Persilangan (Sacharum spp. Hybrid)
          pada Kondisi Lingkungan Cekaman Garam (NaCl). FMIPA.ITS Surabaya.
Ratna Yuniati.2004.Penapisan Galur Kedelai Glycine max (L.) Merrill Toleran Terhadap NaCl Untuk
         Penanaman Di Lahan Salin.Jurnal Makara Sains Vol 8 (1) hal 21-24.
Hetharie, H. 2008. Pengujian Toleransi Terhadap Cekaman Salinitas Beberapa Genotip Lokal Kacang
         Hijau. Jurnal Budidaya Pertanian. 4: 132-139.