The Effect Of Saline-alkilne Stress On Root System Morphological And Yield

It is a method to ameliorate saline-sodic land by planting rice. Thecharacteristics of the soda-sodic land in the west of Jinlin province lead tothe low rice yield and limit the development of rice planting. Root systemas an important organ of plant can absorb the nutrient and water in order tosupply the energy for plants. The morphological index of rice root systemcan reflect the condition of root growth and the root bleeding rate canreflect the activity of roots. So it can show us the activity of rice rootactivity of different growth stage through the studying of the bleeding rate,thus can provide the basis for increase the production of rice. To somedegree, rice production can be raised under conventional cultivationpattern, however, it is a burden for the surroundings of rice paddy throughlong term using the chemical fertilizers. Therefore, the organic cultivationpattern is promoted in saline-sodic land in order to reduce the pressure ofsurroundings. The studies were composed of laboratory experiment andfield experiment. The field experiment was conducted on the Da，an sodicland experimental station (N45°35′58″-45°36′28″,E123°50′27″-123°51′31″) of Jilin province. The field experiment wasdesigned including conventional cultivation pattern and organic cultivation pattern, and used three rice varieties including Dongdao2, Dongdao4andChangbai9. The difference of rice root morphological and yield and yieldcomponents among rice varieties between the two cultivation patterns wasstudied in the field experiment. Neutral salt (NaCl) and basic salt(NaHCO3and Na2CO3) was used to simulate saline-alkaline stress on ricemutant ML04and its wild type G19in the laboratory experiment, and thedifference of root morphological and the K+and Na+contents of theaboveground part were studied in this experiment. The main conclusionsof the paper were as follows:1The laboratory experiment was showed that the habitation of basic salts(NaHCO3and Na2CO3) of rice seedling growth were more serious thanneutral salt (NaCl). The plant height of G19was greater than ML04undersaline-alkaline stress. The fresh weight of ML04of aboveground wasmore than it wild type under NaHCO3stress treatment, and the watercontents of ML04was higher than its wild type of the aboveground andunderground.2The root total length, root numbers and root surface area weredecreasing with the stress concentrations increasing for ML04and its wildtype G19under saline-alkaline stress, however, the root diameter wasincreased with the concentrations increasing. It concluded that the riceseedling root developed to horizontal angle promoted by saline-alkalinestress. 3The root total length, root numbers, root volume and root surface area ofML04were greater than its wild type G19under basic salts stress, thusaccording to this results, it could be inferred that the tolerance of ML04toalkaline was stronger than its wild type.4The K+and Na+contents of rice seedlings under saline-alkaline stressshowed that the Na+content was increasing with the stress concentrationsincreasing, but the K+content had the opposite results. And the K+and Na+contents of ML04were greater than G19under saline-alkaline stress.5The rice growth conditions, root system morphological, yield, yieldcomponents and root activity were studied for Dongdao2, Dongdao4andChangbai9under conventional cultivation pattern and organic cultivationpattern in sodic land. The results showed as follows:(1) The plant height of rice varieties was increasing with the time lapseafter seedlings being transplanted. The plant height of Dongdao4washigher than Dongdao2and Changbai9under two cultivation patterns.The dry weights of aboveground and underground parts of the threerice varieties increased with the time lapse under the two cultivationpatterns, but the aboveground dry weight of Dongdao4was greaterthan Dongdao2and Changbai9under organic cultivation pattern.(2) The study of diurnal change of bleeding sap showed that the bleedingrate of the three rice varieties reached the maximum value at6in themorning. The difference of bleeding rate among rice varieties showed that the bleeding rate of Dongdao4was higher than Dongdao2andChangbai9under conventional and organic cultivation patterns at theheading stage, and there was a significant difference with the other tworice varieties under organic cultivation pattern. However, there was nosignificant difference under conventional cultivation pattern. The ricebleeding rate of Dongdao4was higher than Dongdao2and Changbai9under this two cultivation patterns after three weeks of the headingstage. And there were significant difference among the three ricevarieties under organic cultivation pattern, but there was no differencebetween Dongdao2and changbai9under conventional cultivationpattern.(3) The study of root morphological index of rice varieties showed that theroot total length, root numbers, root surface area and root volume ofChangbai9were more than Dongdao2and Dongdao4in0-5cm,5-10cm,10-15cm and15-20cm soil layers.(4) It was showed that the percent filled spikelet and the1000-grainweight were greater than Changbai9through the study of rice yield andyield components among rice varieties under the two cultivationpatterns in saline-sodic land. And because the1000-grain weight andthe percent filled spikelet were two important index which could reflectthe rice grain yield, theoretically the yield of Dongdao4should higherthan that of Changbai9and the analysis of the date verified this theory. Thus it can be seen that the study of root system is significant. It canprovide guarantee for the growth of rice aboveground through breedingexcellent rice root systems which are appropriate for saline-sodic land.And the rice yield of saline-sodic land can be raised through studyingthe relationship of the rice root morphological index and yield.